Science squad Written by Lisa Burke Consultant Professor Robert Winston
Senior editor Sam Priddy Contents Senior art editor Fiona Macdonald Designer and illustrator Bettina Myklebust Stovne 4 Introduction Additional editing Jolyon Goddard, Katy Lennon, 6 Meet the Science Squad 8 The Universe Megan Weal, Amina Youssef 10 The Solar System Managing editor Laura Gilbert 12 Our super Sun Managing art editor Diane Peyton Jones 14 The Earth 16 The Earth’s atmosphere DTP designer Rajesh Singh 18 The Moon Jacket designer Elle Ward 20 The water cycle Producer, Pre-Production Rebecca Fallowfield 22 Solids, liquids, and gases 24 The weather Producer Isabell Schart 26 Dangerous planet Creative director Helen Senior 28 Animals Publishing director Sarah Larter 30 Plants Educational consultants Jacqueline Harris, Trent Kirkpatrick First published in Great Britain in 2018 by Dorling Kindersley Limited 80 Strand, London, WC2R 0RL Copyright © 2018 Dorling Kindersley Limited A Penguin Random House Company 10 9 8 7 6 5 4 3 2 1 001–305910–May/2018 All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form, or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of the copyright owner. A CIP catalogue record for this book is available from the British Library. ISBN: 978-0-2413-0185-2 Printed and bound in China A WORLD OF IDEAS: SEE ALL THERE IS TO KNOW www.dk.com
32 Evolution 60 Materials 34 The Arctic food web 62 Building bridges 36 Ecosystems 64 Take to the skies 38 Inside a rainforest 66 Floating and sinking 40 Climate change 68 Friction 42 Microlife 70 Electricity 44 The human body 72 The Internet 46 Think about it 74 Robots 48 The senses 50 Technology 76 Glossary 52 Simple machines 78 Index 54 Time 80 Acknowledgements 56 Measuring 58 Using numbers
Introduction This book is about science and how it’s used. Science is about trying to understand our surroundings – the world and Universe around us and all the things and creatures in it, from atoms to huge mountains, from tiny bacteria to large whales. As we learn more, we find so much that is puzzling. What lies outside the Universe we can see with a telescope, and how does the brain think and feel love?
It is important to know as much about science as we can so that we use our inventions, our technology, wisely. They can be used for the good of everybody, but science used in the wrong way can be harmful. You are fortunate because we now know so much more than when I was a child, and books like this did not exist. Properly used, the knowledge that science brings helps us to be healthier and to live better lives. Professor Robert Winston
MSeceitethne ce Squad The Science Squad is made up of different subjects that work together to show you how the world works. Science Technology Engineering is all about asking questions uses science to create new is all about finding and designing and discovering the answers machines and more effective solutions to problems – using to explain how things work. ways of doing things. science, technology, and maths. 6
We’ll be here to help you with handy tips! Art Maths is all about using your is about numbers, imagination and style to patterns, and create brilliant new things. problem-solving. 7
TUheniverse The Universe is everything around us. Some of this we can see, but most we cannot. It is a huge expanse of mainly empty space, with billions of galaxies, each containing millions of stars. The Big Bang Light travels really fast, but space is so enormous that it takes time to reach us. This Astronomers believe the Universe means that when we look into the Universe, we exploded out of a tiny point about are only ever viewing the past! Light travels 14 billion years ago. This is known nearly 10 trillion km (6 million miles) a year. as the Big Bang. Before this, the Scientists call this a light year, and use it to Universe did not exist. It is still continuing to expand today. measure the huge distances in space. There are more stars in the Universe than grains of sand on all of the beaches on Earth. 8
The Hubble Telescope travels 600 km (370 miles) above the Earth. It took this photo of the Universe! Astronomers are scientists who study space. It can get really cold in space because the stars and galaxies are so spread out. Our Solar System was formed billions of years after the Big Bang. 9
SThye Ssotlaerm The Solar System is made up of our nearest star, the Sun, and everything that orbits, or travels around, it. This include planets, moons, comets, asteroids, smaller rocks, and dust. Sun People have The Sun is a kind invented ways to study of star that scientists and travel around our call a yellow dwarf. Solar System. Our star Mercury is the smallest planet in The Sun is a medium- the Solar System. Earth is the only sized star. The Sun’s It’s a little bigger planet that we powerful force of than our Moon. know for sure has life on it. gravity pulls on the Earth planets, keeping them teroid belt in orbit around it. Mercury Mars is known as Venus the “Red Planet” as its dusty surface As contains rust. Scientists think the Mars asteroid belt contains the leftover rocks Venus has thousands Many spacecraft have from when the planets of volcanoes on its surface. visited Mars to study were formed. its weather, surface, 10 and rocks.
If it was possible, it would The Kuiper belt is Kuiper belt take a jumbo jet about a very distant part of Pluto 400 years to fly from the Solar System. It is Earth to Neptune. the home of icy dwarf Pluto is the largest planets and comets. dwarf planet in the Satur Kuiper belt. Neptune is theNeptune Saturn has more than 50 moons. It furthest planet from is most famous for the Sun, which makes its rings, which are it freezing cold! made of lumps of ice and rock. Uranus n Unlike the other Launched in 1977, the planets, Uranus spins space probe Voyager 2 on its side. This might reached Neptune in 1989. have been caused by a collision with an Earth-sized object. Jupiter is by far the Milky Way largest planet in our Solar System. It is Our Solar System is part of a galaxy called made mostly of gas the Milky Way. It is spiral in shape and has and has more than more than 100 billion stars. Scientists think there 60 moons orbiting it. is a huge black hole, sucking in dust, gas, and light, at its centre. Jupiter Jupiter is so huge that You are here! all the other planets in the Solar System 11 could fit inside it.
Solar flares Gigantic explosions on the Sun’s surface blast energy outwards. These are called solar flares. Sunspots Dark, cooler patches that develop on the Sun’s surface are known as sunspots. They often appear in pairs and last a few weeks. Our super SunahTmthhyneaedesrcSsnoeiuovgnneretrmniebsoaaooulnflusdoorafunhmrbeeouSaliruournenlmaistntr,ogswSftagyhesraintcseaehemnrsgpd,.yrmI.iottdoissuisttacslyeast The surface of the Sun is a sizzling hot 6,000°C 12 (11,000°F ). That’s 30 times hotter than an oven! At the Sun’s core, temperatures soar to around 15 million °C (27 million °F)!
Total solar eclipse A total solar eclipse occurs when the Moon passes in front of the Sun and covers its face perfectly. This blocks out most of the light, making it appear as if it is night-time. Solar prominences Some sunshine is good Huge eruptions from the for us. We need it to make Sun’s surface are called vitamin D, which helps our solar prominences. They form loops due to the Sun’s bones stay healthy. invisible magnetic field. Lightning 8 minutes It takes eight minutes speed for the Sun’s light to reach Earth. Light travels really fast, but it still takes time to get to us on Earth. A Solar panels light year is the distance a beam of light would travel in one year. 13 Life on Earth Animals and plants depend on energy from the Sun to survive. Technology, such as solar panels, has been developed to absorb the Sun’s energy and turn it into electricity.
he oItnislyejuSpstuoltantsnhufeeortvrive. prlikaEgnnahtotrstwdhainisnttsdoaonacucnorienfthmraaoiolsnmmletifhae.ndThe Earth t Summer happens in the northern half of the world when that part is tilted towards the Sun. Sun rays Countries near the equator have a wet and a dry season, The middle of the planet, rather than spring, summer, the equator, gets a fairly constant amount of autumn, and winter. direct sunshine. Seasons Earth’s axis is tilted at an angle of 23.5˚. We have different seasons on Earth because the planet is slightly tilted. This means that at different times of the year different parts of the planet are closer to the Sun. 14
Land takes up In Crustre about one-third of Upper Mantle the Earth’s surface. Lower Mantle It is colder in the winter because the sunlight Outer Core is weaker. ner Co Inside the Earth The Earth is made many different layers, a bit like an onion. The rocky outer layer is the crust. The upper and lower mantles consist of hot rock, while the outer and inner cores are hot metal. Stardust Everything on Earth is made from materials that were created when dying stars exploded. Even you are made of stardust! Oceans make up most of the Earth’s surface, so our planet looks blue from space. The Earth spins around an imaginary line through its middle, called an axis, once a day. This is why we have day and night. 15
aThtemEaortsh’ps here The atmosphere is a blanket of gases that surrounds and protects the Earth. It keeps us warm, blocks some of the Sun’s harmful rays, and helps stop space rocks from hitting us. Auroras Auroras happen These dazzling coloured lights when tiny particles from dance in the night sky in places the Sun hit particles in close to the North and South Poles. They are also called the our atmosphere. northern and southern lights. Meteorites Weather balloon Space rocks that make it Launched every day, through our atmosphere and weather balloons help hit the ground without burning forecasters predict the up are called meteorites. weather. The balloons carry small tools to measure things, such as air temperature and wind speed. Planes fly high up, where Aeroplanes the air is thinner. This means Planes usually cruise at about 9–12 km (6–8 miles) high. There they can travel easier and are often strong winds at these faster, and burn less fuel. heights, which can make flights turbulent, or bumpy. 16
Exosphere Astronauts have flown out several times to service the Scientists divide our atmosphere into five main layers. The exosphere Hubble Space Telescope. is the outermost layer before outer space begins. Thermosphere Hubble Space Telescope Launched in 1990, this This layer protects us by space telescope travels absorbing a lot of the around the Earth, taking dangerous energy from amazing photographs of the Sun, such as X-rays. distant stars and galaxies. Mesosphere International Space Station This space station has a crew of up Most space rocks that enter to six astronauts. Each stays about the atmosphere burn up in six months, looking after the station the mesosphere. The top of and doing experiments. It orbits the this layer is the coldest part Earth once every 90 minutes. of the Earth’s atmosphere. Venus’s atmosphere Stratosphere Venus’s atmosphere contains thick layers The stratosphere contains the ozone of deadly sulphur-containing clouds. Heat layer. Ozone is a form of oxygen. from the Sun becomes trapped below It stops harmful ultraviolet rays from these clouds. This makes Venus the the Sun reaching the Earth. hottest planet in the Solar System. Troposphere All of our weather happens in the troposphere. It contains most of the air we breathe and a lot of water, including clouds. Venus’s clouds trap heat The gas carbon below them. dioxide makes up 96.5% of Venus’s atmosphere. 17
ThisEeoaMrrbtohit.oinnLegit,s’soatrastkmreaavalel,lclilrnoogscekaryrloowuoonkr.dld, tthheat oon Last manned Moon landing The M Apo15llo 30 July 1971 Apollo 11 December 1972 crater 17 Do you like my space Apollo 20 July 1969 buggy? The proper name 11 for it is a lunar roving First Moon Apo16llo 21 April 1972 vehicle and it runs landing on batteries. Apollo 12 Apollo 14 5 February 1971 19 November 1969 Moon Moon landings Humans first set foot on the Moon in 1969. The flags show where each Moon mission touched down on the surface. 18
There is no air on the Orbiting the Earth Moon, so astronauts have to wear spacesuits so they The Moon travels around the Earth about once every 27 days. The Moon appears can breathe. to change shape in the sky depending on which parts of it are lit by the Sun. The Moon The Earth Apollo spacecraft mosiTstehvtpeehoreSwabelatruurfilugrtnle. srVtocarknoedctket Rockets travel at about 35,400 kph (22,000 mph). That’s pretty fast! Rocket power To get to the Moon, humans had to first develop a rocket powerful enough to launch the Apollo spacecrafts into space. Ladies and gentlemen, The heat produced I present the Saturn V by a rocket could heat 85,000 homes rocket! for a day! 19
wTheater cycle The Sun plays a key part All the water on Earth moves around in a in the water cycle. It heats cycle. It rises into the air as moisture and the Earth, causing liquid clouds. Rain and snow bring it back to the water to become gas. Earth. It then flows along rivers into the oceans, and the cycle goes on. Water droplets Clouds freeze into ice crystals in very As water vapour rises, it cools high clouds. into tiny liquid droplets, which gather to form clouds. This Evaporation process is called condensation. Oceans, rivers, and lakes are Water has been used to warmed by the Sun. As they heat transport people and goods up, liquid water at the surface turns for thousands of years. into water vapour, which is a gas. This process is called evaporation. Seawater contains minerals, which is why it tastes very salty. 20
Rain and snow When a cloud holds enough water droplets or ice crystals, it makes rain or snow. This water falls back to Earth. Winter sports such as skiing rely on a good amount of snowfall! Rainwater is almost pure Back to the sea water, except where it has been polluted by fumes from Rainwater flows over and under the Earth, slowly making its way vehicles and factories. back to the oceans. The water Dams are built to break picks up minerals on its journey. the flow of rivers. We do this to create lakes, Groundwater is water in generate electricity, the soil or rocks in the or prevent floods. ground. It may flow in underground rivers. 21
Saonlidds, lgiqauisdse, s Everything around us is a solid, liquid, or gas. They are all made of something we call “matter”. This, in turn, is made up of tiny particles called atoms and molecules. Liquids The molecules in a liquid are close but If you can pour something, aren’t held together then it’s probably a liquid. as strongly as in a Liquids take on the shape solid. This lets them of the container they’re in. move past each However, they’re hard to other, or flow. squash down. 22
Gases Gas molecules are spread out and move Gases are all around us – the air is about very quickly. made up of gases. A gas will fill any container and can be squashed. Most gases are invisible. Condensation Solids When a gas cools, it turns into a liquid. Solids feel firm and are This is condensation. hard to squash. This book is If you breathe out solid, and so are things that water vapour onto a you can hold, wear, or sit on. cold surface, such as a window, it condenses into water droplets. Evaporation The particles in a solid are Freezing When they are heated, packed together so tightly A liquid freezes to a molecules jump out of that they make a fixed shape. solid at a temperature liquids and become called the freezing point. gas. This is called Melting evaporation. When a solid heats up, its particles vibrate. When it reaches a temperature called the melting point, its particles break free and become liquid. 23
wTheeather The weather affects what people do everyday. One of the reasons it happens Thunder is because the Sun heats up the air, and lightning causing it to move around. This creates lots of different types of weather. Thunderstorms are electrical storms that normally happen in hot, humid Snow Snowploughs clear weather. Lightning is like a giant heavy snowfall to electrical spark. Thunder is the When cloud temperatures are 0°C make travel easier. sound caused by lightning. (32°F) or below, water droplets in the clouds freeze. They form delicate Can you paint all ice crystals and fall as snow! the colours of the rainbow? Rain Clouds are made up of millions of water droplets that fall as rain when they get too heavy. Rainbows form when it is raining and sunny at the same time! Snow chains are put on winter tyres to give vehicles more grip. 24
Large solar panels and batteries power satellites. Sun Weather satellites Some parts of the Earth get more sunshine than others. Weather satellites help That’s why it’s cold at the forecasters to see what North Pole and hot in the the weather is doing. Caribbean. This makes it easier to predict how it might These satellites watch move or change in storms as they move the near future. across the Earth. Special instruments Fog help pilots to land planes safely in fog. Tiny water droplets hanging in the air create cloud at ground level. This is called fog and it is a form of water vapour. Thick fog can make it hard to see into the distance. Wind Wind is caused by warm air rising and cold air rushing in to take its place. 25
Dpalnagenroeuts Tsunamis The top, rocky layer of the Earth Earthquakes happen underwater, is made up of gigantic plates that too. When they occur, it can cause float on a layer of hot rock. Where water levels to rise and create these plates meet, earthquakes and gigantic waves called tsunamis. volcanoes are common. They travel at great speeds and can cause a lot of destruction. Seismographs Earthquake strength is record the measured using the Richter movement of scale. Over eight on the scale the Earth. is a very strong earthquake! The point on the ground In places where earthquakes are directly above the red dot is common, buildings are designed the epicentre. This is where to wobble but not collapse. the most damage occurs. Earthquakes The red dot is called the hypocentre. When plates collide or This is where an scrape against each other, earthquake begins. pressure builds up. After this pressure is released, shock waves travel through the ground. This is known as an earthquake and it can be very dangerous. 26
Volcanoes When magma flows out of a Volcanoes are openings in the volcano it is ground where hot, melted rock, called lava. called magma, escapes from deep underground. It’s best not to be A thermometer measures near a volcano when it’s erupting! lava temperature, which gets as hot as 700-1,300°C Scientists take measurements of changes in the volcano’s (1,300-2,400°F )! shape, vibrations, and gases to Lava can ooze try to predict when the next from cracks in the sides of eruption might be. a volcano. A magma chamber The main vent is a pool of hot, is the biggest melted rock. opening for magma to escape. 27
Fish Reptiles Cold-blooded Fish live in water, breathe Reptiles have scaly skin animals sunbathe in oxygen using gills, and are and are cold-blooded. Most to warm up cold-blooded. They have fins lay eggs. Apart from snakes, their bodies. almost all other types of to help them swim. reptile have four legs. Pandas spend 16 hours each day eating bamboo. Birds Amphibians Birds have feathers, wings, Amphibians, such as frogs and a hollow skeleton. Most can and newts, live in water and fly, but some, such as penguins, on land. They are cold-blooded cannot. Birds lay eggs and and have moist skin. are warm-blooded. Mammals Vertebrates Mammals have hair and are warm-blooded. They give These animals have a birth to live babies, which they backbone and a skull. A strong feed with milk. You are skeleton inside their bodies lets a mammal! them grow larger than invertebrates. Animals There are millions of different types of animal in the world. Scientists divide them into two Less than 5% of all the groups – vertebrates and invertebrates. different types of animal However, all animals have things in common, are vertebrates. There are such as breathing air, moving around to many, many more types find food, and sensing the world. of invertebrate. 28
If a starfish loses one of its arms, it can grow a new one to replace it! Crustaceans Echinoderms Most crustaceans, such as These spiny-skinned animals do crabs, lobsters, and shrimps, not have brains! They include live in or around water. They starfish and sea urchins, and have hard shells. live on the ocean floor. Arachnids Molluscs Spiders, ticks, mites, scorpions, Molluscs have soft bodies. Many, including snails and clams, have and daddy longlegs are all hard shells. Most live in water – types of arachnid. They all for example octopuses – but have eight legs. those living on land must keep damp. Invertebrates Insects Insects have six legs, two These animals don’t have a antennae, or feelers, on their backbone, or spine. Some, such head, an exoskeleton, and many as slugs, are soft and squishy. can fly. There are more than one million known types Others, such as insects, have an exoskeleton, which is a of insect. kind of shell. Small and tall Animals come in all shapes and sizes. Some are so small you need a microscope to see them. Bumblebee bats are the smallest mammals, while giraffes are the tallest animals in the world! Octopuses are the Paper clip Bumblebee bat Adult man Giraffe cleverest invertebrates. 3.2 cm (1.2 in) 4 cm (1.57 in) 1.7 m (5.8 ft) 6 m (20 ft) It’s been found that they can solve problems to get food. 29
Plants Plants get their energy from sunlight. From daisies to palm trees, there are thousands of different types of plant Farming in the world. They provide us with oxygen to breathe, many kinds of food, Farmers grow crops, such as corn, and wood to make homes and furniture. wheat, fruit, vegetables, and cotton. They give their crops fertilizers, which are extra nutrients, to make them grow bigger and faster. Leaves Engineers and scientists A plant’s leaves absorb sunlight, change crops to improve which is used to make food for them – for example, so the plant. The leaves also they don’t get diseases. release oxygen into the air. Stamens Plant parts These parts of the flower make a fine Many plants are made powder called pollen. up of similar parts. They have roots in the soil, Stigma Some plants have strong stems, leaves This part of the flowers, some lose their growing from the stems, flower has a skicky leaves in the winter, and and sometimes flowers. end. It collects pollen some even eat insects! to make seeds. Roots The roots anchor Stem the plant and absorb The stem supports the water and nutrients plant, and both water and from the soil. food travel along it. We get wood from tree stems. 30
Machinery lets farmers Apples, nuts, tomatoes, plough, sow, or harvest huge grapes, cucumbers, and pumpkins are all fields of crops quickly. types of fruit. Butterflies can Fruit carry pollen long distances. Fruit have seeds inside them. When animals eat fruit, the seeds come out in their poo. This way, the seeds are carried to new areas, where they grow into new plants. Insects Fungi Insects spread pollen between flowers Mushrooms and toadstools are not so that they can make seeds. Many plants. They belong to a kingdom of flowers attract insects with a sweet living things called fungi. They feed liquid called nectar. When they come on living or dead plants and animals to drink it, the pollen sticks to them. and soak up their nutrients. Bees are the most important pollen carriers. Mushroom 31
Evolution Over time, animals and plants change, or adapt, so they can survive in their environment for longer and have more babies. This is called evolution. Evolution isn’t a quick process – it takes millions of years! 55 million Whale evolution years ago Pakicetus Incredibly, the ancestors of whales Pakicetus lived on land, possibly lived on land! Over time, they grew near water. It had four hoofed bigger and bigger and moved to feet and sharp teeth for chewing different places, including the ocean. flesh or plants. Natural selection means The powerful that some living things long tail helped are better at surviving to steer in water. than others. 50 million 32 years ago Ambulocetus Short legs and Ambulocetus evolved from padded feet were pakicetus. It lived in water perfect for paddling and hunted like a crocodile. in water. Darwin Wide tail Charles Darwin was a scientist who studied how animals and plants changed over time. He came up with the theory of evolution to explain what he saw.
Bowhead whale By the time the bowhead whale evolved, it had grown enormously in size, with an appetite to match. They feed on a massive 100,000 kg (220,000 lb) of plankton a year! Today Bowhead whales can survive for more Giant flippers than 100 years! Palaeontologists are scientists Breeding who study fossils – the remains of ancient animals and plants. It’s hard to imagine that a chihuahua evolved from a Long, pointed wolf, but it did! Humans breed snout dogs for herding, security, Much smaller legs companionship, and even for than ambulocetus their appearance. 38 million Wolf Chihuahua years ago Dorudon Twelve million years later, the front feet had evolved into flippers and had become webbed. 33
TfoheoAdrctwic eb Arctic tern Animals need food to give them the These seabirds catch fish by energy they need to move and think. A diving into the water at great food web shows what different animals speeds. Adults are safe from in a particular place, or habitat, eat – predators, but their eggs and and how they all link together. chicks are not. Polar bears have white fur so that they blend into their surroundings. Polar bear Polar bears are apex predators, which means they eat other animals, such as ringed seals, but no animals eat them. The killer whale is also known as an orca. Killer whale Killer whales hunt in the ocean and also grab unsuspecting seals near the water’s edge. They are apex predators, too. 34
Plant plankton Some plankton are so rely on the Sun small they can’t be seen for energy. with the naked eye. Arctic cod These fish are a food source for many marine animals. Arctic cod eat plankton, shrimp, marine worms, and sometimes even each other! Ringed seal Plankton This meat-eating animal Tiny drifting animals and eats fish, shrimp, and plants called plankton are plankton, but is hunted eaten by Arctic cod and and eaten by polar coldwater shrimp. bears and killer whales. Draw your own To draw your own food web, start by choosing a habitat, such as a forest or a desert. Now think about what the animals in that habitat eat and show how they link together. Coldwater shrimp Coldwater shrimp live near the ocean floor and mostly eat plankton. They make a tasty snack for seals. 35
Ecosystems Plants and animals live and interact with each other and their surroundings The biggest coral reef in communities called ecosystems. is the Great Barrier Ecosystems can be as small as a tree Reef off the coast of trunk or as large as a rainforest. eastern Australia. Coyotes survive American desert The great horned owl in many different makes its nests on saguaro places because The deserts of southwest USA cactuses, where its eggs they will eat are extremely hot but lots of will be safe from predators. whatever is animals and plants live there. The sharp spines available! Animals avoid the heat of the will put off any day by hunting at night, and egg thieves! plants can survive a long time without any rain. The organ pipe cactus opens its flowers at night. This rattlesnake will shake the rattle on the end of its tail if it feels threatened. The saguaro cactus is the largest cactus in the USA. 36
Under the sea Reefs are home to The banded sea all sorts of fish. krait is a type of Coral reefs are amazing underwater sea snake. structures formed by living creatures. They grow in warm, shallow waters in This type of coral is tropical regions and are home to a called table coral. dazzling variety of life. A stinging ...while clownfish anemone provides scare off fish who a safe haven for want to eat the clownfish... anemone! Mountains Golden eagles have incredible eyesight for spotting prey from great distances. The Himalayan mountain range in Asia is a tough place to live. Animals and plants have to cope with extreme cold, storms, and living at great heights. Snow leopards are Pikas are hunted incredibly rare. They eat by golden eagles. wild sheep and goats. Wild goats, like this Mount Everest in the markhor, munch Himalayas is the world’s plants and spread highest mountain. seeds in their dung. 37
Irnasiidne aforest Emergent layer Tropical rainforests are made up The tallest trees can reach of four different layers. Each one heights of up to 55 m (180 ft). provides a home for different That’s a long way up! types of animals and plants. Canopy Tree frogs rarely leave The canopy is a thick layer the canopy. of treetops that is home to animals, birds, and lots of Sloths move climbing plants. very slowly. Understorey Pitcher plant Short trees and shrubs provide cover for small animals as well as predators such as jaguars. Forest floorOkapi This is the darkest part of the rainforest. It’s muddy and covered in leaves that have fallen from the trees above. 38
Scarlet macaw Sunlight in layers Blue morpho butterflies are Each layer of the rainforest gets found in the different amounts of sunlight. emergent layer. Emergent layer Gibbons are Full sunlight a type of ape Canopy from Asia. Lots of sunlight Understorey Sunlight and shade Forest floor Mostly shade The toucan’s beak is so Toucans use colourful. Why not try to their beaks to grab fruit paint a picture of it? and nuts. Snakes slither between the layers. Chameleons can Jaguar make their skin change colour! This gigantic An teater flower stinks of rotting flesh Leafcutter ants to attract flies that will spread its pollen. 39
cClhimaatne ge Climate is the general weather conditions over a large area. It changes naturally over long periods of time. However, recently Earth’s climate has been getting warmer faster than usual. Polluted planet Fossil fuels, such as oil and coal, are the buried remains of ancient plants and other living things. Burning them releases harmful gases, especially carbon dainodxidpeol(lCutOe 2o),uirnptolatnheet.air. These gases heat up Carbon dioxide is called a Factories “greenhouse gas” as it traps the Over the last few Sun’s energy in our atmosphere, hundred years, many coal-burning factories heating the planet. were built. They pumped more CO2 into the atmosphere. Motor vehicles Cars and lorries use diesel and petrol as fuel. These fuels are made from oil. Burning them releases CO2 into the air. Chopping down forests Trees soak up CO2 like a big sponge. By chopping down forests for timber or to make farmland, we take away one of the best ways to remove CO2 from the air. 40
A greener future Experts predict that by 2040, one-third of all cars Scientists and engineers now look for ways to bought will be electric cars. make energy that do not burn fossil fuels. They are especially interested in energy sources that Electric cars won’t ever run out, such as wind and sunlight. These cars run on rechargeable batteries, rather than petrol. Because of this, they Solar panels don’t pollute the air with CO2 and other Solar panels absorb harmful gases. sunlight to make Effects of electricity and heat. climate change Trees A warmer climate can lead to extreme Planting trees helps to fight weather. Big storms are becoming climate change because plants more common, often causing flooding. absorb CO2 from the air. They Climate change is also melting the sea use the carbon to make their ice covering the Arctic Ocean. own food and grow. Every tree makes a difference. This little one could live for 200 years! Flooding Wind farms Melting Arctic sea ice Wind turbines make electricity from wind power rather than by burning fossil fuels. Groups of turbines are called wind farms. 41
Microlife Dust mites There are billions of very tiny living These blobby creatures eat bits things around us, on us, and even of dead skin found in house inside us! Our eyes can just about dust and mould. They’re very see some of this microlife. However, hard to see because they’re tiny we need to use a microscope to see and almost see-through. how amazing they really are. Dust mites have Hair lice Hair lice have two many little hairs, antennae, or feelers, called setae. These tiny insects live in hair, on their heads. usually children’s. They bite the scalp to feed on blood. However, apart from causing itching, they are not harmful. Hair lice glue their Tardigrades have four eggs, called nits, pairs of chunky legs with to shafts of hair. tiny claws. Their name means “slow stepper”. Tardigrades Also called water bears, these little animals live in wet places, such as mud. They are super tough, can survive in space, and can go without food and water for more than 30 years! 42
Plankton Plankton are living things that drift about in oceans, rivers, and lakes. Some are microscopic, or really tiny, but others, such as jellyfish, are much bigger. Many sea and freshwater animals eat plankton. Bacteria Bacteria are microscopic living things, made of just one cell each. They are much smaller than the cells that make up our bodies. In fact, our bodies contain billions of bacteria! Some of these bacteria are useful, supplying us with important nutrients. However, others can cause nasty diseases. This bacterium has started to split into two new cells. Viruses Viruses are tiny things that can make people, animals, and plants ill. They enter cells and then make copies of themselves. Flu, colds, and measles are all caused by viruses. 43
Tbhoe dhuyman Large intestineBrain Our supercomputer, the brain, controls our An adult human body44 thoughts and actions. contains 206 bones, 650 muscles, and trillions of tiny The human body is made up building blocks called cells. of systems. The nervous system Each part of the body has controls how we think, feel, and a different job to do, but move, the immune system fights they all work together sickness, and the digestive system to keep the body running smoothly. turns food into energy. Lungs Organs Lungs transport Heart Our body is made up of lots of oxygen from the different organs. The organs that air into our help us digest food include the bloodstream. stomach, the liver, the intestines, and the kidneys. Even our skin X-rays are Kidneys Liver is an organ! not just used to ach Stom look at bones, they The heart pumps blood also scan luggage inStemsatilnl e around our body. at airports. The liver has more than 500 jobs. We wouldn’t be able to survive for more than two days without it!
X-rays allow us Muscles to see what our bones look like. Muscles are the stretchy cords connected to our bones that Bones allow us to move. Some muscles work without us having to think Newborn babies have more than 300 about them, while others are bones. By the time we reach adulthood, controlled by our brain. some bones have joined together to make 206 in total. They fit together to Skin form the skeleton, protecting our inner organs and keeping us upright. Skin is the waterproof outer layer that stops us from injuring or infecting Blood Veins and arteries our insides. It is the biggest organ are blood vessels in the human body, making up that carry blood to 15% of our weight! and from the heart. 45 The heart pumps blood around our body through tubes called blood vessels. Blood transports oxygen to parts of the body and fights germs.
Two sides The front part of the This part of the brain is brain is all about your in charge of how we move The brain has two sides. personality – how you our bodies. It can tell us The left side controls the behave, and what you to walk, run, or dance! right side of our body, like and don’t like. while the right side is in charge of the left side of Planning the body! movements The more wrinkly Left Right Thinking and your brain, the Movement personality smarter you are! ? Speech Hearing This part of our brain allows us to speak to each other. Think You figure out what Memory different sounds This part of your brain is about it are in this part of where you keep all of your the brain. memories, like the first time you rode a bike or Your brain may look like a big wobbly your last birthday party. ball of jelly, but it works like an amazing supercomputer. It sits in your head and allows you to see, hear, talk, move, feel, think, imagine, and remember. 46
Every time you touch Artificial intelligence something a message goes to this part of the brain. Computers can be taught to think and make decisions like humans. This is Being able to understand our called artificial intelligence (AI). Mobile surroundings helps us to make phones use AI to help answer any good decisions about how to questions you might have or tell you move around. what’s in your diary. Touch What’s the weather like today? Understanding emotions, like happiness or sadness, helps us to respond well to other people. Awareness of space It’s raining. Take an umbrella! Emotional Making understanding images Seeing Our brain receives information from our eyes and makes sense of what we’re seeing. Coordination Nervous system This bit of the brain helps us to move smoothly. It’s We have a huge network of useful for things such as nerves inside us, which link the walking and writing. brain and the spinal cord to the other parts of the body. The spinal cord carries messages to and from the brain. 47
The senses Sight A lens inside each of Our senses let us understand the world our eyes focuses light around us. They tell us what’s safe and what’s onto the back of the dangerous, and let us see and hear each eye. There, receptors other. Special receptors in our bodies help sense brightness us to sense our world. and colours. The main senses Sight, smell, touch, taste, and hearing are our five main senses. However, we also have other senses that help us survive. Smell Tiny receptors inside the nose pick up many different odours. Smell is closely linked to the sense of taste. Touch Taste The skin contains Taste buds on the top of the many receptors tongue sense five different that react when flavours. These are salty, sweet, we touch things. sour, bitter, and a savoury flavour called umami. 48
Search
