CONT ENTS 5 Notes for helpers 6 What is light 7 What is sound 8 Using this book 10 Scientist kit Can you see sound Find out on page 25 32 Glossary and Index Which travels faster light or sound Find out on page 27 Learn all about light and sound including how light travels and why we hear sounds Experiment time 12 Hand shadows 14 Ray of light 16 Through a lens 18 Rainbow colors 20 Changing colors 22 Picture flicker book 24 Seeing sound 26 Light races sound 28 Musical box 30 Blow some music What happens when a light ray hits a mirror Find out on page 15
Notes for HELPERS Help and hazards Help needed All of the experiments are suitable for children to conduct but they will need help and supervision with some This is usually because the experiment requires the use of scissors for cutting These experiments are marked with a Help needed symbol Read the instructions together before starting and help to assemble the equipment before supervising the experiment It may be useful to carry out your own risk assessment to avoid any possible hazards before the child begins Check that long hair and any loose clothing are tied back Check that sharp objects such as scissors are put away safely after use Extra experiments Also try You can also help children with the extra experiments in this book or search the Internet for more similar ideas There are hundreds of science experiment websites to choose from www lovemyscience com This website is packed with simple fun experiments for children to enjoy www sciencebob com experiments index php Engaging science experiments with clearly explained instructions will keep kids busy for hours www sciencefun org kidszone experiments You will find lots of entertaining and informative experiments on this colorful interactive website Publisher’s note to educators and parents Our editors have carefully reviewed these websites to ensure that they are suitable for students Many websites change frequently however and we cannot guarantee that a site’s future contents will continue to meet our high standards of quality and educational value Be advised that students should be closely supervised whenever they access the Internet 5
What is LIGHT Light is a type of energy that you can see and it is essential for all kinds of things We need light to grow food and to be able to see around us In earlier times people used fires candles or oil for lighting Now we make our own light with electricity or gas Sun Hot light Light is usually produced by a very hot object such as a light bulb or fire and heat is released The sun is our main source of light Its rays travel through space and reach us as heat and light energy How light travels Light travels in straight lines called rays Light rays change direction if they are reflected off or pass through an object or substance but they still remain straight Viperfish Refraction When a straw is placed in water it looks as though it is slightly bent This is because light rays bend when they pass through water This bending of rays is called refraction Reflection When light hits a very smooth surface such as a mirror it reflects bounces off the surface If it hits a mirror at an angle it is reflected off at exactly the same angle The eye receives a reflection of the image Light rays bounce off the mirror 6 Cold light Some animals produce a kind of light that gives off no heat Fireflies and glowworms are insects that can make parts of their bodies glow with light About 1,500 different deep-sea fish give off light Actual object
What is SOUND Most sounds you hear from the whisper of the wind to the roar of a jet are actually moving air Every sound originates with something vibrating This makes the air vibrate too and the vibrations in the air carry the sound to your ears The vibrations that carry sound through the air are called sound waves Inside the ear Outer ear How do we hear sound The outer ear funnels sound waves into the ear From there sounds pass through a tube called the ear canal to the eardrum Sounds make the eardrum and tiny bones in the middle ear vibrate These bones pass the sound to the cochlea in the inner ear where nerve cells change the vibrations into messages that travel to the brain which recognizes what we are hearing Sound measurement The loudness volume of sound is measured in decibels dB A quiet sound such as whispering is 20 dB A very loud sound such as a plane taking off is 120 dB Tiny bones Cochlea fluid-filled chamber Eardrum Ear canal Rustling leaves 10 dB Talking 40 dB Thunder 100 dB Atom bomb 210 dB 7
