How it works : Science experiments

NEW robert winston

Get up Mix colourful
close with chemicals
particles

Heat up your
projects

BOOK OFExperiment Elements
with ice explained

SCIENCE

EXPERIMENTS

Everything you need to know to bring science to life

Learn about 10
the power
brand new
of light
experiments

inside

Use
magnetic

force

Discover
the science
of colours

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BOOK OF

SCIENCE

EXPERIMENTS

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Disclaimer
The publisher cannot accept responsibility for any unsolicited material lost or damaged in
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Pages 4-137 and 152-158 of this bookazine are published under licence from Dorling Kindersley
Limited. All rights in the licensed material belong to Dorling Kindersley Limited and it may not be
reproduced, whether in whole or in part, without the prior written consent of Dorling Kindersley

Limited. Copyright © 2016 Dorling Kindersley Limited. A Penguin Random House Company.
The content in this bookazine has previously appeared in the Dorling Kindersley book
Science Experiments, published 2011.
ISBN 978 1785 462 047

Part of the

bookazine series

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FOREWORD

Visiting science museums, watching science on TV, and Science explains how the world works, and how life exists.
inspiring teachers were important to my becoming a scientist. Scientific discoveries have made our lives healthier and longer
But reading books about how to do experiments and then actually than ever before. Science give us understanding about where we
doing them was the biggest thrill. I still remember my excitement come from, how we grow in our mother’s womb, how our body
when I was 10 growing huge coloured crystals in the kitchen – functions, and how we can avoid illness. Scientific knowledge
without any help beyond a few instructions. A few years later, affects every aspect of our lives and our understanding of
there was this extraordinary sense of triumph when I tuned into the plants and animals around us. And science starts with
the BBC with a radio set I had made entirely on my own. The experiments. Doing experiments, seeing what happens as we
programme was boring and the signal very crackly with an explore the nature of things around us, is the object of this book.
annoying whistling sound. Indeed, much of the time I couldn’t
understand what was being said through my crude, uncomfortable I hope you will enjoy these experiments. Many were those I
headphones. But I knew what I wanted to do in future. I’ve never did when I first got interested in science. Some of them were
admitted this previously – but I feel embarrassed that, when asked dramatic or exciting, others made me think. Occasionally they
by an ageing aunt at a party what I expected to be when I grew made a real mess – which didn’t always please my mother. Some
up, I replied “a famous scientist”. experiments didn’t work at the first attempt and required practice

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and patience. But the experiments here tell us about the nature takes precautions not to damage their eyes, and when working
of things around us – or how we have improved our lives by with fluids it is sensible for you to wear eye protection such as
harnessing energy and by making radios, cameras, and machines. goggles. And where there are instructions in this book about
taking special care, remember not to neglect them.
Most demonstrations in this book require simple, cheap materials.
Occasionally you may need an ingredient from a chemist, or I am sure you will enjoy these scientific experiments. And who
a hardware store. A very few items may need to be found by knows, they may intrigue you so much that, like me, you end up
searching online using a computer. wanting to be a scientist.

But remember: all scientific experiments occasionally have
unexpected results or cause surprises. All good scientists take
great care to avoid doing things that are unnecessarily dangerous
or that might damage other people. So when enjoying these
experiments, it is a good idea to use rubber washing-up gloves or
other protection for your hands. Everybody working in laboratories

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contents

10 THE MATERIAL 26 Slime time 42 FORCES AND
27 Fantastic plastic
WORLD 28 Butter it up MOTION
29 Holding it together
12 Changed state 30 Cycle centrifuge 44 Dome, sweet dome
13 Ice cloud 31 True colours 46 Launch a bottle
14 Ice bubbles 32 Oxidation station
15 Mega bubble 33 Rotten apple rocket
16 Crystal creation 34 Elephant’s
18 Bigger bubbles 48 Gravity-defying
20 Liquid layers toothpaste
21 How dense is it? water
22 Float your boat 36 Turn water pink
23 Dunking diver 37 Cabbage indicator 49 Puzzling pendulums
24 Fizzy fountain 38 Violent volcano 50 Air-resisting eggs
40 Copper plating 51 Balancing act
41 Spruce up silver 52 Fly a dart
53 Float a glider
54 Balloon hovercraft
56 Rubber band

drag racer

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58 Ice water 72 ENERGY IN 86 Up, periscope!
88 Two-tube telescope
can crusher ACTION 90 Cardboard camera
92 Matchbox
59 Flowing fountain 74 Convection
60 Eggs-periencing microphone
currents
air pressure 94 Tap out a tune
75 Set up a solar oven
61 Under pressure 76 Move metal 96 ELECTRICITY
62 Suck it to ‘em
64 Make a soda shoot through ice AND
66 Blast a two-stage MAGNETISM
77 Chill out!
rocket 78 Full steam ahead! 98 Charm a
80 Split a sunbeam
68 Hydraulic lifter 81 Hosepipe rainbow paper snake
70 Weightlifting 82 Make a
71 Spreading the load 99 Tiny lightning
spectroscope 100 Detect a static

84 Glow-in-the- charge

dark jelly 102 Fashion a flashlight

85 Glowing plants

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104 Lighten up! 118 THE NATURAL HOME
106 Salty circuit EXPERIMENTS
107 See a citrus current WORLD
108 Tune in to a 140
120 Under pressure
homemade radio 121 Wind whizzer Nine home
122 Create a cloud experiments
110 Make a metal 124 Sow a seed
126 Chasing the light 144
detector 127 Starch test
128 Split colour flower Make a
112 Microscopic 130 Revive a carrot zoetrope
131 Absorbent eggs
meteorites 132 Rapid response 146
134 Drum up some DNA
113 Magnetic breakfast 136 Grow your Making
114 Build an hot ice
own germs
electromagnet 148

116 Make a motor Penny drop
experiment

150

Mod a Nerf
Maverick

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How to use this book safely and get the most
from the experiments – an important note for
children and adults

This book is packed with amazing science experiments – some Every experiment includes a clear list of everything you
are very simple, while others are trickier. Have fun reading this will need to do it. Most will be stuff that you can find around
book and trying the experiments for yourself, sensibly and safely. the house. If any specialist equipment is required, you will find
We’ve marked with symbols where you need to take extra care, advice on where to get it in the “Top Tips”. These also give
and where you must have an adult to supervise you. We have handy tips on how to get the most from the experiments.
aimed safety advice at younger readers; older readers may have Every experiment includes a “How Does This Work?”
experience in such things as heating liquids or hammering nails. feature, which explains in simple terms the scientific
principles involved.
Take special care with any experiments that use an electric
current. If an activity involves food to be eaten, make sure all your The authors and publisher cannot take responsibility for the
utensils and surfaces are clean. For experiments with moving outcome, injury, loss, damage, or mess that occurs as a result
parts or chemical reactions, it is advisable to wear goggles. of you attempting the experiments in this book. Tell an adult
In most cases it is obvious why you have to be careful, but if before you do any of them, carefully follow the instructions,
there is specific safety advice you need to know, we’ll tell you. and look out for and pay attention to the following symbols:

A guide to the time the The level of difficulty You should have Warning!
experiment will take. of an experiment, from an adult present.
green (simple) to red Pay extra attention when
(quite tricky). you see these symbols.
You will find important
advice on how to carry out
the experiment safely.

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1 TheWMoartledrialEtschwvttheheuaeerdpyymyaatmphitosoeiftanmrrtgmyots.eftaChartthanthcietdsehrmybaoaoontinshuogdtekescrsttaoehtnitxenthphsyrweleoapeaugianyglroi,sshtwpicmirttilneheacgdesdaiigcroneatfu,scownahfodnhafmedintcrhaghscetetotiaSetnisnurits,dnrcfomi.anrTlolgalthmehdeodeef.

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Changed State YOU WILL NEED:
Magisnaodcssathgloliaetfssd.tahWdeicshotmeilldnlaatsyttuioeorurnfaobacnoneidEl ilaticqrtatuunhirdnbeswexibasuattssecerkidnitinttothtuorprenauesrliisfqinytuatwiotdea.asTteg–hrai.ssso,tlebidcu,htliniqfiuqthiudee,
Salt
240 ml (8 fl oz) water
Old saucepan with a lid from a

bigger pan
Dish

15 mins

1 Mix four tablespoons of salt with SCIENCE AROUND US
the water. Stir until the salt has
dissolved. The salt molecules Plasma
are now evenly mixed with the The fourth and inal state of matter is plasma.
water molecules. A mixture like Plasma is similar to gas, but unlike gas it is so
this is called a solution. hot that it is ionized – the heat tears electrons
off its atoms. Aurorae, like the one below, are
States of matter WARNING! 2 Pour the solution into a saucepan. Set
the saucepan on the hob or a camp stove. caused by a solar wind (a plasma) from the
MstohsoUniuonsirntgeeosarot,shvtsheefuarenclohl hptmeghaalaoenttsvhwicetsehlsaotpetustaeorsennralhy.ehuadaacnsenoddpgflfeaomannhsaeolikdte. Place a dish beside it and angle the pan lid Sun reacting with Earth’s upper atmosphere.
so that it is sloped towards the dish. Ask an adult Beautiful colours lash in the sky, normally
to turn the heat on and let the water simmer. close to Earth’s poles.

The water vapour The salt is left in
cools as it hits the the pan after the

lid and changes water evaporates
ba ck into a liquid

3 When there is no water left in the
pan, turn off the heat. The water
has turned into water vapour (a
gas), but changes back into water when
it hits the saucepan lid. It trickles down
the lid into the dish. The salt – a solid –
is left behind in the saucepan.

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Ice cloud YOU WILL NEED:

Laiiqr udiidsssoalvneddgiansiet.sWohfteenntgheetwmaitxeerdisufprotzoegne,ththeer.aCirofldorwmastbeur bobftleesnthhaast Two plastic food containers with lids
make the ice cloudy. Water
Kettle
Freezer

1 day

Tap

1 Half-ill the irst food Boiled SCIENCE AROUND USOdd water
container with cold tap Usually, a liquid takes up less space
water. Snap on the lid and Boil some water and leave it to Label the containers so as it cools down and even less
give the container a good cool. Pour it slowly down the that you know which is space when it freezes, because its
shake for 30 seconds to molecules move closer together.
mix air into it. 2 side of the second container. But when water is cooled it takes
3Boiling the water irst and then up less space only until it reaches a
pouring it slowly like this reduces which. Put both containers temperature of 4°C (39°F). If it gets
colder than that it starts expanding
again, making it less dense. This is
why ice loats on water.

the amount of air it contains. of water in the freezer and leave

them overnight.

TOP TIP

celoImxI(ftumcprtdaoyehpkynrefu.eitimlrIawtfibetienyiaorensoittnstehulgorimnbhttilsniahtoghveocyheekfotwsumwanarooawitnatfetearewircetrrfeaeoaimrlrrslsikosfi)tgio.ltwhthhkeateirsrl,dl. The boiled water
with less air in it
makes clearer ice

Air makes 4 When the water has frozen solid
the ice cloudy remove the containers from the
freezer and take the ice out.
The ice made from the shaken water
contains lots of tiny bubbles, making
it look cloudy in the middle.

how does Molecules are closely In a liquid the molecules Gas molecules
this work? packed and tightly are loosely linked and can are far apart and not
linked in a solid slide past each other linked to each other
TWatlmagihhnqaheoseduseulisemdmnbboc,soayoluietcldorlaeveekuncebsuciunhenflneltecteyut,oaosialyatmaltooplahyefulaeissqaircytotuaaswlcaiionddlaniillq,lnidradeiurntemivsiatddaerobm.cretvseIhhofeteceilyigoetnptoshhmcaauteubsleylskotpesoeiepsrlaelioaainvdpcccggi.ebhkahpsreseoasod.attiBhaetntineoyntmrdgg–coaeotitntrtuhosehdreleninr.ag
Low temperature High temperature

Heating or cooling substances 13
changes their state

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ice bubbles YOU WILL NEED:
FmfPrruooetmzlteistanittsocdoatolhirdebestoontne’atsdmgtiaobasxykiiednmeaaawpkisrienoctgcapetlulhsedisdsdkbldneuro.byIwtbcinlcyheaab,snrbseguuwetbs.lwidmihraeetcniotlniyt.
Glass or mug
1 Use kitchen tongs to place Kitchen tongs
a couple of lumps of dry ice Dry ice pellets
in the bottom of a glass. Water
2 Use a jug to pour some Jug
cold tap water into the glass. Liquid soap or washing-up liquid
The water melts the dry ice,
causing carbon dioxide to ill the 20 mins
glass and spill out over the top.
WARNING!
Sublimation 3 Add a few drops of liquid soap
or washing-up liquid to the glass. ocDgrobyaerfnayosxrtreupiaieecterlionenehzssoeeaxkiisuorrpnin.gnasd–D,honsisioft.daocnsWwsno’tntdoailheldplrnecvneutdneohodtruciatititlopntdbciuiinecahtblkdnactlkohnaeicawtegnpaiuretfutdprsiscgiadewothmgoltaidetaanhge
After a few seconds a tower of the door off!
bubbles will grow upwards from the
how does glass. It is safe to take a handful of
this work? the bubbles and play with them.

AeaFpttaistahgaomwsqorerlueecrigeurlmaqamebisheqiatpuhaclspseteiuorimtekhusodreedeitaldeurlrytsahriiehtaaor.dbsteetoattiAiht,suorduednnostnadrnlr–rlaeyutyenoymhd.hnnpsrofloiCiiEecnonecyalnoeeaadglielestpfinorrEhqtcibtsri-oftoftehaue7urfoouter’hrsi8leisaodntgeneseahºxpgsahtuCdassitoesiiomrttitsrttoetast(hoaih-pgmasntxaa1ueergtkhiost0meduopr.eat.tc9sreavWlssoyFaneaºse.FsrlnonnuhtbietTqhua)drooreo.sheebputusnIushla.iitlaiogscdidunatWmrcmlhah,ebdtiniaqsreeihlaettbnpiuftiosmkesoornoaisnneduagmheeansuox,breeoytsbiowgttostdolhsdhmilatmvneusteesaeactoyaarea.hnsurissdeecrledmess, Washing-up
dioxide gas form bubbles. liquid

Dry ice
p ellet

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mega bubble YOU WILL NEED:

Once you’ve made a lot of small bubbles, why not try making Bowl
one enormous dry ice gas blister? You can make one with a Cloth bigger than the bowl
Water
bowl and some soapy water. Washing-up liquid
Cup
2 Half-ill the bowl with water SCIENCE AROUND US Dry ice pellets
and use kitchen tongs to Kitchen tongs
drop a few lumps of dry ice
into it. Let the bowl ill up with 10 mins
carbon dioxide gas.
Chill in the air
1 Add lots of washing- Sublimation can also occur when the change
up liquid to water in of states happens so quickly that there is not
a cup and soak the enough time for a liquid state to form. On a
cloth in it. frosty morning, when water vapour in the air
hits a cold surface it is cooled down so fast
that it turns straight into solid ice crystals
without becoming a liquid irst.

3 Wind the cloth into a soapy rope,
but don’t squeeze the water out.
Lay the cloth along one edge of
the bowl and then pull it across the bowl,
from one side to the other, to form a
soap ilm over the top of the bowl.

TOP TIP 4 A soapy bubble forms and
grows bigger and bigger.
onebmlDixunpirbexyevbtsuerilceuiurrmeepyswepicbnninlaliieglegtnep,.rtfsodthrFbho.pseoeeFmrtbbpoowbeuurpebfbaratoschebsgrthehleeesraitnem1ismrtg8soeehu-.indxgualgttapfssuro,rboglietrqumrrotuybhwibdelne When the giant bubble
inally bursts, the carbon dioxide
gas spills out. 15

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crysctraelation YOU WILL NEED:

Aacnrraceytrsuyotrsaratdllsaley,lr,iessbuduactishtnohliaaisdsermexdppaiaeetmerairmtoieanedldnmstth,amrdteaaeekko-eedfsiambctirolelyimnossntsaisoalsnnoaadflpmppyeaeoatalterrescorunvtle.eorsSnfotioghmrhamett. Clean jar
Hot water
Pack of powdered alum
Two spoons
Pipe cleaners
Paper clip
Pencil
Paper towel

1 day

Crystals TOP TIP

SCIENCE AROUND US arpeoSpDttuoahotpwsheensedrbobieumceotrmrstta.yhatIrstaskpmtlmteulaeaitmllac,sdtyaehlayosseanrtlttdspoahoooxlepuliwocyhbm.oaedakreprcmerofaotaolalrcersiadehlsu. m
SCIENCE IN SECONDS
1 Pour hot water into the jar until it 2 Bend your pipe cleaner 3Hook the other end of the paper clip
is three-quarters full. Drop in one into whatever shape you around the pencil and lower the pipe
tablespoon of powdered alum at like and then twist the cleaner into the solution so it is
a time, and stir with another spoon. paper clip so that it forms an “S” suspended in the middle of the jar. Rest the
Keep going until the solution is shape. Hook one end of the paper pencil across the jar’s neck. If the pipe cleaner
saturated and alum begins to clip around the pipe cleaner so touches the bottom or sides, your crystal will
collect on the bottom of the jar. that it is held irmly in place. not grow properly. Leave it overnight.

Natural crystals Crystal pops
Many of the largest natural crystals ever discovered Sugar is a crystal that can be used to make some tasty
were found in 2000 in the Cave of the Crystals, Mexico science! Simmer eight tablespoons of sugar, 120 ml (4 l oz)
(below). Scientists found massive gypsum crystals of water, and a tablespoon of your favourite squash in a
11 m (36 ft) tall and 4 m (13 ft) wide that had taken small saucepan until the sugar has dissolved. Boil the liquid
millions of years to form. The cave is deep underground, for a minute before pouring it into small paper cups with a
with a constant temperature of about 50ºC (122ºF). lollipop stick in each. Cover the cups loosely with clingilm
This provided the mineral-saturated water in the cave and let them cool for at least a day. When you return, most
with the perfect conditions for crystals to grow. of the water will have evaporated, leaving you with perfect
sugar-crystal lollipops that you can eat.

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TOP TIP You can use the
paper clips to hang
PtoYoufottbhuayyegloucarusmaodronwdlcsuicnroetyogilvousloefnttouainoforlrnbdioyniagomcanguodertflohrrcie!uetrsrywsihnstitlgajlaarlrts. a few together and
make a crystal mobile

Alum crystals form 4 When you check the
on the fibres of mixture the next day, alum
the pipe cleaner crystals will have formed
on the pipe cleaner. Take the
pipe cleaner out of the solution
and dry your crystals on a paper
towel. Why not make a few and
use them as decorations?

how does The atoms in an alum
this work? molecule are arranged
in an orderly 3D pattern
Iidcdmfcnoicnreirtvrsyowehtyetssevaehsarotritynteantmilaenvilghgwlrieggsnahfadwreavtmtoth,diseeilwnoailtrtt,b.trfsihocebmyIatoborrrsmteetgynehparwtaeraaarckenaacdtrisptndctyeuhreegstaaassrfatcolppatbtlathyrileaeneseilctdgc.tiouteaaTttftrtloluohnehtutohses,amdteelhtgiiessnesprmthasothhoavoopiweanwiplinsvpp,ewedgoeeemreaa.ol.licoretdlAfM’elsssuetsrdhsotpammitermansheqompoeeciulnarlaero.eisyelcccucnosrkeumaudlteulallfe-sertolcsis–oairhdasnnantiatshhdprcsbeeeeooedalovlluesmd

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B B B&U\VWDOV LQGG

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Bigger YOU WILL NEED:
bubbles
Bucket
BatYmotuotabsrukabhecclreiastnsinokthanmter,heaoirekrvsebseuuurbrybrfuafbabtclhecbeie,lnsebstlsuaetltynaroetsshnritoseganoaa,lofinbrndleiignqtewsutviiidemdeeenewn.sbitttoyhhpeuassliiritqnhtugirsiadapfrmbpoueombdlebhiclneausplmiedpsieex:nttrtihinheagest. 120 ml (4 fl oz) washing-up liquid
1.2 litres (40 fl oz) water
Glycerine and sugar
Clingfilm
Wooden rod or length of dowel
2-m (7-ft) piece of string
Metal washer

2–3 days

Surface tension 1 In a bucket, mix the washing-up 2 To make your bubble wand, take 3 Loosely tie the string to the stick
liquid with the water. Add two a wooden rod or stick and tie the about 20 cm (8 in) from the string’s
tablespoons of glycerine and string tightly at one end. Thread end. Moving this knot to and fro
ive tablespoons of sugar. Cover the string through the metal washer. This along the stick will allow you to adjust
the mixture with clingilm and leave weighs the string down and holds it the size of your bubbles.
it to settle for a few days. open when making your bubbles.

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SCIENCE IN SECONDS Walking on water
SCIENCE AROUND US Surface tension makes molecules on
Milky madness the surface of water “stick” to one
Drop some food colouring onto a bowl another. Some insects, such as
of milk. Dip one end of a cotton bud in pond-skaters, can walk on this fragile
liquid soap and then hold it in the centre surface. They can do this because their
of the milk, just touching the liquid’s long hairy legs spread their weight over
surface. The food colouring races away a wide area. They press so gently on the
from the bud and swirls around. The soap surface that they do not break through it.
weakens the surface tension of the milk,
but it does so more in some places than
in others, causing the colours to zip
around and make patterns.

4 Tie the loose end to the TOP TIP how does
irst knot you made to this work?
complete the loop. pgotrliymvIaofcekppmyereeoonrisrxiurilngtytaaehwutnltrhoia.estrnnTtovtgthoouishitsglbcieumhoriagseuetvewbhsetbeeo(tauctmhhtsbaeipbluicexrlbskteaeeuu)ssabra,ttdenbhit.dle’es
Molecules inside a liquid attract, and are
attracted by, all of the molecules around them.
Those on the surface have no molecules above
them, so they attract the other molecules on the
surface more strongly. These stronger bonds
produce a skin-like effect called surface tension.

Surface bond Molecule at the surface

5 To make giant In a bubble, surface tension pulls the liquid
bubbles, soak the surface tight while the pressure of the air stops
string of your bubble the bubble collapsing. The soap spreads the
wand in the mixture. Pull it liquid layer evenly, so there are no weak areas.
out slowly and swish it Glycerine and sugar make the bubble stronger
through the air. by slowing down the evaporation of the water.

Air pressure
stops the bubble
from collapsing

Surface tension
pulls bubbles into

a tight, round
shape that holds

the air in

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B B B%LJJHUB%XEEOHV LQGG

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liquid YOU WILL NEED:
layers
Tall glass
Lmodibqeixjuneiswdcestilsltchsdaaernnpoafptlrhpoaeeatmtdeasionneudlwtveswilislni.tskhin–tkhtewundoteiolnrtshmeesoytrmaetelitqehuteiadbsloiqtthtuoaidmt dm. oAonnr’yet Water
Cooking oil
Treacle
Food colouring
Selection of small objects

30 mins

1 Pour some water into 2 Drop in a selection of
the glass and add a few solid objects and give
drops of food colouring, everything a good stir
then pour in equal so that it is all mixed up.
amounts of treacle
and cooking oil.

DENSITY how does Objects sink
this work? until they

Tm(iddabimsamihttimeuisrvseigaeiptcidovsdkmdehmsdouiemnnemollnmoeudgnmlatlae.msseasiolacOitctlsteoftsuybutie,)nlshsl.luersoiepesTbttsoifshash,ydctaectthetlpeohnvoheesnaoaasofioibsclmztleuenubeekeagadmotjsetreoshwoutedtecgtfhnlel.titaeidiqetenitAogrtesuonthgdrhonilfemediettssqmhlrt,.nuy,eohueaWsbsaelipmlredioitsetqaactsy’t.setcuia,pusteTrkinypdladrsreieoeccaenismtdbaueecnssaceeostisioinsloctidlneitemmdagythcfathueaehoptukashtrtewllehhsyeeeaseisnpru,gaprt. meet a liquid
that is denser
than they are

Sugar-coated
chocolate floats

on the trea cle

3 Leave the mixture
to settle for about
30 minutes. The
treacle settles on the
bottom, the oil rises to
the top, and the coloured
water sits in the middle.
The objects sink and then
loat in the places where
the liquids meet.

Treacle Water Oil Metal washer sinks
to the bottom

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How dense YOU WILL NEED:
is it?
Weighing scales
To find out the density of an object, you need to know its volume – Notepad and pencil
how much space it takes up. Finding the volume of oddly shaped Plastic bottle
objects was quite tricky, until Greek scientist Archimedes Scissors
(287–212 BCE) realized that there was a simple solution. Drinking straw
Modelling clay
Measuring jug
An object to be measured (must
be waterproof!)

15 mins

EUREKA MOMENTS 1 Weigh your object on the scales. Note 2 Cut the top off the plastic bottle 3 Push the straw through the hole
down the reading – this tells you the and recycle it. Take the bottom and angle it downwards, using
object’s mass. (Mass is the amount of part and make a hole in it, just the modelling clay to seal the
matter in something.) big enough to it a straw through, gap around it. Position the jug beneath
near the top of one side. the straw and ill the bottle with water
“I have found it!” until some of it runs out through the
The original eureka moment happened to straw. Throw this water away.
Archimedes as he was grappling with the
problem of how to measure the volume of 4 Fully submerge the object in the water.
oddly shaped objects. As he lowered The amount of water that comes out of
himself into the bath, he noticed the water the bottle into the jug is the object’s
level rising. He realized he could ind the volume. You can use this to ind out the
volume of any object by measuring how object’s density by dividing the mass by the
much water it displaced. Excited by his volume. If the mass is 50 g (1.8 oz) and the
discovery, he shouted “Eureka!” (meaning volume is 25 ml (0.8 l oz), the density of
“I have found it!”) and was so happy that the object is 2 g/ml (2.25 oz/l oz).
he ran through the streets without putting
his clothes back on!

Volume of water Object displa ces
displa ced is equal some of the
water
to the Object’s
own volume

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FLOAT BOAT YOU WILL NEED:
YOUR
Marbles
Htphaeovbuebslaeynsodiunskosef?vteIotr’nsnawellostnocdadenorefwdloiathht odowennwsaiatytse. hripwhweneiaghtiinngy Glass of water
Modelling clay
1 Drop a marble intoFloating and sinking 2Take the ball of modelling Bowl of water
a glass of water. It clay and press it out into a thin
sinks. Next, drop a SCIENCE IN SECONDS sheet. Then mould it into the 5 mins
tightly rolled ball of shape of a boat, making its sides
modelling clay into the as high as possible. Elevating eggs
water. It will sink, too. A fresh egg sinks in water, but you can
make it loat by changing the water’s
density. Add salt to the water and stir
gently to dissolve it. Take care not to
crack the egg. If you keep adding salt,
eventually the water will contain so
much that it becomes denser than the
egg, and the egg will loat to the surface.

how does How many 3 Put your boat into a bowl
this work? marbles can of water. The clay now loats
you add and will even support the
Tatacnlishdwebnhrloqebaeesuseawuyosnibdtsdma.esaibaefetsTirtuasmtnl,.hehyslerislWtebeehleeiofndslaxhrvepfhicpnpoeistaearnheknaleinsuatrasna,o-mnmynt.tdtshoodhaWaeesteupehksmshoaees.smddegfoasWqeiwnaawvdmuniheiltaenyaleseeretlloteeileratneihduznsyrnvraees.gt–oldohsneMtdlcfettushathelothimgeadhtenbueyyoeiybes,uvlddseoobebwasiii,rntfuvrnbohtesegttikllsoeheotrahht,bledeflosheietteeohbefastcfldnhaevaohcaosiiteitvaerblusateaeplrb.stuteryrrseetob,a’th.sihatbnpitaThsahttlpnheeoneieseyids before the weight of several marbles.
boat sinks?

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DUNKING YOU WILL NEED:
DIVER
Modelling clay
Divers wear heavy weights to sink and use tanks of compressed air Plastic pen top with no hole at the top
to surface. Expanding the air changes their density. You can see Paper clips
Wire cutters
how by making your own diver in a bottle. Glass of water
Empty plastic bottle

10 mins

1 Roll some modelling clay into a 3Fill the empty plastic bottle
ball and stick it on the end of the with water, and drop in a
pen top. Cut a hook shape out of bunch of paper clips. Drop
a paper clip with the wire cutters and the diver into the bottle as well,
stick the hook into the opposite end and screw the cap on tightly.
of the ball.
4 If you squeeze the
bottle, the diver will dive
to the bottom of the
bottle. When you release your
grip, it rises back to the top.

2 Drop your diver into Can you
the glass of water, make your
and remove bits of diver pick
the modelling clay until up a paper clip?
your diver just about
SCIENCE AROUND USloats in the water.

Sinking subs
Submarines dive by making themselves
denser than water. They do it by opening
valves to let seawater into ballast tanks
inside the submarine. When the tanks are
full, the sub is denser than water, so it
sinks. To rise to the surface again, the
water is forced out of the tanks.

Press the
sides of the
bottle to
make the
diver sink

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Fizzy fountain YOU WILL NEED:
Oacrilbeaiatntodinfgwfiaaztzbeetroaduotthnifi’nutglmse.ifxfB,eubcbut btalyseostuhsectyaarnpturtelhl atehllyecoswltoiaruttreheredtmhwruoaputegbrhymtahodevdioinniglg. ,
Plastic bottle
Jug
Vegetable oil
Water
Food colouring
Two effervescent tablets (containing

citric acid and sodium bicarbonate)

10 mins

density 1 Pour the vegetable oil 2 Add a few drops of food TOP TIP
into the bottle until it’s colouring. For best
about three-quarters results, use a few drops ccovtoteoloTwrognrusyheyerooat,euuiatla.srbhsnYiflnoadeoogmpuusoponheiceltt,inochnaueouesisn.loreadIflonoolaeiasrlldfsitmfvaedetedpaocgddotolseisitnole.dtofeeitrr
full. Use a jug to top up of two or three different colours.
the last bit with tap The colouring will take a few 4 Loosely screw
water. The oil will loat moments to travel through the the bottle top
on the shallower layer oil, before slowly mixing with back on and
of water. the water. watch your izzy
fountain start to work.
SCIENCE IN SECONDS

Pretty patterns
Have you ever noticed colourful, swirly patterns on the surface
of a water puddle? They are caused by a thin ilm of oil (perhaps
dropped by a car) spread on the top of the water. You can recreate
the effect with a bowl of water and a few drops of oil. Each beam
of light is relected off both the surface of the oil and the
surface of the water below. The interaction between
these two relections creates the colours you see.

3 Break the two
effervescent tablets
in half and drop them
into the bottle. They should
start to izz up immediately.

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These blue Carbon TOP TIP
blobs have not dioxide
mixed with the bubble winahagsaePnrrnladeeoidmnnssickgoeuixaidnilatleriitasnubdsbgmotrwlhneeoebiardtfyihocciionctrawxdorwtiibhadngioitetteseahnsgreiatne,axitopasepcnrc..ieothTtrrdaiihocmubetcaelhseicnneetigtsrd
rea ches
water yet the surfa ce

SCIENCE AROUND US Wax lamps
You may have seen lamps that contain
lumps of wax that move through water.
When the lamp is turned off, the cold
wax is denser than water and it rests at
the bottom. When the lamp is switched
on, the bulb in the base lights up and
warms the wax. The warm wax
expands more than the water. It
becomes less dense and loats up
to the top. At the top the wax cools,
becomes denser, and sinks again,
creating lovely patterns.

how does
this work?

Wfirwbtihzslhhozeeee.byunnTsflphttaohhetnaeehfidtrgtzouatzauphbisgnewlehgbabtusrtiusdhbbsesbcbt.alableAerrostbstttoattothlnotetedg.adiWecssiotuhshaxrottefihealdrvreceeameirsgi,ensamtehlstehloe,vserwesbeswhuddibtaeceobtnhneblsserf,eloesotrtbhtpmhhesoaasyponnbbfatouewhnbigelad,bitnobletehiutrls,,oettsthoheat
blobs of water sink back down again.

Bubbles attach to
the water blobs

Effervescent tablets Water blob sinks
release gas bubbles
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slime time YOU WILL NEED:

WcNbaoehluwlaentdtcodaeno,ntehoosifnsEh-linNoqgewulwiisdlhtiqsoulsnimicidaiesen,nbfittleuiswhitdailSlvbsieert.ciIcLaskiauqastuoecidgiNset etduhwoseeutrosamnnlly’othrcfaeloovlnweikf,oetboramudtsotoiofliwdyth.oiteuhrssuhlliemaske,es?,epStuloimllu, etabnisyd Cup
Bowl
Spoon
Cornflour
Water
Food colouring

5 mins

1 Fill a cup with cornlour 2 Keep adding water slowly
and tip it into a bowl. until the mixture turns into
Slowly add some water, a sticky paste. Don’t add
stirring all the time. too much – you probably won’t
need more than half a cup.
Polymers TOP TIP
3 Add food colouring until
your mixture changes nteowFcuosolcboplohdutaedhtcpseiclet.osoPr,ctlhaoraaoenunntsdrdesinoctawgartneiaysnisanusyrnruaofgoarpultfocrrahovescaenskers.iwsmna,iiftntuhdl
colour, stirring it through
until it is all blended in. 4 Pick the mixture up and
see how it behaves. What
how does happens if you squeeze
this work? or pull it? If you throw it on the
loor it will stick together like a
The slime and the plastic are both made of polymers – solid, but if you leave it there it
simple molecules (called monomers) arranged in long will turn into a liquid puddle.
chains. Polymers in liquid form are often non-Newtonian
liquids. When the chains are stretched out the liquid flows, Try adding some
but if you apply pressure the chains stick together. This more cornflour to the
is why your slime sometimes behaves like a solid but at mixture and rolling
other times behaves like a liquid. All plastics are made of it up into a ball. Does
polymers because their chain-like structure makes them the ball bounce?
flexible and strong. They can be shaped and moulded
while soft and then made to set. Your plastic is made
of starch, which contains polymers. The vinegar joins
with the starch to make stronger chains of molecules.
Adding glycerine makes them more flexible.

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Fantastic YOU WILL NEED:
plastic
Old saucepan
Pshaolauwscteticopaimsnasoknteoeysopofautcrheoeswhmnipopssl.atMsvateincrysfarpotlaimlesttmihcisantagersreiyamolsua. dcIteainfsrfouinmsdefdionsiynsoileufvureekrlisyt,ctbhhuientngh. efrroem’s Spatula
Stove or hot plate
Starch (cornflour, potato starch,

tapioca starch etc)
Water
Glycerine
Vinegar
Aluminium foil

1 Mix one tablespoon of starch 1 day
with four tablespoons of water
in a saucepan. Add a teaspoon of
glycerine and another teaspoon of
vinegar and stir until it is all blended.

2 Ask an adult to put the TOP TIP
saucepan on a low heat
and keep stirring. lepyirtTaloeasvoudsoeuhtmuficobtctseaheueeirkesr.teseahApvaneatedasdhfrdniateeyiemmntrsrpogototluoasirumcsesoncketoatlfyi,ecrlkeo,ieatbxmffnwowiugb.ortilillylrelaliefc.mfeyTreairohgwikuneidee,

3 As the mixture heats up, it will
change from a cloudy liquid to a
clear gel. Continue stirring until it
is completely clear and starts to bubble.

Adding food colouring 4 Take the pan off the heat and use the
to the mix will colour spatula to spread your plastic on a sheet
of aluminium foil. It will take about a day
your plastic to set, but once it has you will have your own
homemade plastic. It is completely biodegradable
and environmentally friendly.

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Butter it up YOU WILL NEED:
Acpthoamemrtsixibectilunemreseidxoitswfutroiwtenhsoe.eoSsarhucmabhksooetrateshnsoecumreb. eSsstcouaampnttceteoermsfeinjidxudtmtuhorbrueoltesu,dwgcthhaoalgalteenidtto’hstcehomrellbrao.udiCdtesrne,ooahft!macvheiesmmoinicneaultolyef
Thick cream
Clean jar or food container with a lid
Sticky tape
Bowl

15 mins

1 Take the cream out of the fridge 2 Start shaking the jar. Nothing
and leave it for 30 minutes, so seems to happen at irst, but
it reaches room temperature. soon you’ll feel something
Half-ill a jar with the cream. Put more solid in the jar. Keep going
the lid on and tape it down so that until you can see a solid lump.
it can’t come off by accident.

colloids Shop-bought butter Buttermilk Butter 3 Take the lid off the
Your homemade butter probably jar and pour out the
SCIENCE AROUND US doesn’t look or taste like the contents into a bowl.
shop-bought variety. Salt, colouring, The cream has turned into
lavouring, and preservatives are a creamy blob of butter
often added to commercial butter in a pool of milky liquid.
to make it look and taste better,
and to keep it fresh for longer.
Gas or vegetable oil may also be
whipped into the mixture to make
it spread more easily.

TOP TIP

wcapownuntitttbtayhuiaoinnttYdguthedoereraur,ba-c(nucmvprotaeeitatnnraekycamrsihncgtp.ogloleeUafeptassasdrnsesoa)ujtaclmatepe.rpa.bstlaIrhsefbsetbyltteoyeicurin,

how does Cream While churning Butter
this work?
The fat blobs The fat contains tiny
CtiauaSthinssrstopetyufrimeaataadcmtccelrlidyaotmoeilrnpsraodcetldapeahqtteiloesunesmptisebroseemoimfcscstufatihiaficiallcsstcrnskiodouatestibnyrosmcepsspgoteuueewpalsrtsoniihscelifclfieedwescedr,esotra.ofiplontilAnoeacrwnrmirradaepaeitmancatemetgarieotrxul.iblutcelsSsuutldteirhatfiietsnaabee.tnkalrroe.T’insneoBeldgammummyhttuoethuaoellrselkelrssdiecoiicoasutnrahfnelatneetsealhssm.remaoYamatotramohuewugcalarhsoeskiioltleelhons.eidr., Tiny blobs of fat are join together drops of water
suspended in water

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Holding it YOU WILL NEED:
together
Four clean jars with lids
Ssfrtooirmmtheleiqlmiquuitdiodsgsleik–tehsetuhrc,isthh, aeysoyusooihloaanvnesdetwpoaaartdaedtrea–andgeaominnu.oTltsoiufmiseuraak–lelyaamssuitbxasbwtlaeenlmlc. eiIxf ttyuhorauet Labels
can hold the mixture together. One egg yolk
One teaspoon flour
One teaspoon mustard
One teaspoon washing-up liquid

10 mins

1 Put equal parts of oil and Colloids in nature SCIENCE AROUND US
water into four glass jars. Any type of substance spread throughout
Screw the lids on, give another produces a colloid. Fog, mist, and
each of the jars a shake, then smoke are all colloids as they contain microscopic
let them sit for a minute. The particles of liquids or solids dispersed through a
oil and the water separate. gas (air). Gases can also be suspended in a solid.

2Take the egg yolk, Pumice is produced when a volcano hurls out
lour, mustard, and frothy lava, which solidiies to make rock with
washing-up liquid, carbon dioxide bubbles trapped inside.
and add each to a separate
jar. Label the jars and give
them another shake.

3 Let the jars sit for a minute.
The contents of the jars with egg
yolk, mustard, and washing-up
liquid added to them stay mixed, but the
jar with added lour separates into layers.

Egg yolk turns The oil, water, Mustard has produced Extra washing-up
the oil and water and flour have an emulsion from the liquid sinks to the
into an emulsion separated into layers oil and water bottom of the jar

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Cyccleentrifuge YOU WILL NEED:
Sssucpbieesentdtaisnintcsaesmstoahmcehyeitncimeoncetasalilneh.daOavneceewtnoatryifsuteogpeda.orAatlthteeisrnimsaittxoivtuesrlpyei,nsgtehintetoomn iyxthotueurrebvaiaktreiho!iugsh
Bicycle
1 In a jug, mix three parts oil with Two small clear plastic bottles with tops
one part vinegar and a little Sticky tape
mustard. Pour the mixture into Jug
the bottles and screw on the tops. Vinegar
Seal the bottle tops with tape so Mustard
that they can’t come undone. Oil
Separating mixtures
2 Shake both the bottles for 20 mins
SCIENCE AROUND US at least 10 seconds so that
the mixture is cloudy and the 3 Turn your bicycle upside
contents have mixed together. One down so it is resting on the
bottle will go in the cycle centrifuge, seat and handlebars. Tape
the other will act as a control. one of the bottles to a spoke on
the back wheel. Positioning the
4 Spin the pedals of the bike bottle with its base against the rim
as fast as you can for about will make it less likely to leak.
30 seconds. Wait for the wheel to
stop spinning completely so you don’t The one you
get your ingers caught in the spokes. sp un will have
Remove the bottle from the wheel and separated into
compare it with the control bottle. layers

TOP TIP The control
bottle still
Try uthnseeicneegednxatplrosveiefnarupgirmgaeieerretabynotetneo.fftWoohsruheeuti?bcctshhytecoaylennceess looks cloudy
in

Spinning blood
Blood is a mixture of different
substances, which have different
uses in medicine. To separate blood
into its parts, a centrifuge is used.
Blood donations can be spun around
at high speed so that the red blood
cells are pushed to the bottom, with
a thin layer of white blood cells and
watery plasma on top.

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True YOU WILL NEED:
Colours
Water-soluble marker pens in
Chromatography is another technique for separating mixtures. three different colours
It involves passing a mixture through another substance. The Blotting paper or coffee filter paper
different particles of the mixture travel at different speeds Scissors
through the substance and separate out. Water
Three glasses
Paper clips

20 mins

1 Cut three strips of blotting paper or how does Gas chromatography SCIENCE AROUND US
ilter paper to the same height as your this work? A liquid mixture can also be separated
glasses. Use a different colour marker by turning it into a gas. A sample of
to draw a large dot about 2 cm (0.8 in) Mscsfisspiailimzimatexnerrvtaaptsubeitllclireaeeotelsneornsutsdoss–cwnaeewopeardpneesayatit.ssgparoIashiuonnisttnsfeseaphgs,pbeaceataidrephgntrnieaagdtctortelmreaterihtftsihtuipexnhegoatsgeuefrebmtr,mdieodch.itifiltxeOtfefhfoetasenrurmvoreerfeieruneoonosgrtmcffhietsthhasee the mixture is heated to a very high
from the bottom of each strip. mpsmsoapiixarxrttektiuucasrrldeeethsomwr.uoIoitnturhagepsihtaf.otpthTrhecehereyecpfutdharlarilpfyovfeemetrhrleaaatntnhnotdrgolcircguoaahglporthrehuiretyrh,sienwtkhwaseteetr temperature inside a machine and
paper at different speeds. then pushed through a special solid
2 Pour 1 cm (0.4 in) of or liquid column. Each gas passes
water into three glasses. through the column at a different speed
Lower each of the strips and is detected as it reaches the end.
of paper into a glass and ix
them to the side of the glass
with a paper clip. The dots
should be about 1 cm (0.4 in)
above the level of the water.

3 The ink in marker pens is
made up of lots of different
coloured inks. After a few
minutes, each of the dots will
have separated out into different
colours. You will be able to see
which colours make up each ink.

The separation
of the ink is called a
chromatography pattern

Blue Green
Black
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oxidation YOU WILL NEED:
station
Wire wool
Wtirhrhiesevneisrssukibbnlsoetwa–nntcheaessy boarnelcayhkgeoampoiacnraetlowrreajayo.cinRtiuotosngt.ienMtghoiessrtatnochifreoremrmviecnrasel iwbrleesaurcebtaisoctnatsinocnae.rse, Vinegar
Glass jar
Thermometer
Cardboard
Scissors

20 mins

chemical reactions1 Cut out a circle of card that is bigger 2 Remove the thermometer The temperature
than the neck of your jar. Make a hole and card lid. Put a ball of wire rises as the
SCIENCE AROUND USin the centre for the thermometer. wool into the jar and pour rea ction gives
Place the card on the jar and push the vinegar over it. Let it sit for a minute. off heat
thermometer inside. After a few minutes, Remove the wire wool, shake it dry,
take a reading from the thermometer. and pour away the vinegar. The
vinegar strips away the wire wool’s
how does protective coating, exposing the
this work? metal underneath to the air.

ApmdaEoeuecniattirnfnsoxfoooeorfeeruortmenwmneeirratcrtgaghseasallctlceyyenhyinoanc.tsrtadiirmiasmWsonenscnonrpuniahtjecoxochboeleianlsyihreeeusnnceegadtdncetfaaecnosedeadcmnnhglrdl,wetlcmeteeoiiamooertmid,ltotogesnoohemniace.cfbmnconautWaohrothsxekl.lxeeemeh,yaiTbiansnrdgsekehot.gdoneweenStoto.nnhsoiidtrotttTheeehghislmnihewiseegbacaeetrtwhroahrhmhmeretnmneieee.roicdmefrcaTeo,aolascexhliwtrirlecrtchelombieiscoauo(eateodeulholcnktebxbdlelwticesniioio,rrdnooseumdnenavinmeszcdnndoio,netcopsedsslmfsvnroa,,rbr)egceettefutteasooohyaaaontimrmcennjcwidmosftitoisspinaeiiroinro..ornogteenmionWTngnunl.iemhtgniihlatasitatdhssetsarahsenegkok.neideerifns,rdin 3 Put the wire wool back
in the jar. Place the card lid
on top with the thermometer
pushed into the middle of the
wire wool. After 20 minutes,
the wire wool will have gone
rusty. Check the temperature
in the glass. Has it risen?

Fire!
Burning, also called combustion,
is another example of an
irreversible reaction. When
something burns, it combines
with oxygen. Like rusting,
burning is an oxidation reaction.
Burning is a much faster and
more energetic chemical reaction
than rusting, so it gives out a lot
more heat – and light, too.

32

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Rotten YOU WILL NEED:
apple
One fresh apple
Ifcfeoyemodupoloenuatnvhdeesafarnunaidtpacpnaledrbfboorrenlaodkniogitxedidnoeow.uTnghhini,stitoiswoaitlhlnseitrrarserutvbteosrtdsaiebnclceaeyrse.,Masciuctcriohon-ao.sYrgnoaiutnrocisgamenn’st Knife
un-rot an apple – but you can slow the rotting down. Four disposable plastic cups
Table salt
Epsom salts
Baking soda
Spoon

1 week

1 Number the cups from 1 to 4. 123 4
Cut the apple into four equal
segments and put a segment
into each cup.

Preserving food SCIENCE AROUND US

Various methods are used for

preserving food. Refrigerators chill

21 2 3 4 Cover the irst three pieces of apple it. Freezers freeze it. Food is also
with a different substance. Put preserved by being canned, smoked,
table salt into cup 1, epsom salts salted, dried, and pickled. All of these

into cup 2, and baking soda into cup 3. methods either stop or slow the

Don’t add anything to cup 4; it will be activity of the micro-organisms

your control cup. Store the cups in a cool that make food rot.

dark place where they will not be

disturbed for about a week.

Salt preserves 3 After a week, compare the four
the apple by segments. The control segment has
removing all of probably gone mouldy. The segment
the moisture from cup 1 is probably the best preserved,
as salt draws the moisture out of food and
so the micro-organisms that cause decay
cannot thrive.

Some mould
appears on the
Salt control piece

Frozen peas

Pickled tomatoes

Epsom salts Baking soda Canned fish
appear to
speed up Baking soda
the decay discolours
the apple

Epsom salts Control

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WorldMags.net

Eletpohoatnhtp’asste YOU WILL NEED:
Ccthehoayleemndmp’rtehosawgiennelav-tniettwhspfo.eoeIuyrnrlodsatxphuiedrisseeeeaedcxtpuoptripoeocdrnaleiumcatchoeneensihmttsatfipchotepaeaeelmcrtneah?tat! ahcWlatyietsoltnll,oiswtohykitaeshtao’slsiukttw,egahensetdortemiandegcdtauhitnsiangelgyditsuattspon
Empty plastic bottle
120 ml (4 fl oz) hydrogen peroxide,
no greater than 3–6% concentration
Washing-up liquid
Food colouring
Dry yeast
Hot water
Funnel
Baking tray or shallow pan

5 mins

1 Stand the bottle in the WARNING!
middle of the tray. Using
the funnel, pour the flociqcroYuotnaihondcviucaesyeinsloeanthuxrHbtaoparrlynsuaeteddeiltrodfirliorffnmooba;nsgamoecseosetn.nhkfNptm.3hpewaD–aaevneo6rsreamao%krnrdxshaoiug.adactloretinueegdtsisgossle.eluedOhitsotnihagleiybht.leer
hydrogen peroxide into the
bottle and add a few drops
of food colouring and
washing-up liquid.

3 Using the funnelCatalysts 4 The liquid starts bubbling
again, pour the yeast before producing a foam that
mixture into theSCIENCE AROUND US spurts out of the bottle’s neck.
bottle. Quickly remove the It looks like a massive amount of
funnel and stand back. toothpaste squeezing out of a tube.

2 Mix a teaspoon of yeast The foam
with two tablespoons of is warm, but
hot (but not boiling) safe to touch
water in a bowl.

Rocket fuel
Concentrated hydrogen peroxide,
or high test peroxide (HTP), reacts
extremely violently when a catalyst
is added to it. It is used in jet packs
to propel humans through the air for
short distances. The catalyst in this
case is silver. When HTP lows over
the silver, it produces oxygen and
steam at more than 700°C (1,290°F).
This gives the rocket pack an
upward thrust when it is expelled
through a nozzle at its base.

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Catalytic converters
Car engines produce a variety of gases when they burn fuel. Some of these,
such as carbon monoxide and nitrogen oxides, are harmful to humans

and the environment. To counteract this, cars are itted with catalytic
converters to speed up the decay of these gases. Catalytic converters

have a mesh coated with metals, such as platinum, rhodium, and
palladium, that act as catalysts. When exhaust gases from the

engine pass through, the mesh breaks the nitrogen oxides into
nitrogen and oxygen, which are safe gases, and makes the carbon

monoxide combine with oxygen, producing carbon dioxide.
Foam erupts

SCIENCE AROUND US

how does
this work?

IeiiywfTwtasbrvseelhmieieestataeohcfnhposctwaotoetuttul,uuionhexnoaast.ydnetnlnegblBgeoy.wdeedtyfTehbanctfhnauihrsoospeeodpheamariud.irmsonykeigHindnegas.hdgygau-ntS,douscocotaerpwtehhfomxscdeneltgoiphaeqmehiittlennhuinoyatitceiswdtflodpyharrtiamseeohlwttlttoryegieiraonc–eerpctxwtaeny(ohirihsdaocreapeotetdaalneieaexsounglrftryotncdt-oebgcp–eixdcenoekritoaocdnxsihttmodyehselaoagmueebnwnrpeclgedibftrinni.oleonsolewogcttssthaen)tleeetsesarm
with the dissolved yeast.

Hydrogen peroxide Oxygen Water
makes contact
with the yeast

Hydrogen
peroxide

Yeast

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turn pink YOU WILL NEED:
Water
Maathcnaeidndyydinacisrlheseeommmlvoiiexcneasjdluosimwcaeiert,ehtmeaaasicttthieederssriaooalurscr.ibd.SaSsostomerorsen.bgTachshaeeecsymid. asiWcraaeenlascdkacblahleacadsindeigsnse,dcliiccakoaneltobtohuurersrn.wcsihtkreiicnn Jug
Glass
Distilled water
Phenolphthalein indicator
Washing powder
Vinegar

5 mins

acids and bases 1 Put half a glass of distilled 2 Ask an adult to add about 10 drops WARNING!
water into the jug. Drop of phenolphthalein to the jug of
a teaspoon of washing water. If your phenolphthalein ienxchpaahaerlpaneerurddifmmru,cwlofePhuwernhalasthesiafrweeinnigfndotaalalotlupocloovwshneuweitlnecimhsneglh,aleda-eglt.ve,shsoBeskiegnyoen.gostcpeliuoealaesrlsnuptr,seftebaokidocenrinnimada,.rlilIetsythaiis,s
powder into a glass. is in powder form, only use a pinch.
The water stays colourless. how does
Water is neutral this work?
so the indicator 3 Pour the water from the jug into
stays colourless the glass. When it hits the glass, the AccTsocTscawchcanthphtharrohalrheeoaplealoelraleonreocgmnbdngmtgudiseghodgeorheiodeettaedrryhebirrreslspedktpeiaoihathaandrchafoerlyildearyisistansqdtipiuad.uiccni.ucruescBrblaoPoleiemnaiedstadnhsxocdststiyeiauirhiiimsedsonislnnmnes..n,giaaocoABwswscdtleinophot,iaeahdrbsnathwnusthiiaottcseacecthahshfhdrsteat,aboeueoinnmsclprparexiaseassrrbdiyaeooomnleaglotcaiedldshvsaoeinfpddsuueeinnustrcocchohdrnc.iletaeenedvythhTsnclieduenaerowhdadpcraetmfmeboaeosghthyitbxinhoesscayeyycael,sidatrdwetlihgy,tilvrcarvihaaoetooesurehetngennlhwelleyegyesiorua.sen.wmt,er
water changes from colourless to a or hydroxyl present.
vibrant pink. Phenolphthalein turns pink in
the presence of a base and bright orange
when mixed with an acid.

The liquid turns TOP TIP
pink, which means
the washing powder oI(aftsthcsoyuoeiocdtruhhtahoeaanaudsbdttd,rvibitngiaanethuseufteregtnprwawsainrlidciklozlrlriecmonalapgeirnxsmttcahuooegerfnlaealeii,jnqnaut.uhciaciehdcei)d
is a base

36

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WorldMags.net

Cabbage YOU WILL NEED:
indicator
Red cabbage
You can make your own indicator just by boiling some Chopping board
red cabbage. Use it to test substances around your Knife
house and find out whether they are acids or bases. Saucepan
Distilled water
2 Heat some distilled water in a pan Sieve
and add the chopped cabbage. Large jar
Cook for about 10 minutes, or Four small glasses
until the water goes purple. Turn the Substances for testing, such as lemon
heat off and let it cool. juice, vinegar, baking soda, and soap

30 mins

1 Ask an adult to chop about Distilled
half of the red cabbage vinegar
head into small pieces.

3 Strain the
cabbage water
into a large jar
to remove the
cabbage pieces.
Divide the water
evenly into the
four glasses.

Flower power SCIENCE AROUND US 4 Add one testing
The hydrangea shrub produces different substance to each
coloured lowers depending on the acidity glass. Those that turn
of the soil. It produces blue lowers on the cabbage water red –
acid soils, pink or purple lowers on basic such as lemon juice and
soils, and it has creamy white blooms vinegar – are weak acids.
on neutral soils. Baking soda and soap turn
the water blue because they
are weak bases.

The liquid turns
pinky red because
the vinegar is a cidic

37

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WorldMags.net

Violevnotlcano YOU WILL NEED:

WTrndeherhaaeietcmyhnteiaaaortrcnieciad,csaseialdwasidipncaedytconbsioaa“rlsenlyenebswduasmtsirtiahecul.eispztoRetme”whaeeeitcyaahtcrdioehdcnaehoscdetthmlfwiekoiiercathambtleeshaacisnactdhhucascoateotnhlotaehburreeer.. Empty plastic bottle
Baking soda
Washing-up liquid
Warm water
Red food colouring
Vinegar
Tray
Sand

20 mins

Neutralization 1 Pour warm water into the 2 Add ive drops of
bottle until it is about three- red food colouring
SCIENCE AROUND US quarters full. Add two heaped and then a big drop
tablespoons of baking soda. of washing-up liquid.
Cover the top and shake so that
the baking soda fully dissolves. TOP TIP

Earthly explosion plavsIitfnicaeitsg’fsuathntroenionevtldoo. iTlfctfahaickenueobltiotettrootuluegpt,etasuts.stehseoaon
Real volcanoes erupt because of a
physical process, not a chemical 3 Pile damp sand around
reaction as in this experiment. Molten the bottle in a cone
(liquid) rock called magma forces its shape, but leave the
way up from deep underground and mouth of the bottle exposed.
ills a chamber beneath the volcano. Take care not to let any
The pressure builds up until the surface sand fall into the bottle.
rock cracks open and the molten rock,
known as lava once it reaches the
surface, bursts out.

Foam lava slides
down the sides

of the volcano

38

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WorldMags.net

Steady stream of how does
vinegar is poured this work?
into the neck of
the bottle Wpabscactcrohiacahoceedlireadldtbeinirwuucdobimmcaanoacesnmncadahaaiarciediobntcesdexogaiati,diaan-nldatuttidaeceepabn.lbna(yadClaaidcsqbaakiseuwdrria.enbbi.dalTagtoaHt)khstensoaoseero.wldyodmdrVieenoroaiaevangxwkaecceidwencrotg,,etniafitttnohtthrmhoataeecoaiimpnxyocwnesrn.aaoseatrsldabwwtoweuionadricantsyieahcuiscnimdd

4 Pour vinegar into the Carbonic acid
bottle until your volcano
starts erupting. If it
stops, pour in more vinegar.

Water Carbon dioxide

SCIENCE IN SECONDS

Baking soda bag bomb
You can use the reaction of vinegar and baking soda to create
a bang. Fold two tablespoons of baking soda tightly inside a
paper towel. Pour half a cup of vinegar and a quarter of a cup
of warm water into a sealable plastic bag. Hold the towel parcel
inside the bag, above the liquid, while you seal the bag closed.
Put the bag down and stand well back.
When the liquid soaks
through the paper
towel the bomb
will go off!

TOP TIP 39

bItmnafhokyueitocnabuhgmorlsaivoloivonudaglnca)ttarswonyhfoaouftudsoelioardn.emgAaswldpsndoraooirntidmngpucermcroreedo(adburs.eucete

WorldMags.net

WorldMags.net

copper YOU WILL NEED:
plating
Small jar
Iptdnhouicsslleitgtriovrteaesyintoiccrsoknoleolouguntarieo,tbnimvusee,ttcspahullaabttrsoigntaetghn.teAcheespsumrrotfuwcarecintsehsinocctfooaapllinpeooedntrshetel–uerrc.pntIasrrroottnphicleanlemtasinilpsgwinauitkrshe.easa Vinegar
Salt
About 10 tarnished copper coins
Ungalvanized iron nails

1 hour

electroplating 1 Half-ill a jar with vinegar 2 Take the coins out of TOP TIP
and stir in a teaspoon of salt. the vinegar. Rinse them
Drop about 10 copper coins in water and dry them. Sdou(wscmrtioonoearugpktmneimtnghdegaaitswlnasveuloaitnfxnhabpaiczeaeiletsnrsudiomuartinrrnheeeagenitg.lrtsoTamf. lhruvoeisasmetnawilz)iell d
into the solution and leave them They should now be all shiny.
for 30 minutes. The darker the Drop some nails into the
coins, the better. The dark vinegar and check them
coating is a layer of copper after another 30 minutes.
oxide, formed when copper
reacts with oxygen in the air.

how does The copper on
this work? the nails will
darken over
Tsoiaoohxrneleyusgatv,ietiolntenrneaa,igvoctainthnersegda.ctnWthoodephtsephnaneealrtiylnosowatxuiriliitdpahaedntahddenexaseicsntgitocsairpktoapitvnsoeenrpictaoo,hixslga,iiditrtvighevineeecg.icorTiooathnptaeinppcpgeroooropsdifopifutniectvshreeecsaconcpoadooptiisnnpniesetgi.grv.Iaeinotiintvrhoseen time, just like
the coins did

Negative Positive Positive Positive copper
oxygen ions copper ions iron ions ions are attracted
to the nail

Ippnmtnrooeaitsgsghyiiah,tetiitltvveibvseeaaeevsakeisilnilunuvagmglesprtishahniouoeiyudrnesmasiliollovaanioewnnsrndd, lsnfason.iycaerTemelghtraeaisontnoripgvdloyueaestslisulhioltuomiinnvlwp,eyinth.flhaiuuaelrumksmieoislsinvnuseailup.rtmThsthhiudeieloepbnf,hosowiidtlahtepotictrfmroohadrcoymutofcstutehhsee The nails 3 The nails that were
were originally silver-coloured when
silver-coloured they went into the
vinegar solution will now
have a bright layer of
copper on them.

40

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WorldMags.net

Spruce up YOU WILL NEED:
silver
A tarnished silver item
Silver becomes dull because it reacts with sulphur in the air to Heatproof dish
feolermctroscilhveemr icsaullprehaidcet,ionatobtlaracnksfetarrtnhisehs.ulYphoiudectaonaluumseiniuamn Aluminium foil
foil, leaving the silver shiny and bright again. Boiling water
Two tablespoons salt
Two tablespoons baking soda

1 hour

1 Cover a large heatproof dish 2 Ask an adult to pour in some boiling water, And the award goes to... SCIENCE AROUND US
with aluminium foil – shiny then add the salt and baking soda and Plating is used to prevent corrosion,
side up – making sure to get stir until they dissolve. Place the silver to give objects a hardwearing surface,
it into all the corners. item into the water so it is completely covered. or to decorate objects with a more
attractive metal. The famous Academy
Award, or Oscar, awarded to actors
and ilmmakers is plated. The irst
Oscars were made of gold-plated
bronze. Today they are cast from
a dull grey metal called britannium,
but sparkle once they are electroplated
with a layer of 24-carat gold.

3 Leave the silver object in
the solution for about an
hour. When you come
back, carefully lift your item out
of the dish and dry it. It should
have a new sparkle and sheen.

© A.M.P.A.S.® 41

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WorldMags.net

42

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WorldMags.net

2 ForcemsoatniodnToacwhrnaiepdnnguecssmvahsenaeprkmdyinetabhoskyirntesrgfoowvinrneicnghietgicsst,ol.tdergFrsuooecmprttchuooeerrvsrese.sBta,oarynpeaudnbwndefdhlcyebaa.rytushstcaeoonltnddhtietrnhoygellaifnoUrgerncpifveoueslrlrcewsedees

43

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WorldMags.net

Dome, dome YOU WILL NEED:
sweet
Four eggs
Savsoreucmrphypeeotshrstianhanaadspnudedrospfmrraiaesrgisenilgaemr,aebumeucotshuptnhestectriioraoflnslwygheasetprigreohtnhte.gan.naEbgolegtshsheterhslel,smbaurteot Tape
Pen
Sharp scissors
Bricks or heavy books

20 mins

1 Carefully tap the pointy end of TOP TIP
an egg on a hard surface to
break the shell. The rest of the mthaeDkoeeng’sgtaoswtma–asesyttosyecuortcmahameenclbeuoltesntdeete!etnhgtegsmsooftro
egg must be unbroken. Pour out
the contents of the egg.

Strong shapes SCIENCE AROUND US 2Stick clear tape around
the middle of the egg.
Draw a line at the widest
point and ask an adult to score
it with the scissors.

3Carefully break off pieces
of shell from the pointy end
to the line, then use the scissors
to carefully snip around the line. If the
shell beyond the line cracks, you’ll
have to start again. Prepare three
more eggs in this way.

Solid semicircles how does
Certain shapes are often used this work?
in architecture for their strength.
Many strong structures, like roof Asiidwdsnpnooelraimmeaikgacreeehcdisrhtascs.ihlissTetsaehh.bpsreeYaiteeorwld,aosuoewnnrowicghgfhenihmabcdwtlehvatbacenhdyradyadiusttseahtsirgrteeficobgbhisrutsectesthraeeseesrsnsohlalg.stafrhrAtptaahehenrdeeolgoeofbemavmtrdedhiiecnnekilys’ Arch shape
supports and cranes, use triangular along the curve of the eggshell.
shapes. Arches are useful for Dome works like
constructing bridges as they can a set of arches
support weight above open spaces.
The ancient Romans were expert
builders and often used domes
and arches in their designs. The
Pont du Gard aqueduct (above) in
the south of France was built in the
irst century. It has 64 arches on three
levels. Each level transfers its weight
to the level below and into the ground.

Dome shape

44

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WorldMags.net
SCIENCE IN SECONDS

Strong shapes WARNING!
Using drinking straws and sticky tape,
make a triangle and a square. See how iensxbuapTedcnehtdrdrwaeiemcdenekoeelgynnang,tnsosandohtdeecdgsalatilinsvrargernbaydrrtweehowaaeulyiktekwaltevlbheelbyilirsegaytshco!kts
much force you need to crush them.
The triangle is stronger. Any force you
use to latten a corner also acts along
the straws – it can’t be crushed without
bending the straws or pulling them
apart. The square, on the other hand,
can easily be lattened.

Carefully lay
the bricks
on top of
ea ch other

4Lay out your four
eggs in a rectangle
shape. Carefully lay
a brick or heavy book on
top of the shells. How
many can you add before
the eggshells crack?

The eggs 45
must all be the
same height or WorldMags.net

they will not
spread the

weight evenly

B B B(JJ'RPHV LQGG

WorldMags.net

lbaoutntclhearocket YOU WILL NEED:

Ilpctarautiannnkcclaeihpuslaenscrotohhmceakeyebotdofiotnttthl-eoeNrsboeprcwaikgcteheott.neiH’nssotytwsohceuirivrdeenglrata,iwrsbdtyseounifns. mitnhgoettihowenosr-ladymotoeu Empty plastic bottle
Card
Sticky tape
A cork
Foot pump with a needle adaptor
Water

1 hour

1Push the needle adaptor 2Cut out four ins and a cone from the
through the cork. If the card. Turn the bottle upside down and
adaptor won’t go all the tape the ins to the neck end. Your
way through, cut off some rocket should stand on its ins with enough
of the cork until it does. room underneath to attach the pump.

laws of motion 3Quarter-ill the bottle with water and
push the cork in. It must it very
EUREKA MOMENTS tightly or the bottle won’t launch.
If the seal isn’t airtight, wrap some tape
around the cork then push it back inside.

Laws of motion 4 Go outside and connect
English scientist Sir Isaac Newton the foot pump’s air line to the
(1642–1727) is most famous for his needle adapter. Stand your
theory of gravity, but he also worked rocket on its ins and attach
out three laws of motion that describe the nose cone to the top.
the way that all objects move. The irst
law says that an object will stay still or
move along at a steady pace unless a
force acts on it. The second law says
that when a force acts on an object,
it makes the object change speed or
move in a different direction. The third
law says that when a force acts on an
object, the object will push back in the
opposite direction with equal force.

46

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WorldMags.net SCIENCE AROUND US

We have liftoff
Space rockets work in a similar way to your
bottle rocket. Instead of squirting water out of
one end, they burn fuel to make a jet of hot
gas. The force of the gas escaping from the
rocket in one direction pushes the rocket in
the opposite direction.

5Place the pump as far
from the bottle as you can.
Start pumping air into the
bottle. After a few seconds,
you should have liftoff!

how does
this work?

WARNING! As you pump air into
the bottle, the pressure
ssittvua,ceperatrTevreyrehrdvisniesiuspdiediifusooxdimnthupe.spatenTeiprolnhyeipmugemestedsonrsinooidnoltcniegnkk’st.ecwehaeotniptugyohplootdrahueodib’snavuegceolthff builds up inside.
Eventually, the force of
the air pushing on the
water is enough to push
the cork out of the bottle.
The water rushes out of
the bottle in one direction
and the bottle pushes
back in the other, which
results in the bottle being
launched skyward.

As you pump, pressure
builds inside bottle

Water pushes out,
launching the rocket

47

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WorldMags.net

Gravity-defying YOU WILL NEED:
Water
Plastic bucket
WTtohhfheewecnoaebtanejnetrrcoyetobowujefacctnhattenmscptoiuorvtcetliresta.tivonTehtalhiisncefiartocerslscetter, a(iaitisgnischdatrhelllioenapdelley,cfbceuuonlltyntarssiptftaoeanrtycatldelyrfyiocsrhacpateunt.lhgliWneingigsthaitdmatiroeebwcuttiacmirokdeens)t.. Rope or strong string
Water

10 mins

Circular MOtion 1 Take about 1 m (3 ft) of rope or
very strong string and tie it to
SCIENCE AROUND US the handle of a light plastic
bucket. It needs to be secured very
tightly so ask an adult to help you
tie an extra-strong knot.

2 Add some water to WARNING!
the bucket. Don’t
ill it more than a ttdawhhanDiehnmdoegtwaertsehgchgiehsteehnritefeieqxwitbupiteuefeldtcireroiikimfsgeeyhseototnnfcuf’fttaitrdonmhsou’ettanttddts’ittmootergoieraenr!nisgtfy,,
quarter full or it might
become too heavy to lift.

3 Start swinging the bucket from side
to side, in bigger and bigger swings.
When it gets high enough, swing the
bucket all the way around in a circle
around your hand. If the bucket is spinning
quickly enough, the water will not fall out.

how does Force towards centre
this work? pulls object around
in a circle

Fairground rides Tcftaoohhenfrenedctthsefrpoet.erurWicocnlliiegfhrncaegpilsneuct.phyilrlWrioecnoulgbhveiisudlaiewscinnkitcngheoagtebtllhtjetboeheducwectctabehktronueedwtctscrkiiaeptsehrnetduettaspramirlsptohfiieuddoetnerdacdllee,
You can feel the effect of centripetal force if you dmpthouiedwllidwnnl,geaittooeinfrstdthbhoeeeeicnswigrnacpotleeturlfmlaienlodlsroietduoettwhoiaatf.rndTthgsheritashbvmeuitcyekaiesnts.
take a fairground ride that whirls you around in a
circle. You feel as though you are being pushed
away from the centre of the circle, but in reality
you are being pulled towards the centre by
centripetal force.

If the force is removed, the object
carries on in the same direction

48

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WorldMags.net

Puzzling YOU WILL NEED:
Pendulums
Strong string
A weight swinging on the end of a piece of string is a pendulum. Hang Two mugs
two pendulums together from the same piece of string and they start Two chairs
Scissors
behaving very strangely indeed.
10 mins

The string must sag
a little for the

experiment to work

1 Stand two chairs back to back about 3 Hold one of the mugs up at One swinging
1 m (3 ft) apart and tie a piece of string a 90º angle, then let go and pendulum makes
between them. Cut two more pieces of watch it swing. Keep watching. the other
string, each the same length, and tie each The irst mug will slow down and pendulum start
one to the handle of a mug. eventually come to a stop, and the swinging
second mug will start swinging.
2 Tie the other ends of the pieces of
string to the horizontal string, about SCIENCE IN SECONDS
50 cm (20 in) apart and both an
equal distance from the chairs. Adjust the Arrested descent
chairs so that the string sags a little bit. Take a piece of string about 30 cm
(1 ft) shorter than your height. Tie a
how does metal nut to one end and a mug to the
this work? other. Hold a pencil in one hand and lay
the string over it so the mug is close to
When you pull a pendulum up and then let it go, the pencil and the rest of the string is
gravity pulls it downwards so it swings down to its horizontal. Let go of the nut. It will wrap
lowest point. But as it falls it speeds up, and this around the pencil and stop the mug
speed keeps it moving so it swings past its lowest from hitting the loor. The nut on the
point. Gravity keeps pulling on it, slowing it down until string behaves like a pendulum. As the
it stops and swings back again. If two pendulums are mug falls, the string between the pencil
attached to the same piece of string, they pass their and nut shortens so the nut swings
motion back and forth between each other. One faster and wraps itself around the pencil.
pendulum swings, pulling the string it is hanging from
to and fro. This transfers energy to the second
pendulum, which starts swinging itself.

49

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WorldMags.net

Air-resisting YOU WILL NEED:
eggs
Three eggs
ISajfeoiyromoprueeasdroidrsboitzjpaeenscscotoesmm,feaaetnlhledimgnfggoinsritde. finaqglulsicotkuoltythmtehoagrnerooautbnhodeu,rptsu.itlTlehisdeabryegaEosaoordtnhe’fsoxcgr urtahsveisittyiso. Bin bags
Twelve 50-cm (20-in) lengths of string
Ruler
Scissors
Sticky tape

30 mins

1 Cut a bin bag in half and 2Poke a hole in each
lay it out lat. Using a ruler, corner of the squares.
measure three squares: Thread a piece of string
20 x 20 cm (8 x 8 in), through each hole and tie a
30 x 30 cm (12 x 12 in), knot. Cover the knots with
and 40 x 40 cm (16 x 16 in). tape to secure them.
Cut out all three squares.

Gravity how does
this work?
3Tape each square to Try an even bigger
wrTbAsmgpelhiririogsortooehwigrruvseeleitnweadsasaddrhientgsirisdcgtpecaieeorhatannwrtmttbcahhthnleicueeyge.hsrigseAesatuuenditpairrroesdfunr,sauiefsonuacagshtgrnelhhilfssdaaepattgcorssartaeehowroriaaeenaobscmsormlrjhoeetdfa,uawocaitft,rtnohleesyamersinnmttodhhgtdtovroaearaitecvtnyhgoaitigone.,bttugetjmoeehrrbgtceaehtjgthyegrfeoiocgwshurtsaici,tgtiethrthhhteieht.e an egg by its strings. para chute, or
This can be tricky, so experiment with
Igsccactfotereneyoagnnnopovetttuirbrrttieeehtyjpeefooowocrrffof,ste,ggmlgiirtbkrrreioaaaeufavavnvttiiclihttltaaiytyynelin..lngiTAofsgoohfabdgraettkjirhterasofeeacolulcast.rsptnekiGlinydsnoprgaafbdutlhvoeoelcleisblnteopyj’trawetootpdacfionautidtnthstllhlleus–wtpophroitvaciahmenjykute,r,seayobohtvrofeebaeautcjsrsjheoyaccejiiuufapntsgs’nteashetldraetotshonseef, you may want to ask an different shapes.
where the point of support is. adult to help you. What happens if
The toothpick weighs so you p ut small
little that burning some of holes in your
it away hardly alters the para chute?
centre of gravity.
WARNING!
The forks’ centre of
gravity (marked with bsrToohmkiesenpamrcteehtegisisvgsesisten.ysxtAopmtnheiasarryoidmliuuianeglbtvhnloesotl.huvtooetucsldroembaeete
an “X”) is directly below
their point of support 4Starting with the smallest
parachute, drop the eggs
from a height of about
3 m (10 ft). Inspect the eggs
and see if any survived the fall!

50

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