background image

 WHAT’S HAP

PENING?

HERE'S HOW

1.   Place the bar magnet on the table and 

start by moving the compass very 
slowly around it in a tight circle.

2.   Then continue moving it around the 

compass in larger and larger circles. 
Keep your eye on where the needle is 
pointing as you do this.

Compass needle 
as bloodhound

YOU WILL NEED

→ bar magnet
→ compass

With each rou

nd, the needle 

behaves accor

ding to the sa

me 

principle. It ac

ts as if the ma

gnet 

were surround

ed by lots of li

nes 

coming out of o

ne pole, which 

pass through t

he space arou

nd it 

and then retu

rn back to the

 other 

pole. These lin

es are known a

magnetic line

s of force. 

A magnet, suc

h as the comp

ass 

needle, will al

ways try to or

ient 

itself such tha

t it is aligned w

ith 

these lines of f

orce.

2

1

32

EXPERIMENT 23

Summary of Contents for 665050

Page 1: ...t Germany 49 0 711 2191 0 www kosmos de Thames Kosmos 89 Ship St Providence RI 02903 USA 1 800 587 2872 www thamesandkosmos com Thames Kosmos UK LP 20 Stone Street Cranbrook Kent TN17 3HE UK 01580 713000 www thamesandkosmos co uk EXPERIMENT MANUAL Magnetic Science ...

Page 2: ...tore them near heat sources Do not use electrical outlets for any experiments Never insert wires or other metal pieces into outlets The electrical voltage 110 volts can kill you When experimenting avoid connecting the battery terminals directly to each other the battery could explode Avoid short circuiting the battery or batteries After the experiments always completely disconnect the electrical o...

Page 3: ...bus found his way across the open seas You will find supplemental information on pages 18 19 25 35 36 42 and 43 CHECK IT OUT Magnetic Force and Magnetic Fields Pages 26 to 36 How to make invisible magnetic fields visible with Magnets Pages 44 to 48 665050 02 270217 1 CONTENTS Electromagnetism Pages 37 to 43 Build your own electromagnet ...

Page 4: ...please check all the parts against the list to make sure that nothing is missing If you are missing any parts please contact Thames Kosmos customer service What s in your experiment kit Checklist Find Inspect Check off Any materials not contained in the kit are marked in italic script in the You will need boxes 1 3 4 2 5 6 7 8 10 11 9 KIT CONTENTS Additional things you will need 1 5 volt AA batter...

Page 5: ...ily found near the ancient town of Magnesia in Asia Minor they were called magnets Today magnets play an important role in many everyday and technical devices You may know about magnetic closures on kitchen cupboard doors for example But you ll also find magnets in speakers in bicycle dynamos and in multiple locations in cars Now it s time to learn about the mysterious nature of magnets Magnets Ir...

Page 6: ...gnet and the ball magnet Lots of magnets YOU WILL NEED all of the parts inside this kit 1 2 There are various types of magnets in your experiment kit All of them will have an effect on the box with iron powder the iron bar the plastic chips and the compass So you can use these four items to check whether an object is a magnet even when you can t tell by looking because the magnet is hidden inside ...

Page 7: ...d each other and stick together But the others seem to find each other attractive as well They exert a mysterious pull on each other and you really need to use some force to pull them apart again So magnets exert a mutual attraction on each other Some will even flip around in the process TIP Magnets influence and interfere with each other So you should always place only those magnets on the table ...

Page 8: ...t with the block magnet What s the difference It all depends on the distance YOU WILL NEED horseshoe magnet block magnet iron rod 2 3 1 The force that magnets exert on each other is largely a factor of how far apart they are The closer they are the stronger the magnetic force that you ll feel But as you move them farther apart the force quickly grows weaker With the block magnet you will feel a st...

Page 9: ...arious household items WARNING Make a wide detour around the TV the computer especially diskettes and magnetic media video and music cassettes and credit and debit cards The magnet would destroy the data stored on them 2 You will notice that the magnet only attracts certain objects while others don t seem interested in it at all There s an explanation for that Magnets only exert their force of att...

Page 10: ...lock magnet Iron turns into magnet YOU WILL NEED block magnet iron rod plastic chips At first the iron rod will attract one or more of the chips So the magnet doesn t only attract the iron rod it also makes the rod magnetic so that the rod in turn attracts the iron rings around the plastic chips The chips will drop away from the iron rod however once you ve removed it from the block magnet The rod...

Page 11: ...he magnetized needle in a safe place you ll need it again later A new magnet is born YOU WILL NEED block magnet iron rod compass long sewing needle Without the treatment with the block magnet the compass needle won t react much to either the iron rod or the sewing needle if it does the sewing needle must already have had contact with a magnet With the iron rod still nothing happens after treatment...

Page 12: ...difference now in the distance at which the rod starts to roll toward it Test the other materials as well by sliding them in front of the block magnet Penetrating force YOU WILL NEED block magnet iron rod cardboard paper knife made of steel plastic wrap fabric aluminum foil ruler The magnetic force penetrates almost all the materials without losing much of its strength at all Only the steel knife ...

Page 13: ...magnet and bar magnet as well What do you notice Finding the force YOU WILL NEED horseshoe magnet block magnet bar magnet iron rod 1 2 You will notice that each of the magnets has certain locations where it attracts the iron more powerfully With the horseshoe and bar magnets it s the ends that are the strongest while with the block magnet it s the large surfaces Not all parts of a magnet are unifo...

Page 14: ...th ends of the bar magnet What do you determine 4 Do the same thing with the ball magnets Place them on a smooth surface for your investigation Exploring the poles YOU WILL NEED all the magnets It s strange Sometimes you can feel the expected force of attraction but at other times the two magnets don t seem to want to get together at all something pushes them apart The ball magnets will even flip ...

Page 15: ...one ball with one color and that of the other ball with the other color 3 Let all of the balls click together in turn and make your marks on them Important Whenever you have used one color to mark one ball be sure to use the other color to mark the other ball 4 Use the bar magnet to test the marked locations What do you notice The markings reveal the truth the balls have two poles too No wonder si...

Page 16: ... first one with their two repelling sides facing each other You will notice that it s not so easy to do without making the lower one scoot away 3 When you finally manage to do it quickly let go Jumping magnets YOU WILL NEED 2 ring magnets 1 2 3 The magnet will really jump up into the air 14 EXPERIMENT 11 ...

Page 17: ...What happens now Hovering magnets YOU WILL NEED all the ring magnets ring magnet stand Even the very first ring magnet will hover freely a few centimeters up in the air All of them will end up hovering above one another as if held up by an invisible hand When you push down on the top ring the lower ones will also shift down a little even though there s no direct contact Conversely the lower ones w...

Page 18: ...ink the iron rod would fall Does it fall Magical forces explained YOU WILL NEED all the ring magnets iron rod When you start to insert the iron rod into the hole you will feel a little resistance at first but then the rod will practically get pulled inside The rings hold it so tightly that even its own weight won t pull it out again There s a powerful magnetic force inside the rings that holds the...

Page 19: ...ith the iron rod Disappearing poles YOU WILL NEED bar magnet horseshoe magnet iron rod The horseshoe magnet and the bar magnet became one single magnet when they were stuck together That s why you hardly detected any magnetic force at the place where they met But the two outer poles were still there After the magnets are pulled apart again the previously attached poles regain their former strength...

Page 20: ...d cobalt almost as strongly PERMANENT MAGNETS possess a magnetic force all on their own and they retain it permanently This experiment kit has numerous permanent magnets in different shapes some with plastic coverings These too are produced artificially so they are stronger than natural magnetic rocks PERMANENT MAGNETS possess a magnetic force all on their own and they retain it permanently This e...

Page 21: ...ature after its discoverer the French physicist Pierre Curie Each material has its own unique Curie temperature For pure iron it is 766 degrees Celsius If you heat iron above that point it will no longer be attracted by a magnet although it will regain its magnetism once you let it cool down below that temperature again BAR MAGNETS are composed of a huge number of tiny magnets lined up in such a w...

Page 22: ...e noticed how a compass needle will move and sometimes even dance wildly when a magnet gets close to it The compass needle is a very sensitive indicator of magnetic force Now it s time to investigate the reason for this 20 ...

Page 23: ...l 3 Now move the iron rod which had been lying alongside the block magnet toward the compass Even when the magnet is pretty far away the needle moves and points to it It can even sense relatively weak magnetic forces Thanks to its high mobility it is mounted on a thin support in such a way that it moves very easily it reveals these forces quite clearly It even reacts readily to the iron rod which ...

Page 24: ... turn the magnet around 4 Perform the experiment with the other magnets as well Hold the horseshoe magnet so that first the north pole and then the south pole is closer to the needle The needle points to the pole YOU WILL NEED all the magnets compass The compass needle recognizes which pole is turned toward it If it s the south pole it turns its red end toward the magnet if it s the north pole it ...

Page 25: ... magnet and move it so that first one pole is pointed toward the horseshoe magnet and then the other pole Also try the same thing with the other magnets Magnet on a string YOU WILL NEED all the magnets string scissors While it s hanging from the string the horseshoe magnet responds by turning like a compass needle That shows that the compass needle is also a magnet 1 2 EXPERIMENT 17 Compass 23 ...

Page 26: ...et far away and pay attention to the direction the needle points after a few minutes 4 Where does the needle point when the disk stops moving Compare its position with that of the compass needle The sewing needle shows the direction YOU WILL NEED polystyrene disk bar magnet compass tape magnetic needle from Experiment 6 bowl water The needle always turns to point in the same direction even if you ...

Page 27: ...nly introduced about 600 years ago with far reaching consequences This is what enabled brave European seafarers to venture out onto the open ocean The age of exploration had begun and Christopher Columbus crossed the Atlantic and sailed to America The compass needle is a magnet mounted in a way that lets it move easily Its red end is the north pole as you can see from the fact that it is attracted...

Page 28: ...ake a magnet s force visible since the powder accumulates wherever the magnetic force is strongest What s going on with the pretty iron powder patterns what do their lines of force mean and what do those lines have to do with Earth You will learn about all these things and more in this chapter Magnetic Force and Magnetic Fields 26 ...

Page 29: ...r The different magnets produce different iron powder patterns You can use the iron powder to render the magnetic force visible At the poles which is where the magnetic force is strongest the fine iron filings will even stand erect You can see that particularly clearly with the bar magnet and the horseshoe magnet Since the block magnet has the strongest magnetic force you can even use it to move t...

Page 30: ... little skill to get the two magnets in just the right position 4 Exchange the block magnet for each of the other magnets in turn How close does each of the other magnets have to be for the needle to be in the middle Who is stronger YOU WILL NEED all the magnets compass polystyrene disk ruler The needle has to decide which magnet it s going to point toward The greater the distance from which the t...

Page 31: ... of the ball magnet Hold the ball magnet at the distance that will make the compass needle remain halfway between the two magnets again Continued on the next page Adding and subtracting forces YOU WILL NEED bar magnet 2 ball magnets 2 ring magnets polystyrene disk compass 2 1 Magnetic Force and Magnetic Fields 29 EXPERIMENT 21 ...

Page 32: ...some extent HERE S HOW IT CONTINUES 3 Now hold the ball tight and let the second ball magnet click to the first one so they stick together by magnetic attraction Where does the needle move 4 You will have to move the two balls apart a little before the needle returns to its previous position 5 Now take the two ring magnets What happens when the second ring magnet turns its repelling pole toward th...

Page 33: ...compass needle when you slide the iron rod in front of the horseshoe magnet Muted magnetic force YOU WILL NEED bar magnet horseshoe magnet compass iron rod Apparently the magnet is so fond of the iron rod that less of its magnetic force spreads out from it therefore its effect is weaker So when a piece of iron is attached to the poles of a magnet it appears much weaker from the outside than when i...

Page 34: ...ompass needle as bloodhound YOU WILL NEED bar magnet compass With each round the needle behaves according to the same principle It acts as if the magnet were surrounded by lots of lines coming out of one pole which pass through the space around it and then return back to the other pole These lines are known as magnetic lines of force A magnet such as the compass needle will always try to orient it...

Page 35: ...ible YOU WILL NEED all the magnets box with iron powder In a magnetic field each individual iron particle turns into a tiny magnet that behaves similarly to a compass needle These magnets stick together by their mutually attracting poles and form chains in the magnetic field running parallel to the lines of force These chains are particularly easy to see with the horseshoe magnet running in the sh...

Page 36: ...ystyrene disk simply use another floating base such as a saucer The magnetic force of Earth YOU WILL NEED all the magnets polystyrene disk compass bowl saucer water magnetized needle from Experiment 6 The bar magnet quickly turns so that the end marked with an N is pointing to the north while the other end points to the south The other magnets and of course your magnetized needle as well also orie...

Page 37: ...magnets and all magnetic compasses react to Earth s magnetic field isn t actually produced by a permanent magnet but by enormous electric currents circulating deep beneath the surface in its metallic core MAGNETIC MOUNTAINS C In fact you can t detect any particularly strong magnetic field at Earth s magnetic poles And there s nothing very unusual about the landscape there The supposed magnetic mou...

Page 38: ...near the geographic north pole is logically a magnetic south pole MAGNETIC FIELD The lines depicted here are just a model But you can picture a magnet as producing a countless number of lines arranged tightly together This invisible force of a magnet is known as its magnetic field We can neither see nor feel a magnetic field but iron and other magnets will react to it by being attracted repelled o...

Page 39: ...a compass needle reacts to magnetic fields Will it also react to electricity You can use the wire included in the kit to assemble a small electromagnet with its magnetic force supplied by electric current Then you can test its powers Electro magnetism Electromagnetism 37 ...

Page 40: ...attery contacts Watch the compass needle as you do this CAUTION Only connect the wire to the battery very briefly for just about one second The powerful current will heat up the wire and the battery You could burn yourself with the hot wire and the battery could get damaged by the heat or quickly run out Magnetism from electricity YOU WILL NEED wire compass 1 5 volt battery scissors tape sheet of ...

Page 41: ... the last experiment tap the wire ends against the battery terminals Keep your eye on the needle Electromagnet with intensified effect YOU WILL NEED wire compass horseshoe magnet 1 5 volt battery AA scissors tape sheet of letter size paper The needle really moves this time The more wire you have next to it the more dramatically it jerks to the side The coil with its larger quantity of wire seems t...

Page 42: ...rod into the coil and briefly let the current flow again Intensifying the magnetic force even more YOU WILL NEED iron rod wire compass 1 5 volt battery AA tape sheet of letter size paper At first the needle doesn t react particularly strongly after all most of the wire is still pretty far away from it The iron core intensifies the power of the electromagnet quite a bit though Now even with a consi...

Page 43: ... coil now 3 Repeat this experiment but first reverse the battery terminals so the current flows the opposite direction through the wire What are the positions of the needle this time The current flow really does transform the coil into a magnet and this electromagnet has a north and a south pole just like a bar magnet as the compass needle clearly shows And when the current flows the opposite dire...

Page 44: ...eviously thought of these two things as being completely different were highly surprised But there had already been a few clues before then People had often noticed that a compass needle could become reversed after lightning struck a ship Today we know that the lightning s powerful magnetic field reversed its magnetization Gigantic electromagnet at the nuclear research center in Geneva Switzerland...

Page 45: ...lectric current Historic mirror galvanometer ELECTROMAGNETS C have lots of technical and industrial uses namely wherever particularly powerful magnets are needed Recyclers for example use electromagnets attached to cranes to lift heavy pieces of iron To let them go all they need to do is turn off the current Electromagnets are also used in speakers electric motors and power plant generators One of...

Page 46: ...es A little patience speed or skill may be needed Fishing with magnets is a classic game played for decades by children in many parts of the world It s most fun if you play the games together with a friend so you can teach them everything you know about magnets with Magnets 44 ...

Page 47: ...f course it will be easy but sooner or later the balls will start sensing one another s magnetic force with a growing risk that they might clack together The winner of the round is the last one to have set a ball into a hole without making it clack together with the ball in the center That player can assign himself or herself the point total written next to the corresponding hole After about ten r...

Page 48: ...urns each player lowers the magnet into the box without looking into it of course and fishes out one or more chips The winner is the one who catches the most chips Or you could use the permanent marker to write different point totals on each of the chips and the angler with the highest point total wins Magnetic fishing YOU WILL NEED bar magnet or horseshoe magnet plastic chips tape string wooden c...

Page 49: ...Variations a Along with a few friends see who can navigate the race track the fastest Deduct points for errors b You can increase the level of difficulty by increasing the distance between cardboard and magnet for example by using a thick book That will make it harder to keep the ball from rolling off in its own direction Invisible attraction YOU WILL NEED block magnet ball magnet large sheet of p...

Page 50: ...etic axle stick two pairs of ring magnets together and arrange the pairs with their mutually repelling poles facing each other Insert the iron rod through their center holes Now pull the pairs away from each other until they are at the ends of the rod 4 Now you can use the block magnet again to move your wheeled axle Who can make it go the fastest Magnetic snake and magnetic axle YOU WILL NEED all...

Page 51: ...tepZone p 7 Klammern Pr gra p 7 Münzen Xuejun Li p 7 Flasche Daniel Bursch p 9 Mark FGD p 20 top NatUlrich p 24 Irochka p 25 top middle p 37 mid dle right Titelio p 25 top left mattei p 25 bottom middle terex p 26 top p 36 Freesurf p 30 p 33 Justin Paget p 32 Alina Isako vich p 37 top James Steidl p 37 bottom right Frank Wohlfeil p 43 left Bernard BAILLY p 43 middle right oragore p 43 bottom Genti...

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