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94 Articles

Welcome to HOW IT WORKS BOOK OF Junior Science

We humans have always been fascinated by our world, and over hundreds of thousands of years we’ve built up a body of knowledge about the things around us so we know what they are, how they work, how they interact, and what the processes are underlying everything from the migration patterns of birds and other animals, to the forces that hold us all on the ground. This is science, and it is one of the most inspiring and vast voyages that mankind has ever made. This edition of the How It Works Book of Junior Science has been jam-packed full of the most incredible things about our planet, from our own bodies to the animals we share the world with, and the science that supports it all. It’s been written…

Welcome to HOW IT WORKS BOOK OF Junior Science

20 HOME EXPERIMENTS

If you’ve ever seen a hovercraft and thought it looks amazing but you’d never be able to have one, think again. You can make one in minutes! It’s just one of our 20 experiments you can do at home, no lab coat required. Not only are they fun to do, but they will also explain some of the basic parts of our everyday lives, like how magnets work, the secret to how planes stay airborne and the reason why plants will stop at nothing to reach sunlight. Using everyday items like combs, rubber bands and string, we will demonstrate real science. After all, the Greeks, Romans and Egyptians never had electron microscopes and spotless purposebuilt labs, but they made huge headway with medicine, geology, engineering and maths, to name a few.…

20 HOME EXPERIMENTS

Inside the atom Dissecting what makes up an atom At the centre of every atom is a nucleus containing protons and neutrons. Together, protons and neutrons are known as nucleons. Around this core of the atom, a certain number of electrons orbit in shells. The nucleus and electrons are referred to as subatomic particles. The electrons orbit around the centre of the atom, which is due to the charges present; protons have a positive charge, neutrons are neutral and electrons have a negative charge. It is the electromagnetic force that keeps the electrons in orbit due to these charges, one of the four fundamental forces of nature. It acts between charged objects – such as inside a battery – by the interaction of photons, which are the basic units of light. An atom…

Explore a nuclear reactor’s core

This image shows a nuclear reactor’s core surrounded by Cherenkov radiation, which gives it the characteristic blue glow. Cherenkov radiation is a unique phenomenon where particles that are electromagnetically charged – such as electrons – and emitted from a nuclear reactor’s core travel faster through its coolant (pressurised water) than the phase velocity of light. This process causes the particles to polarise the water molecules, which then proceed to rapidly descend back to their ground state, expelling photons – hence the perceived blue-white illumination – and intensifying observed radiation levels. As such, the intensity of the core’s fission events is directly related to the intensity of its generated Cherenkov radiation. For a closer inspection of a core’s main features and processes, check out the ‘Inside a nuclear reactor’ boxout below. Inside a…

Explore a nuclear reactor’s core

Building demolition

Modern building demolition is an exquisitely choreographed dance of destruction. Dynamite-triggered ‘implosions’ – where a building collapses in on itself just like a crumbling house of cards – are so violently beautiful that they have even become a spectator sport. Demolition junkies are known to camouflage themselves as shrubs just to get a close-up shot of the carnage. Blowing up a building is easy, minimising damage to nearby structures is the tricky part. There are tumbling walls and flying debris to worry about, not to mention the earthquake-like vibrations produced by millions of tons of crashing cement and steel. The explosives alone can produce high-pressure shockwaves that shatter windows for miles. Demolition experts are called blasters (‘explosives engineer’ lacks a certain punch). They know that the most powerful force on a demolition…

Building demolition

How chemicals power batteries

Batteries are everywhere – in your car, your computer and even your cooker. While some are rechargeable and some are disposable, they all work on the same basic principle. A battery has two poles labelled + and –. They provide more than a handy guide as to which way up the battery goes in your TV remote. Electrons are produced inside the battery and when it’s inert they stay on the negative end. Connect the negative and positive ends with the heads inside a battery compartment and the electrons move to the positive end, producing electrical power. But where do those electrons come from? The reaction of substances inside the battery produces them. Common elements used are nickel and cadmium, but zinc is also popular. The battery ‘plates’ are each made up…

How chemicals power batteries

THE SCIENCE OF FIRE

Most of us encounter some form of fire every day, whether we’re basking in the rays of the Sun, lighting a match or cooking food. It’s likely that early man 500,000 years ago didn’t quite have the method of creating fire nailed down, instead relying on natural occurrences such as lightning to start a fire which they would then store underground in hot ashes for later use. Nowadays we use fire on a much more controlled and regular basis, but the complex physics and chemistry behind how it works are the same as they have always been. From heat intensity to combustion, this article will tell you all about the science behind this powerful phenomenon essential to life. We’ll start small – with what’s going on at an atomic level. The process…

THE SCIENCE OF FIRE

How do noble gases work?

“Noble gases were designated ‘noble’ due to their apparent reluctance to undergo a chemical reaction” There are six naturally occurring noble gases found around our world and beyond. These are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). Together they form Group 18 of the periodic table and are characterised by their lack of colour, smell, taste and flammability in their natural state. Despite being historically referred to as rare and inert, noble gases – which were designated ‘noble’ due to their apparent reluctance to undergo a chemical reaction – are nothing of the sort. In fact, all of these gases are found in Earth’s atmosphere and each is fully capable of being chemically active and producing compounds. The majority of the noble gases – ie argon, krypton,…

How do noble gases work?

Acids and bases

It is widely known that lemons taste sour due to their acid content, soil needs the optimum pH level for plants to grow properly and acid rain can wipe out entire ecosystems. But what really makes one thing acidic and the other one basic (alkaline)? Why can they be so corrosive? And why does litmus paper turn different colours when dipped in acid or a base? Acids and bases can be defined in terms of their concentration of hydrogen ions. Normally an atom of hydrogen consists of one proton and one electron giving it a balanced electrical charge – protons being positively charged and electrons being negatively charged. Take away the electron and you are left with an ion of hydrogen, or a single proton, or ‘H+’, as it is often…

Acids and bases

Making antivenom

Whether it’s a deadly cobra, spider or scorpion, antivenoms offer us one final lifeline against otherwise fatal stings and bites. At current estimates, snake bites alone are responsible for up to 100,000 deaths every year, so the production and development of antivenom is vitally important. The process was devised in 1894 by French bacteriologist Albert Calmette, a student of Louis Pasteur. The poisonous animal is ‘milked’ for venom by gently pressing on the venom glands to test on horses, sheep or goats, etc. The chosen animal is injected with a minute amount of the venom (so little they suffer no ill effects) and its body responds by creating antibodies. These antibodies are then collected via a small blood sample taken from the animal and cooled at two to eight degrees Celsius…

Making antivenom

What is condensation?

Air contains water vapour in various quantities depending on where it is in the atmosphere. The amount of water vapour air can hold is dependent on its temperature – with the amount decreasing as the air itself begins to cool. The lower the air temperature, the less water the air is capable of holding. This increases the overall humidity of the air until – if the temperature drops low enough – the air hits what is known as the ‘dew point’. This is the point at which the excess water vapour literally condenses out of the air and forms water. What’s genuinely fascinating is how this process differs depending on the location of the air. Warm air that’s cooled to the dew point due to expanding and rising forms clouds. The…

What is condensation?

Evaporation and steam

The change of state from a solid or a liquid to a vapour is known as ‘evaporation’. This change of state occurs from the amount of energy the molecules have. Apart from at absolute zero (-273.15 °C), when molecules are said to have zero energy, molecules are in constant motion and, as temperature increases, they gain more and more energy. This in turn increases their movement and, the faster they move, the more likely they are to collide with one another. When these collisions occur, a molecule can gain enough energy – and subsequently heat – to rise up into the atmosphere. However, there is a difference between evaporation of vapour and steam. While vapour can be said to be any substance in a gaseous state at the same temperature as its…

Evaporation and steam

How do superconductors work so efficiently?

Top metal superconductors Here are the best metal (Type 1) superconductors with their critical transition temperatures – which is the point at which it is necessary to cool them before they will superconduct Lead 7.196 K Lanthanum 4.88 K Tantalum 4.47 K Mercury 4.15 K Tin 3.72 K Superconductors are metals (such as lead) or oxides which conduct electricity with no resistance. There’s just one catch – to display their superpowers, they need to be kept at a frosty -260 or so degrees Celsius (-436 degrees Fahrenheit). Peer inside a chunk of lead and you’ll see row upon row of neatly packed ions, bathed in a swarm of electrons. These loose electrons are what conduct electricity – set them into motion and you have an electrical current. At room temperature, the lead ions vibrate away frantically. From an…

How do superconductors work so efficiently?

Chocolate fountain physics

Why does the chocolate flow inwards? Learn how surface tension creates the distinctive fountain shape As well as being a tasty treat at parties, chocolate fountains are also useful for understanding the science of how non-Newtonian fluids – fluids whose viscosity varies depending on how much force is applied to them – move. Mathematics students at University College London have even conducted a study on the topic, examining the different ways the delicious molten chocolate flows through the various stages of the machine. First, a pump creates pressure to force the chocolate up the central pipe, then it thins out as it flows out over the domes. However, the most interesting part concerns how the chocolate then cascades down in curtains. Instead of falling straight down into the bowl below, the chocolate pulls…

Chocolate fountain physics

How do space blankets work?

Marathon runners crossing the finishing line will often be handed a shiny blanket to wrap around their shoulders, but what does this thin piece of foil actually do? Space blankets, also known as mylar blankets, were first developed by NASA to regulate the temperature inside the Skylab space station when its heat shield broke in orbit. They are made from a very thin plastic film coated with vaporised aluminium, giving them a highly reflective surface. While NASA used this to reflect heat away from Skylab and keep it cool, runners do the opposite. As heat radiates off the wearer’s body, the blanket’s shiny surface reflects around 80 per cent of it back, helping to keep them warm. It also helps to slow heat loss through evaporation, which occurs when you sweat.…

How do space blankets work?

Whirlpools are formed by the rising and falling of fast-flowing water through ocean channels on the seabed. Due to this, tsunamis – as seen in Japan – are major whirlpool creators, with their massive waves receding quickly away from the shoreline. If this massive quantity of water is funnelled into narrow channels, a whirlpool can form, with a powerful vortex sweeping water towards its centre in a downdraught. While whirlpools can be dangerous, with rare cases of people drowning in them, there have been no reported cases of boats actually being sunk in their vortices.…

Water slides work by exploiting the power of the Earth’s gravity, the lubricating properties of water and the smooth, frictionreducing surface of artificial plastic and fibreglass composites, in order to generate necessary force and momentum to propel riders through their systems. Slide construction tends to be highly eccentric – tuned to maximise g-forces experienced – with riders funnelled down twisting fibreglass tubes or gullies from an elevated position which is typically between 10-40 degrees. There are three main types of water slide: body slides, tube/raft slides and mechanical hydro slides. The former is the simplest design and relies merely on the relationship between the rider’s mass and the effect of gravity to propel them, with their changing position aided by the plastic, and the fluid properties of water, which help to…

Balloon-popping science

Balloons are made of latex, a special type of polymer called an elastomer. If you were to look at latex under a powerful microscope you would see a tangle of long molecules resembling a plate of cooked spaghetti. Each molecule is linked to its neighbours by bonds called cross-links, forming a dense network. When pulled apart, these tangled molecules straighten out, but as soon as the tension is released they snap back to their original shape, lending latex its stretchy quality. Inflate a balloon and the latex molecules stretch out, putting the balloon’s skin under a large amount of tension. If you then jab the balloon with a needle, you create a tiny fault in the latex. The existing tension rapidly transforms this tiny hole into a big tear, ripping the…

Balloon-popping science

How gravity works

Of all Isaac Newton’s revolutionary discoveries, perhaps none was more ambitious than unravelling the enigma of gravity. In the 1660s, Newton saw an apple fall to the ground and dared to ask, “Why?” Why doesn’t the apple drift slowly upward? Why does water always seek the lowest place? Why does the Moon stay in orbit and not catapult into space? In his day, it was a question of near-religious significance. Instead of meditating on divine mysteries, however, Newton drew up formulas. His law of universal gravitation, as presented in his 1687 treatise Principia, states that every particle of matter in the universe attracts every other particle of matter in the universe with a measurable force called gravity (named for the Latin ‘gravitas’, or weight). The strength of the gravitational force increases…

How gravity works

The science of superpowers

Superheroes are special because they are more than human. Their bodies can do things that we could only dream of, and they have access to technology that is years or even centuries ahead of our own. But they were written by people with their feet planted firmly in reality, and if you look hard enough, some of their powers are not as impossible as they first seem. The first DC comic was printed in 1935, and Marvel’s debut offering followed soon after in 1939. At the time, the first programmable computer had only just been invented, we didn’t know the structure of DNA, and the mobile phone was still decades away. Since then, science and technology have started to catch up with the stories, but are all superpowers within our grasp? Join…

The science of superpowers

Could Batman’s tech exist?

“Batman’s suit is made from Kevlar, which is widely used to protect military personnel” Falling forces We can estimate Batman’s landing speed with a simplified model that discounts the effects of air resistance. Earth’s gravity will cause Batman to accelerate towards the ground at 9.8 metres per second, so measuring the distance, you can find out how fast he will be travelling on impact. If his wings are extended, the acceleration will be less than expected because of drag. Most of Batman’s abilities are the result of an arsenal of gadgets, and many are within our grasp. Take his motorcycle, for example; it has a stealth mode that enables it to disappear, and incredibly, there is already technology that can do something similar. BAE Systems is developing a camouflage material known as ADAPTIV. When…

Could Batman’s tech exist?

Understanding gravity Every mass attracts every other mass, and the resulting force is known as gravity. Newton showed that the force increases as the mass of either object increases, and that it decreases as the distance between them gets bigger. According to Einstein, gravity is actually not a force at all. Superman was born on Krypton, a planet more massive and denser than the Earth. As a result, his bones and muscles are genetically adapted to withstand a greater gravitational pull. But could this explain his superpowers? When human astronauts visited the Moon, they found that they could lift heavy objects with little effort and leap several metres in one bound. The idea is that Superman’s experience on Earth – a relatively low-gravity environment for him – should be much the same. However,…

If he were to travel at the speed of light, The Flash could get to the Moon and back in under three seconds, but reaching the 299,792-kilometre-persecond speed limit of the universe would defy physics. Assuming, however, that he is able to come close to this maximum speed, could The Flash really survive such rapid travel? The first challenge is drag; as The Flash moved through the atmosphere, he would collide with gas and dust particles. The faster he went, the more he would disturb the air, and the more drag he would experience. Moving at such high speeds would also compress the air in front of him, because it just wouldn’t have time to get out of his path. Both the friction and air compression would generate heat, even when…

Animal abilities

Spider silk might look fine and delicate, but weight for weight, it is stronger than steel. It can stretch 30 per cent more than its original length, and can withstand the same pulling force of a thread of steel five times its thickness. It is estimated that a spider silk strand the same thickness as a pencil would be able to bring a Boeing 747 jumbo jet to a standstill mid-flight. Real spiders produce several different kinds of silk, each with a different use, including attaching threads that can be secured to other objects, non-sticky ‘dragline’ threads for dangling, and swathing silk for wrapping. Biologists have managed to use genetic engineering to transfer some of the genes for making spider silk into goats so that they produce silk proteins in their milk.…

Animal abilities

The night gwen Stacy died

In a pivotal moment of comic book history, Peter Parker’s love interest, Gwen Stacy, was pushed off a bridge by the Green Goblin (The Amazing Spider-Man, Issue #121-122, Marvel Comics). In an attempt to break her fall, Spider-Man shoots a line of webbing. Caught on the web, he thinks that Gwen is safe, but when he pulls her up he finds her dead. One argument for why she died is that the sudden stop was too much for her neck to handle. The Green Goblin claims that Gwen died during the fall, but it is the stop, not the fall itself, that is dangerous. Why did Gwen die? Impulse = = Average force x Collision time Mass x Change in velocity The impact force of a collision is related to the mass of the…

The night gwen Stacy died

Super small, super strong

Ant-Man physics Real ants have super strength, and physics can explain why The man behind Ant-Man’s amazing abilities is Dr Henry ‘Hank’ Pym, a fictional scientist who discovers subatomic ‘Pym particles’, capable of altering the size and mass of any object. Impossible? Yes, but there are actually some parallels in real-world science. In 2012, scientists at CERN in Switzerland announced that they had discovered the Higgs boson. It is an elementary particle, thought to be evidence of the existence of something known as the Higgs Field. The field is everywhere, and is responsible for giving other particles their mass. We cannot manipulate the Higgs Field to change the mass of subatomic particles, and it does not affect their size, but the fictional Pym particles could work in a similar way. If Pym particles had…

Super small, super strong

Superhuman suits

“The closest thing to the Arc Reactor is an experimental fusion reactor called a tokamak” Modern powered exoskeletons enable superhuman feats of strength, much like Iron Man’s suit. The XOS 2, made by Raytheon, is an experimental military exoskeleton that lets the wearer lift more than their own body weight using hydraulics, joints, sensors and motors that control a steel and aluminium frame. Real exoskeletons are powered by fuel cells or internal combustion engines, but nothing can compare to Iron Man’s miniature Arc Reactor. The closest thing we have are tokamaks; experimental fusion reactors first developed by the Soviet Union during the Cold War. They are doughnut-shaped, anc contain hot plasma held in place by a powerful magnetic field. The idea is that within the reactor, atoms should fuse, releasing energy in…

Superhuman suits

Superhero supermaterials

Uru This metal ore is found only in Asgard, home to the Norse gods. It can withstand extremes of force and temperature, has an unusual affinity for magical enchantments, and was used to create Thor’s hammer, Mjolnir. Although it sounds far-fetched, the story does have some parallels with reality. Inside the nuclear reactor at the centre of a star, atoms smash together with such force that their nuclei fuse, forming heavier elements with different properties. All of the natural metallic elements we know were created inside these stellar forges, or in the dramatic explosions when massive stars die. Kryptonite Kryptonite is the ore of a radioactive element on the planet Krypton. Despite the name, it has no relation to the real element, krypton – a noble gas that glows white when an electrical current…

Superhero supermaterials

Physics and comics collide

How did you get into using superheroes to explain physics? It actually started when I was teaching just a regular introductory physics class, and I was trying to come up with an example that dealt with momentum and forces that hadn’t been done a hundred times before. Being not just a college professor, but also a comic book aficionado – which makes me simultaneously a nerd and a geek, sorry ladies, already married – it occurred to me that the death of Spider-Man’s girlfriend Gwen Stacy, as portrayed in Amazing Spider-Man number 121, would be a perfect illustration. I did a little calculation, I saw that it all worked out, I put it on an exam, and the students responded very positively to applying their physics principles to a situation that was taken…

Physics and comics collide

Making connections The hyoid in the neck is the only bone that isn’t connected to another bone The human body is composed of an estimated 7 octillion (which written out is 7,000,000,000,000 ,000,000,000,000,000) atoms, making up over 75 trillion cells. At the atomic level, the human body comprises about 60 elements, but the function of many of them is unknown. In fact, 99 per cent of the human body is made from just six elements (see chart for specific percentages). Like all other life discovered to date, we are carbon-based; the biomolecules that make up our bodies are constructed using frameworks made up of carbon atoms. Carbon is almost unique among the elements; it is small in size and can make four covalent bonds to other atoms, allowing it to form the backbone of…

How your blood works

Components of blood Blood is a mix of solids and liquids, a blend of highly specialised cells and particles suspended in a protein-rich fluid called plasma. Red blood cells dominate the mix, carrying oxygen to living tissue and returning carbon dioxide to the lungs. For every 600 red blood cells, there is a single white blood cell, of which there are five different kinds. Cell fragments called platelets use their irregular surface to cling to vessel walls and initiate the clotting process. “Red blood cells are so numerous because they perform the most essential function of blood” Blood is the river of life. It feeds oxygen and essential nutrients to living cells in the body and carries away their waste. It transports the foot soldiers of the immune system, white blood cells, which…

How your blood works

Human respiration

Breathing is not something that we have to think about, and indeed is controlled by muscle contractions in our body. Breathing is controlled by the diaphragm, which contracts and expands on a regular, constant basis. When it contracts, the diaphragm pulls air into the lungs by a vacuum-like effect. The lungs expand to fill the enlarged chest cavity and air is pulled right through the maze of tubes that make up the lungs to the alveoli at the ends, which are the final branching. The chest will be seen to rise because of this lung expansion. Alveoli are surrounded by blood vessels, and oxygen and carbon dioxide are then interchanged at this point between the lungs and the blood. Carbon dioxide removed from the blood stream and air that was…

Human respiration

A look inside your heart

Not only does your heart do amazing things, it does so tirelessly, every minute of every day from the moment you’re born (actually, even a bit before then) to the instant that you die. It weighs somewhere between eight and 12 ounces – slightly more if you’re male, less if you’re female. Its sole purpose is to push blood through your circulatory system, providing crucial oxygen and other nutrients to all your organs. The heart is considered a double pump because the right half sends ‘used’ blood to your lungs. There, the blood drops off a load of carbon dioxide and picks up some fresh oxygen, which you have helpfully provided by breathing. Then the oxygenated blood returns to the left half of the heart. This ‘heart-to-lungs-to-heart-again’ trip is known as…

A look inside your heart

When hay fever attacks

We trample on lawns and mow them down, but eventually grass gets revenge. Its pollen causes many of us to suffer from hay fever, and so do trees, weeds and even some fruit and vegetables. Despite being smaller than the tip of a pin, pollen is carried by the wind and lodges in the nasal lining tissues and throat, where it can cause an allergic reaction. This is when the body mistakenly thinks it has been invaded by a threat, such as a virus. To fight back, the body produces a type of antibody known as immunoglobulin E (IgE) in response to the allergen, causing nasal passages to become inflamed, producing more mucus. This is designed to help flush out the allergens but can actually lead to other symptoms like headaches from…

When hay fever attacks

Kidney functions

Kidneys are bean-shaped organs situated halfway down the back just under the ribcage, one on each side of the body, and weigh between 115 and 170 grams each, dependent on the individual’s sex and size. The left kidney is commonly a little larger than the one on the right and, due to the effectiveness of these organs, individuals born with only one kidney can survive with little or no adverse health problems. Indeed, the body can operate normally with a 30-40 per cent decline in kidney function. This decline in function would rarely even be noticeable and shows just how effective the kidneys are at filtering out waste products as well as maintaining mineral levels and blood pressure throughout the body. The kidneys manage to control all of this by…

Kidney functions

How the liver works

The liver is the largest internal organ in the human body and amazingly has over 500 different functions. In fact, it is the second most complex organ after the brain and is intrinsically involved in almost every aspect of the body’s metabolic processes. The liver’s main functions are energy production, removal of harmful substances and the production of crucial proteins. These tasks are carried out within liver cells, called hepatocytes, which sit in complex arrangements in order to maximise their efficiency. The liver is the body’s main powerhouse, producing and storing glucose as a key energy source. It is also responsible for breaking down complex fat molecules and building them up into cholesterol and triglycerides, which the body needs but which are bad in excess. The liver makes many complex proteins,…

How the liver works

The human hand is an important feature of the human body which allows individuals to manipulate their surroundings and also to gather large amounts of data from the environment that the individual is situated within. A hand is generally defined as the terminal aspect of the human arm, which consists of prehensile digits, an opposable thumb, and a wrist and palm. Although many other animals have similar structures, only primates and a limited number of other vertebrates can be said to have a ‘hand’ due to the need for an opposable thumb to be present and the degree of extra articulation that the human hand can achieve. Due to this extra articulation, humans have developed fine motor skills allowing for much increased control in this limb. Consequently we see improved…

How do your feet work?

The human foot and ankle is crucial for locomotion and is one of the most complex structures of the human body. This intricate structure is made up of no less than 26 bones, 20 muscles, 33 joints – although only 20 are articulated – as well as numerous tendons and ligaments. Tendons connect the muscles to the bones and facilitate movement of the foot, while ligaments hold the tendons in place and help the foot move up and down to initiate walking. Arches in the foot are formed by ligaments, muscles and foot bones and help to distribute weight, as well as making it easier for the foot to operate efficiently when walking and running. It is due to the unique structure of the foot and the way it distributes…

How do your feet work?

The human skeleton explained

The human skeleton is crucial for us to live. It keeps our shape and muscle attached to the skeleton allows us the ability to move around, while also protecting crucial organs that we need to survive. Bones also produce blood cells within bone marrow and store minerals we need released on a daily basis. As a fully grown adult you will have around 206 bones, but you are born with over 270, which continue to grow, strengthen and fuse after birth until around 18 in females and 20 in males. Human skeletons actually do vary between sexes in structure also. One of the most obvious areas is the pelvis as a female must be able to give birth, and therefore hips are comparatively shallower and wider. The cranium also becomes more…

The human skeleton explained

Muscles are often taken for granted. Responsible for every move you make, the primary goal of a muscle is to turn the energy stored in your body into motion. Muscles are broken down into three categories. Skeletal are the type that people in the gym train and which individuals are most commonly aware of, as these are the ones which visibly grow at the gym. Smooth are the involuntary muscles such as blood vessels, airways and your bladder. The final category is cardiac, the muscles of the heart. It is skeletal muscle, however, that allows humans to both shape their bodies and increase their strength. Skeletal muscles are complex, designed to contract when asked to perform any action. If you performed a bicep curl, for example, your brain will send a…

What’s inside your head?

From birth, the head of a baby will grow very rapidly. By the age of two the bones will have fused together, although growth continues until the age of seven during which the shape and size of the skull are altered. An adult human head is made from 22 bones. Eight are present in the cranium, and 14 form the face. Together they make up the skull, which provides a framework for all the features of our heads. The primary purpose of the skull is to prevent damage to the brain. Without it, even a small force against the head could cause serious brain damage. Before birth, the skull develops holes in which are found the various features of the head. The skull has three main structural features. Cavities known as orbits…

What’s inside your head?

Dehydration and the body

Just by breathing, sweating and urinating, the average person loses ten cups of water a day. With H2O making up as much as 75 per cent of our body, dehydration is a frequent risk. Water is integral in maintaining our systems and it performs limitless functions. Lubricating the skin, flushing out waste and keeping blood pressure and cholesterol levels stable are just a few of its vital roles. Essentially, dehydration strikes when your body takes in less fluid than it loses. The mineral balance in your body becomes upset with salt and sugar levels going haywire. Enzymatic activity is slowed, toxins accumulate more easily and even breathing can become more difficult as the lungs are having to work harder. Babies and the elderly are most susceptible as their bodies are not as…

Dehydration and the body

Why do we get spots?

Pimples are caused by sensitivity to the testosterone hormone present in both males and females, which can trigger the overproduction of an oily substance called sebum. Sebum, which is produced by sebaceous glands attached to hair follicles in the dermis, helps keep hair and skin waterproof. Your skin is constantly renewing itself, and while new cells are produced in the lower layers of skin, the old dead cells are sloughed away from the surface. This, together with excessive sebum production, can lead to acne and pimples. Sebum normally travels through the hair follicle to the surface of the skin. However, if a pore becomes blocked by a few dead skin cells that haven’t been shed properly, the sebum can begin to build up inside the hair follicle. This oily buildup is the…

Why do we get spots?

How a bruise forms

Bruises are contusions of the skin caused by blood vessels bursting beneath the surface. To minimise bruising after an injury, it is best to put an ice pack on the affected area. The cold will reduce blood flow to that area, limiting the amount that can leak from the blood vessels. As a bruise heals, it puts on a colour-changing display. After two to three weeks of changing from red to blue, then green, yellow and finally brown. However, if a bruise doesn’t fade, your body may have blocked off a pool of blood beneath the skin, forming what is known as a haematoma. The blood then needs to be drained by a doctor. Underneath the surface How a blow to the skin can leave you bruised How a bruise heals The colourful process of repair When…

How a bruise forms

Zika is a ribonucleic acid (RNA) virus, meaning its genetic material is stored in strands of unstable RNA rather than the more stable DNA that most organisms use. Mutations are much more common in RNA, which makes it difficult for other organisms to develop lasting immunity to the virus. It is primarily transmitted via the bite of the Aedes mosquito, which feeds on the blood of infected individuals and deposits the virus into another person’s skin via their saliva. There, it causes the skin cells to digest their own cytoplasm – the fluid that fills the cell. Eventually this causes the cells to break up and die, so the virus can move on to repeat the process in new cells. This leads to the formation of an excess of watery fluid…

The sensory system

The sensory system is what enables us to experience the world. It can also warn us of danger, trigger memories and protect us from damaging stimuli, such as scorching hot surfaces. The human sensory system is highly developed, with its many components detecting both physical and emotional properties of the environment. For example, it can interpret chemical molecules in the air into smells, moving molecules of sound into noises and pressure placed on the skin into touch. Indeed, some of our senses are so finely tuned they allow reactions within milliseconds of detecting a new sensation. The five classic senses are sight, hearing, smell, taste and touch. We need senses not only to interpret the world around us, but also to function within it. Our senses enable us to modify our…

The sensory system

The Earth’s structure

We take the world around us for granted, but the Earth that we walk upon is a complex blend of layers that together create our planet. Thanks to research in the field of seismology, we now know the makeup of the Earth, its distances and measurements and we even know enough about it to be able to compare it to other planets in our solar system. Essentially, the internal structure of the Earth is made up of three core elements: the crust, the mantle and the core. The crust is the hard outer shell that we live on, split into Oceanic and Continental crusts, and it is comparatively thin. The first layer, the Oceanic crust, is around four to seven miles thick, made up of heavy rocks, whereas the lighter Continental…

The Earth’s structure

25 Earthquake facts

The earthquake and tsunami that devastated north-east Japan in March 2011 demonstrate the terrifying power of these natural phenomena. Almost 16,000 people died and more than a million buildings either wholly or partly collapsed. A year after the event, 330,000 people were still living in hotels or in other temporary accommodation, unable to return home. A further 3,000 people were still listed as missing. The gigantic tsunami waves spawned by the earthquake inundated the power supply and cooling of three reactors at the Fukushima Daiichi power station. The subsequent nuclear accident – the worst to occurr since Chernobyl – caused worldwide panic. Earthquakes are unstoppable and strike with little or no warning, but we know a growing amount about how they work. Scientists have developed networks of sensors for monitoring ground movements,…

25 Earthquake facts

White-water rapids

White water occurs in the upper course of the river when the gradient and obstacles disturb the flow of water, causing it to churn and create bubbles. These bubbles reflect back much of the light that hits them, making the water appear white. Whether a river flows smoothly often depends on its speed, and the steeper the riverbed, the faster the water will flow. The combination of fast-flowing water and obstacles like rocks causes the flow to become turbulent, with unpredictable variation in the speed and direction of the water. This creates a variety of features in the river. Where water doubles back on itself, pockets filled with bubbles open up; these provide much less buoyancy and feel like ‘holes’. Objects lodged in the river, like trees, can act as strainers,…

White-water rapids

What causes rogue waves?

Maritime history has long told of infeasibly tall waves that strike suddenly during calm seas and topple boats. And yet to date little is understood about what causes these mystery waves. An ESA project confirmed the existence of these mammoth swells when it recorded ten waves all over 25 metres (80 feet) during a three-week period in 2001. A rogue wave is defined as being around three times the average height of the other waves around it. So they needn’t actually be massive – just surprisingly large compared with the general sea state. Their very nature makes it difficult to predict or pinpoint their cause as factors such as water depth, currents and other variables will affect the propagation and development of a single wave. Energy can be exchanged between multiple waves to…

What causes rogue waves?

How vegetable sheep survive

About 2,000 metres (6,650 feet) up in the mountains of New Zealand’s South Island, grey shapes stand like a flock of unmoving sheep. These rounded, ovine cushions are actually Raoulia plants, covered in woolly leaves; they are more commonly known as vegetable sheep because of their fluffy whitish appearance. Plants of the high mountains (called alpines) have to survive incredibly tough conditions. In winter they are frozen or buried under snow, while in summer, rain drains downhill and many hours of sunlight bake the land. The cushion shape of Raoulia protects it from the weight of snow and it shelters from high winds by hugging the ground. Its woolly leaves form a winter blanket while their grey colour reflects the Sun’s rays.…

How vegetable sheep survive

Explaining rainforests

Rainforests are found mainly in tropical regions near the equator where the climate is consistently hot and wet, allowing the rapid and prolific expansion of all forms of life, be it flora or fauna. From the heartlands of South America, through the jungles of Africa and India, to the north coast of Australia, the rainforests are a phenomenal breeding ground for evolutionary processes and major players in maintaining the world’s natural cycles, responsible for over 28 per cent of its oxygen turnover. However, despite their massive selection of indigenous life forms and overall importance to the Earth’s oxygen production, the rainforests cover less than six per cent of its surface, a number that thanks to perpetual deforestation is reducing daily, causing many species to be driven to extinction and the climate…

Explaining rainforests

The animals of the rainforests

Rainforests are tremendously rich in animal life thanks to their humid, life-abundant climates. A usual population for an area of rainforest can contain insects, reptiles, amphibians, birds, arachnids and mammals, with a diversity across all its layers unmatched anywhere else on the planet. Among the most exotic inhabitants are the toucans, brightly coloured birds characterised by their enormous rainbow bills, ideal for reaching for fruit and other food in hard-to-reach places, as well as to intimidate potential predators. Another species of animal the eastern rainforests boast is the endangered Bengal tiger, of which there are only about 2,000 left in the wild. The second largest tiger on Earth, Bengal tigers can grow up to over three metres and their average weight is 221 kilograms. As obligate carnivores, the amount of meat…

The animals of the rainforests

How plants work

Truly, it’s not easy being green. But plants not only survive, they thrive all over the globe, without the benefit of muscles, brains or personalities. It’s a good thing they do: plants head up nearly all food chains, pump out the oxygen we breathe, hold offerosion and filter pollutants out of the atmosphere. Over the past 3.5 billion years, they’ve diversified into an estimated 320,000-430,000 separate species, with more coming to light every year. All this stems from one neat trick: harnessing the Sun’s energy to power a built-in food factory. Through this process, called photosynthesis, plants combine carbon dioxide with water to create carbohydrates that they use to grow and reproduce. The earliest plants, similar to today’s algae, didn’t do much other than photosynthesise. They floated around in the ocean, soaking…

How plants work

How rivers work

Beginning life in the mountains, rivers form from streams created through precipitation or springs of water that are sourced from groundwater that has percolated the earth. These streams, known as tributaries, then flow rapidly through V-shaped valleys, over rocky terrain and over rock edges, where they’re known as waterfalls. This is the first of three stages any river goes through and is known as the upper course or youth. By the second stage, known as the middle course or maturity, many tributaries will have joined together to form the main body of water that makes up the river. The river meanders at a medium speed across narrow flood plains, which are areas of flat land lying either side of a river. Flood plains are formed when successive flooding causes sediment to…

How rivers work

The water cycle

The water – or hydrological – cycle is the Earth’s water recycling system. Since water rarely escapes the planet or arrives from space, the water cycle keeps rivers relentlessly flowing into the oceans and the atmosphere supplied with clouds and rain. Without it, life simply couldn’t exist. The water cycle circulates water between the oceans and atmosphere, sometimes via the land. When ocean water is heated, it turns into water vapour, which rises into the atmosphere and is carried by winds. The vapour cools at some point and forms clouds. Around 78 per cent of the rain, snow and other forms of precipitation falling from these clouds goes straight back into the ocean. The rest falls over the Earth’s continents and islands. Some of this water runs into rivers and lakes and…

The water cycle

Waterfall wonders

Big waterfalls are among the most spectacular and energetic geological features on Earth. The thundering waters of Niagara Falls can fill an Olympic-sized pool every second. Visitors are drenched with spray and deafened by volumes reaching 100 decibels, equivalent to a rock concert. A waterfall is simply a river or stream flowing down a cliff or rock steps. They commonly form when rivers flow downhill from hard to softer bedrock. The weak rock erodes faster, steepening the slope until a waterfall forms. The Iguazu Falls on the Argentina-Brazil border, for example, tumble over three layers of old resistant lava onto soft sedimentary rocks. Any process that increases the gradient can generate waterfalls. A 1999 earthquake in Taiwan thrust up rock slabs along a fault, creating sharp drops along several rivers. A series…

Waterfall wonders

The Earth’s atmosphere

Atmospheric layers How the atmosphere is broken up in layers Atmospheric water vapour Moisture in the air The gaseous water vapour in our atmosphere is responsible for our rain, snow, hail, fog, and clouds. If the vapour was to fall evenly over the planet as precipitation, each year 25mm of water will have fallen. Our atmosphere (made up of 78 per cent nitrogen and 21 per cent oxygen, with other gases making up the last per cent) is held in place by gravity and consists of a number of different layers that work together to protect us from solar radiation and to keep consistent temperatures. The atmosphere gets thinner with altitude, with 80 per cent of its mass in the first layer closest to the Earth’s surface. There are five main layers that make up…

The Earth’s atmosphere

Predicting the weather

The simple fact of the matter is that weather is unpredictable. So how is it that we can gather information and make predictions about what conditions on Earth will be like? Most weather phenomena occur as a result of the movement of warm and cold air masses. The border between these bodies of air are known as ‘fronts’, and it’s here that the most exciting weather, including precipitation and wind, occurs. As a body of air passes across different types of terrain – such as over the oceans, low-lying areas or even mountainous regions – air temperature and moisture levels can change dramatically. When two air masses at different temperatures meet, the less dense, warmer of the two masses rises up and over the colder. Rising warm air creates an area…

Predicting the weather

50 AMAZING FACTS ABOUT WEATHER

How many lightning strikes are there each second globally? 100 How high is a typical cloud? 2,000m (6,550ft) How many thunderstorms break out worldwide at any given moment? 2,000 How hot is the Sun? The core is around 15,000,000˚C (27,000,000˚F) We like to be able to control everything, but weather – those changes in the Earth’s atmosphere that spell out rain, snow, wind, heat, cold and more – is one of those things that is just beyond our power. Maybe that’s why a cloudless sunny day or a spectacular display of lightning both have the ability to delight us. Meteorologists have come a long way in their capability to predict weather patterns, track changes and forecast what we can expect to see when we leave our homes each day. But they’re not always right. It’s not their fault,…

50 AMAZING FACTS ABOUT WEATHER

Cut off from the Sun, rain and wind that we experience on the surface, you might assume that meteorological conditions in caves never change. However, the reality is that their climates do vary significantly – not only from location to location, but within individual caves over time. In fact, some examples, like the Er Wang Dong cave system in Chongqing Province, China (pictured here), even host their very own weather systems. Very few caves are 100 per cent cut off from their surroundings, but when they are, they can create their own ecosystems. In the case of Er Wang Dong, it all comes down to an imbalance in the local geography. There are several tunnels around the cave system’s perimeter where wind can blow in. Once trapped underground air from outside…

The carbon cycle

“Some carbon also enters the sea as the ocean absorbs it from the atmosphere” Carbon is a greenhouse gas that helps trap heat and keep the Earth warm. Just as water is transferred around the Earth, carbon atoms also follow a cycle and are used again and again in different environmental processes. You might not be able to see carbon but it is a vital part of how our world works and it moves around the Earth in a variety of ways. Carbon moves from the atmosphere into plants. In the atmosphere it is combined with oxygen and found as carbon dioxide. Plant photosynthesis draws the carbon out of the air to make plant food. The carbon then moves from plants into animals as animals eat the plants. The carbon moves up…

The carbon cycle

What are fossils?

Types of fossilisation Dependent on climate and ground conditions, deceased animals can be fossilised in many ways The origin of life on Earth is irrevocably trapped in deep time. The epic, fluid and countless beginnings, evolutions and extinctions are immeasurable to humankind; our chronology is fractured, the picture is incomplete. For while the diversity of life on Earth today is awe-inspiring, with animals living within the most extreme environments imaginable – environments we as humans brave every day in a effort to chart and understand where life begins and ends – it is but only a fraction of the total life Earth has seen inhabit it over geological time. Driven by the harsh realities of an ever-changing environment, Armageddon-level extinction events and the perpetual, ever-present force of natural selection, wondrous creatures with…

What are fossils?

Earth’s minerals

The term ‘crystal’ is used to describe a solid object that has been created by a structured repeating pattern of the same atoms or molecules. Crystals ‘build’ using a process known as nucleation, which involves the attraction of molecules to one place to form a cluster. This can be achieved independently, which is referred to as ‘unassisted nucleation’, where solute (molecules) dissolved in the solvent collect together on their own; gradually attracting and amassing more particles, therefore growing in size and shape. Assisted nucleation sees the molecules collate using some form of solid matter, such as rock, as a type of collection point. If the molecules remain joined, undisturbed and don’t dissolve back into the surrounding solution, a stable nuclei will form, which attracts more of the same atoms. As this continues…

Earth’s minerals

SUPER VOLCANOES

Many people will remember the airport chaos of spring 2010 when Eyjafjallajokull, one of Iceland’s largest volcanoes, erupted after almost two centuries of slumber. But though it might be hard to believe, considering the mammoth amount of disruption that it caused, the Icelandic eruption was tiny compared to a super-eruption’s devastating power. The Eyjafjallajokull event measured a mere 4 on the Volcanic Explosivity Index (VEI), which rates the power of eruptions on an eight-point scale. A massive VEI 8 blast, on the other hand, would threaten human civilisation. Such a supereruption would spew out more than 1,000 cubic kilometres (240 cubic miles) of ejecta – ash, gas and pumice – within days, destroying food crops, and changing the world climate for years. A super-eruption hasn’t happened in recorded history, but they occur…

SUPER VOLCANOES

NATURAL BORN KILLERS

Whether it’s a lion taking down a wildebeest, or a spider devouring a wasp, the predator–prey relationship is a constant carousel of eat or be eaten. It’s survival of the fittest. Unfortunately, it’s very often the little guy that pays the price for the never-ending march of life. That’s because Mother Nature has gifted many of the predators of the animal kingdom with incredible adaptations to lighten the load and simplify their task, no matter how high up they might be in the food chain. There’s no stronger hunting force than that of a pack. It has the benefit of teamwork, the use of varied skills, as well as safety in numbers. The drawback for animals hunting in groups is that there has to be enough food to go around, but…

NATURAL BORN KILLERS

Hunting with the wolf pack

SEARCH 1When the pack is on the prowl, they’re searching for signs of food (e.g. the smell or tracks of a prey) and assessing favourable factors such as the weather and terrain. A PPROACH 2Once the prey is spotted, the pack approaches. They may herd the prey into a more advantageous area, or track them to cause panic and fatigue. ATTACK GROUP 3 When the prey (often a herd of deer, or other hoofed animals) is panicked and running, the wolves will come in from different sides to lunge at the group. ATTACK INDIVIDUAL 4 Smaller and slower individuals of the herd, such as the very young, weak or elderly are the easiest for the individual wolves to pick off. CAPTURE 5 Once a wolf has taken down a victim, the chase will stop. The wolves will bite to…

Hunting with the wolf pack

Deadly dinosaurs

Evolving from archosaurs (large lizards) in the latter part of the middle Triassic period, dinosaurs quickly gained a strong and prolific foothold all over Pangaea, the super continent which all our continents were once part of. Indeed, as the dominant terrestrial vertebrates through the Jurassic and Cretaceous periods, thousands of species of dinosaur have been unearthed as fossils by palaeontologists all over the world, with new discoveries being presented every year. Among them, huge behemoths with skeletons over 16 metres long and six metres tall, with skulls the size of bath tubs have surfaced and delivered a scary and disturbing glimpse into the creatures that once prowled the countries we still live in today. Among the largest of these giants, a group of massive carnivorous theropods (bipedal dinosaurs) emerged throughout the…

Deadly dinosaurs

How do frogs leap?

The secret to why frogs can jump so far is all in their legs. The ideal way for a frog to evade predators is to leap away in a split second. The amphibians have evolved extremely strong hind legs with specially fused leg bones and proportionally big feet, which are perfect for launching into the air over huge distances, because they enable the frog to push off against the ground for longer periods of time. Using high-speed cameras to examine the anatomy of a frog as it jumps, researchers have discovered the mechanics of how a frog can travel so far. Pre-jump, the muscles in a frog’s powerful hind legs are lengthened and stretched as they sit in the typical crouching position. Upon takeoff the muscles connecting the pelvis to the…

How do frogs leap?

Super-snappy tongues

Imagine if your tongue was 80 per cent of the length of your body, and you could poke it out and then reel it back in again within 20 thousandths of a second. Well, if you’re a lungless Hydromantes salamander that’s one ability you already possess. Creatures like frogs, chameleons and salamanders have a staple diet consisting mainly of insects. In order to make a quick getaway, most of these bugs have evolved sensors that detect even the slightest movements made by their would-be assassins, so the hunter must be able to get close without being detected. To help them grab a bite, some amphibians and reptiles have very long and sticky tongues – perfect for catching flighty prey without having to get so close. While most of these animals strike…

Super-snappy tongues

Dogs’ incredible sense of smell

A human nose might be able to detect more than one trillion smells, but it’s no match for a dog’s. Canines can sniff out explosives, drugs and even follow trails more than a week old. They are able to do this due to the unique way their noses are set up. Humans have a single hole that takes in both air and smells, dogs have a flap of tissue that sends smells one way and air the other, allowing them to process the smells much more efficiently. They even have a system for the other direction, so while humans breathe out through their single nose hole and blow out any smells, dogs can exhale through a couple of small slits in their noses, meaning that any smell stays in their noses…

Dogs’ incredible sense of smell

Amphibians can breathe in and out through their skin – on land and under water – and they take in water not through their mouths but instead through absorbent skin on their underside called a seat patch. Most adult amphibians have lungs, but additional oxygen is taken in through the skin. Some species of salamander have no lungs or gills at all, and just breathe exclusively through their skin. The reason amphibians feel slippery is that their skin is full of glands that produce mucus, which spreads across the surface of the skin. This mucus moistens the skin, making it softer and therefore more oxygen absorbent. Although amphibians have few defences against predators, they do have additional poison glands on their skin that secrete irritating toxins for repelling would-be diners. Most…

Low strength High strength: 5,000 lbs inch2 crocodile has the strongest bite of any known creature, producing a force of around 5,000 pounds per square inch. The muscles that control this bite down have evolved and developed to be extraordinarily strong, and alongside relative speed over short distances on land and the immensely sharp teeth that crocodiles prominently display, this forms an immense weapon for the crocodiles to successfully hunt within a competitive environment. However, although the jaw muscles used to snap the jaw shut are well developed, the muscles used to open the jaw are considerably weaker, so much so that if the jaw is taped shut or a large rubber band is put around it, the muscles are not strong enough to push up against the force created by these.…

Commonly misunderstood, the crocodile death roll is a unique method to feed off previously killed prey, not a method to kill them. The most famous user of the death roll is the Nile species of crocodile, common to the Nile River in Egypt. Here, crocodiles use their camouflage and speed to grab large prey and drag them into the water. Once there, the crocodile proceeds to drag the target underwater, holding it there until it drowns. Once the prey is dead, the crocodile then performs the death roll in order to tear large chunks of flesh off its body quickly and efficiently. To do this, it buries its large teeth into the creature’s flesh, before rolling its body 360 degrees. The muscular force of the crocodile’s body in partnership with…

Why do snakes shed their skin?

Snakes shed their skin for two main reasons. The first is to facilitate continued growth. This occurs as snakeskin does not grow in partnership with the snake itself, unlike in humans, where millions of skin cells are shed each year continuously on a microscopic, unseen level. On the contrary, snakes cannot shed skin in this microscopic way, necessitating them to literally outgrow the outer layer of skin whole on a frequent basis. The frequency that snakes shed their skin is largely dependent on the stage of life cycle they are in, with sheddings incredibly frequent during infancy and teenage years (bi-monthly in some species), but slowing to a couple of times per year as adults. The second reason why snakes shed their skin is to preserve their health. Poor living conditions…

Why do snakes shed their skin?

How do snakes bite?

Snakes are highly adapted killers. Non-venomous snakes kill by constriction (suffocation) or swallowing prey alive. Venomous snakes – which make up only ten per cent of the world’s snake species – inject their victims with powerful toxins that either paralyse the respiratory system or attack red blood cells, instantly rotting flesh and bone. Only venomous snakes have fangs, a set of long, hollow teeth in either the front or back of the mouth that act as hypodermic needles. As fangs enter the flesh, the snake flexes its jaw muscle, squeezing toxic saliva out of the venom gland, through the fang’s venom canal and deep into the victim’s tissue. Snakes can control the release of venom, so many defensive strikes against humans are non-lethal ‘dry bites’. If bitten, never try to cut open…

How do snakes bite?

UNDERWATER WONDERS

The open ocean is an extremely dangerous place to live. There are no trees to hide in, no burrows you can dig. Death surrounds you in three dimensions and everything larger than you is a predator. To survive, you have to think big. For some species, this means living as part of a large school of fish. For others, it means actually becoming genuinely, truly enormous. Tiny fish are eaten by small fish. Small fish are eaten by larger fish and so on. In every size bracket, natural selection favours the larger animal over the smaller one. Over millions of years, animal species tend to grow gradually larger and larger until they are too big to fit in anyone’s mouth. Being big is easier in the sea than on land because…

UNDERWATER WONDERS

Life cycle of the emperor penguin

The statistics… Emperor penguin Type: Bird Genus: Aptenodytes Diet: Carnivore, eg fish, squid Average life span in the wild: 15-20 years Height: Up to 130cm (51in) Weight: 25-45kg (55-100lb) While the northern hemisphere experiences winter between December and February, winter in the Antarctic takes place between June and August. One of the only creatures to endure the -30-degree-Celsius (-22-degree-Fahrenheit) temperatures and 160-kilometre (100-mile)-per-hour winds of Antarctica’s harsh winters is the emperor penguin. The stalwart males in particular spend the entire winter in the unforgiving landscape of the frozen continent’s exposed open ice. While pretty much all other Antarctic wildlife heads for milder climes, the emperor penguins stick it out. The reason they do this is so that the new chicks will be fully fledged in midsummer when survival rates are much higher. It’s a treacherous 12 months in the life…

Life cycle of the emperor penguin

Giant pandas explained

There he sits, the giant panda. Solitary, peaceful, resting upright on his furry haunches like a black-and-white Buddha. A born carnivore, this perplexing member of the bear family passes on the meat course almost entirely, choosing to persist on nature’s version of a celery diet: bamboo. A highly endangered animal – less than 2,500 exist in the wild – the panda’s monotonous (nearly monovorous) diet is part of its undoing. The nutritional value of bamboo is negligible, exacerbated by the fact that the panda is genetically incapable of digesting cellulose. The result is that much of the panda’s extremely high-fibre diet passes right through it, providing only minimal calories to an animal that can grow up to 136kg (300lbs) in the wild. So there the giant panda sits, for up to 16…

Giant pandas explained

A hippo may open its mouth wide as a sign of aggression, in a way similar to other animals such as lions and baboons. Opening their jaws shows others their fearsome set of weaponry: their teeth. Although hippos eat vegetation, they do not use their teeth to do so. Their giant canines and incisors are used only for killing. Instead, they use their huge lips to rip grass from the ground for consumption. A hippo is able to spread its lips through a jaw-dropping 150 degrees and up to 1.2m (3.9ft) in width. The strength of a hippo’s jaw muscles – a bite force of 1,800lb – is such that it can use its fearsome teeth to bite a crocodile, human, or even a small boat in half.…

Hibernation explained

While birds and winged creatures can fly to warmer climes to escape cold and fruitless winters, many mammals enter a deep sleep to survive. This state is called hibernation and, depending on the animal, it can last between a few days, weeks, or even months. In preparation for true hibernation, the animal must make a cosy burrow in which to sleep, and eat lots of food to store up as fat. Some animals can survive the whole winter on little or no food as the animal’s heart rate and body temperature decrease, which means they use very little energy during hibernation. Hibernating mammals also have two types of fat: regular white fat, which is used for storing energy and insulating the body, and a special brown fat that isn’t burned for energy.…

Hibernation explained

Ligers and tigons

Ligers and tigons are two resultant species that emanate when lions and tigers cross breed. If a male lion mates with a tigress then a liger is born, if a male tiger mates with a lioness then a tigon is born. Both hybrid species are extinct in the wild as their respective habitats lead to minimal interaction, however many examples of both species can be found in captivity across the world in zoos and wildlife parks. Ligers are now the more prevalent of the two species due to the greater probability of them living past birth, although during the early twentieth century this was not the case. The liger, as with the tigon, shares characteristics from both parent species – ligers enjoy swimming for example, a trait which is associated with…

Ligers and tigons

How flying squirrels glide

Born to fly We break down the squirrel’s flight path from takeoff to landing The statistics… Southern flying squirrel Binomial name: Glaucomys volans Type: Mammal Diet: Omnivore Average life span in the wild: 5 years Weight: 15g-2kg (0.5oz-4lb) Size: 10-90cm (4-35in) Length of glide: 50m (165ft) Many arboreal (tree-dwelling) animals have developed wing-like extensions called patagia, which are elastic membranes stretched between their limbs or toes. These flaps of skin are ideal for helping them to glide through the air either to evade predators or to catch their own prey. The southern flying squirrel is a nocturnal rodent capable of taking to the air and gliding from tree to tree in a single leap. The length of a single flight depends on the height at which the squirrel launches, but some can reach distances of up to 50 metres (165 feet). This…

How flying squirrels glide

Why camels have the hump

Dromedary camel Type: Mammal Diet: Herbivore Average life span in the wild: Up to 50 years Weight: 726kg (1,601lb) Height (ground to hump): 2.1m (6.9ft) Camels are experts at living in places where food and water are relatively scarce. The reason that they can survive in such arid terrain is their amazing ability to conserve the water they do take on so that they can draw upon it later when needed. When a dehydrated camel finds a water source, it can lap up as much as 120 litres (32 gallons) in 15 minutes. To conserve the lifesaving H2O, camels can regulate their body temperature so that they hardly sweat at all. Their kidneys can concentrate the urine to further reduce water loss. Not only this but these creatures also store a lot of water in their blood;…

Why camels have the hump

Why are kangaroos expert jumpers?

Built to bounce Why is this Australian marsupial so good at the long jump? The statistics… Red kangaroo Type: Mammal Diet: Herbivore Average life span in the wild: 20 years Weight: 90kg (200lb) Size: 1-1.6m (3.3-5.3ft) Speed: 56km/h (35mph) In a huge country such as Australia, the ability to cross vast distances in search of food and water is key to survival. And one such animal that can traverse barren lands at high speed for hours is the kangaroo. Capable of an eight-metre (25-foot) single bound across level ground, the red kangaroo is one of the world’s greatest long jumpers. Thanks to large feet and strong legs, it can also travel at over 50 kilometres (30 miles) per hour. While a kangaroo’s hind legs are big and powerful, however, they can’t work independently of each other and so kangaroos have to…

Why are kangaroos expert jumpers?

Why do birds have beaks?

Pelican – fish Pelicans are able to scoop up whole fish in a massive gulp using their elongated bills and store them for later consumption in their elastic throat pouch. Vulture – carrion The vulture’s short, hooked beak is perfect for tearing away strips of flesh from a carcass, so the beak is key to making them such an excellent scavenger. Finch – seeds/insects The finch has a short, stubby beak, but it can vary in length, so different species are suited to a range of environments. Some even use tools like sticks to spear grubs. Kingfisher – fish/insects The lightweight kingfisher’s thin, long beak is perfectly suited for snatching fish and insects out of the water and the air, meaning it can eat on the wing. Toucan – berries This South American bird has the largest beak for…

Why do birds have beaks?

Why leafcutter ants cut leav

Leafcutter ants are a perfect endorsement for teamwork. Living in communities with up to 8 million neighbours, individuals dedicate their lives to a single task, each doing their part for the colony. Workers use their powerful jaws to shear off pieces of leaf all the way from the forest floor to the canopy. They are capable of carrying leaves up to 50 times their own weight – that’s the equivalent of us walking with a family car over our heads – and they’re able to transport even larger fragments by working in groups. But this foliage isn’t their food. It’s used as fertiliser for fungi that they tend in vast subterranean gardens. This fungi nourishes the colony. As well as ensuring the longevity of the nest, the ants’ farming activities – pruning…

Why leafcutter ants cut leav

FISH HEARTS The job of the heart is to pump blood around the body, collecting oxygen and nutrients, dropping them off in the tissues that need it, and transporting waste products away. One of the simplest ways to do this is to have a single pump that moves the blood around in a loop. This is how a fish heart works. Fish hearts have two chambers. The blood comes into the heart through a tube called the sinus venosus, which contains cells that set the rhythm for the muscle. These send waves of contractions into the heart, forcing the blood through it. The first chamber is called the atrium, and it is responsible for collecting blood that has returned from its trip around the body. As it starts to fill up, the…

Similar to but typically much larger than damselflies, dragonflies are large, agile insects that undertake a valuable role in the Earth’s ecosystems, eating mosquitoes and other smaller insects. Their powerful flight abilities stem from their streamlined abdomen and dual sets of intricately veined, membrane wings, which allow them to fly at speeds up to 60mph. Dragonfly wingspans range from one-inch up to six inches. Their agility also stems from large bulging compound eyes, which on some of the larger species grant them almost 360-degree vision. Unfortunately, this high performance comes at a cost – dragonfly muscles need to be warm in order to function properly. Therefore, for dragonfly wings to function optimally, the insect has to engage in a series of stationary wing-whirring exercises and elongated periods of basking in the…

Member of the Lepidoptera family, butterflies are insects that achieve four life stages before turning into all manner of beautiful specimens, including Hesperiidae, Papilionidae and Nymphalidae. This amazing journey sees Lepidoptera begin life as a plain egg that hatches into a larva, or caterpillar, after a period of six days. The caterpillar is an eating machine, consuming constantly for up to four weeks until pupation. Its anatomy makes it adept at consuming all types of plant matter. Using its three pairs of true legs and five pairs of ‘prolegs’ – sucker-like structures with clever little hooks on the end – it grips leaves and plant stems, munching away with powerful mandibles. The caterpillar has an astonishing 4,000 muscles to compliment these feeding habits and a long gut tract to quickly digest…

Ladybirds explained

Coccinellids, more commonly known as ladybirds, or ladybugs in North America, are members of the beetle family. There are more than four and a half thousand different species of ladybirds throughout the world living in warm and temperate regions. Though they vary widely in size and colouration, most of us know them as small red beetles with distinctive black spots, a friend of farmers and gardeners. Like all beetles, ladybirds go through a huge metamorphosis on their way to adulthood. Ladybird eggs hatch into larvae, which oddly look a bit like tiny black-and-yellow alligators. These larvae grow and moult, going through several instars, or developmental phases, over a period of two to three weeks before finally pupating into adults. Ladybirds feature aposematic or ‘warning’ colouration that gives potential predators advanced warning of…

Ladybirds explained

Slugs and snails

Although they look very different, slugs, snails, octopuses, oysters and cuttlefish are all molluscs – Latin for ‘thin shelled’ – and either have a calcium-carbonate external shell, a small shell under the surface, or no shell at all. Slugs are shell-less while adult snails have coiled shells big enough to withdraw into. Slugs and snails belong to the large group of molluscs called gastropods and make their home in a variety of locations from back gardens to oceans and everywhere in-between. They are unique, being the only molluscs that can live on dry land, and breathe using either lungs, gills or both. Gastropods are hermaphroditic, which means they have both male and female reproductive organs, and can mate with themselves if no partner is available. During an elaborate mating ritual slugs entwine…

Slugs and snails

Tardigrades are tiny aquatic invertebrates, known as water bears for their slow gait. The largest species is 1.5 millimetres long, the smallest are under 0.1mm. Despite their squishy and vulnerable appearance, they are virtually indestructible. Lab experiments have shown that they can survive pressures of 6,000 atmospheres, temperatures as low as -272°C or as high as 151°C, and doses of radiation that would kill us a thousand times. They achieve this by dehydrating their bodies with a sugar called trehalose, which acts as scaffolding protecting cell contents. Their water content drops to one per cent of normal in this state and metabolism slows by 99.99 per cent. Ice can’t form in a body this dry and chemical reactions that might harm them occur too slowly to be a danger.…

Termites are cellulose-eating insects that share many similarities with ants and bees, although, perhaps surprisingly, their closest relative is believed to be the cockroach. There are about 2,750 species of termite around the world, living in habitats as varied as tropical forests and the African savannah, through to the Pacific coast. The eating habits of termites make them very important insects in an ecosystem. By consuming wooden structures and plant life they help convert dead trees into organic matter to trigger new life. However, this can cause problems, as they can eat through structural supports in buildings, eventually leading to their collapse. Termites have evolved to eat wood largely because few other animals can; they carry a special bacteria that enables them to digest the tough cellulose fibres. This innate survival mechanism…

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