the disappearing coin! - · pdf fileyou place a coin on the table right in front of your...

EFFECT:

You place a coin on the table right infront of your friends. Then, while theycontinue to stare right at it, the coindisappears from sight!

DESCRIPTION:

You take any standard coin and place itunder a clear, empty drinking glass. Thespectators can still see the coin clearlythrough the glass. Then you slowly pournormal water into the glass and as it fillsup, the coin vanishes! The amazedaudience can still see through the waterand glass to where the coin used to bebefore it disappeared.

HOW IT WORKS:

When light passes through differentsubstances it can be bent around. This isbecause light travels at slightly differentspeeds in different substances. The coinunder the glass will actually look a bitdistorted because the light is refractedslightly when it goes from the air to theglass (and then from the glass to the airagain). However, your audience is usedto this because they see glass doing thisall the time. Water does the same thing,which is why objects can look likethey’re bending as they enter into water.

The speed that light goes in water isdifferent to air (which is called the

water’s “refractive index”) and at thewater-to-glass boundary the changein speed is so great that the lightfrom the coin gets so refracted itactually looks like it bounced backoff the glass and stays in the water.This is called “total internal

refraction” and means that none of thelight from the coin escapes from thesides of the glass. The coin is there, butlight from it can’t get out of the glass!

HINTS AND TIPS:

The light from the coin does eventuallyleave the glass. After it is totallyinternally refracted on the water-glassboundary, it then hits the top of thewater and is refracted out of the water-air boundary. So if you look directlydown, into the glass, you will onceagain see the coin. So you need to make sure your spectators are lookingthrough the side of the glass.

For this reason it’s best to use a tall glasswith lots of water and have it as high aspossible.

The Disappearing Coin!

Pub8550_MagicStem_A4_UPDATE1 _B&W_PDFs_v1_Layout 1 12/10/2011 15:10

EFFECT:

You hold a large bike wheel up fromboth ends of its axle. Then you let go ofone end and the wheel continues to besuspended in mid-air even thoughnothing is holding it up!

DESCRIPTION:

You will need a normal bike wheel thathas an axle running through the middle.Around each end of the axle you have aloop of rope to hold it. Get a volunteerto start spinning the wheel for you.Once it has reached a decent speed,lower and remove one of the supportropes: the wheel will continue to remainsuspended in the air as if the rope wasstill there! It will even start to driftaround to show that there is nothingattached to the free end.

HOW IT WORKS:

This only works when the bike wheel isspinning above a certain speed. If youtry the trick with a stationary wheel, itwill just

drop to the ground exactly as expected.Practice doing the trick with a helperuntil you find the speed above whichthe wheel will stay suspended in the air.

The spinning of the wheel causessomething called the “gyroscopiceffect”. This is one of the reasons whyit’s very easy to stay on your bicyclewhen you’re rolling along, but as soonas you come to a halt it’s absolutelyimpossible to stay balanced.

Like moving objects have forwardmomentum, a spinning wheel hasangular momentum as it rotates. For thewheel to tip, this angular momentumhas to change to a new angle. Just as itis difficult to stop a large object that ismoving toward you, it’s hard to changethe angle of a large spinning object. Thiswill keep it suspended in the air until itslows down and drops.

HINTS AND TIPS:

The wheel still needs to be supportedthough. So when you remove onesupport there will now be twice asmuch weight on the other remainingsupport. If you are ready for this, youcan make it look like it’s not taking anyextra effort at all to hold it in the air.

If you cannot get a bike wheel on anaxle, remember that this trick workswith any spinning object. If youattached a string to the base of a toyspinning-top, you can then suspend itsideways in the air.

When the spinning object is suspendedfrom one end it will start to rotateslowly around that support point. This iscalled “precession” and if you’re readyfor it, you can make it look like you’redemonstrating that there is nothingattached to the free end.

Makes sure you practise this trick with ahelper to make sure you can handle thespinning bike wheel. You will also needto have a plan for how to stop thespinning wheel when the trick is over!

SAFETY:

A spinning bike wheel can do a lot ofdamage if you’re not careful. Do not let your fingers go anywhere near the spokes as they could get seriouslyinjured. Always perform this trick with a helper and make sure you havesomeone who is big and strong

enough to controlthe wheel safely.

The Levitating Wheel!


EFFECT:

A volunteer tries to put a piece of paperin half, only to discover that it’s joineditself back into one piece!

DESCRIPTION:

You and a volunteer will both take alarge loop of paper each and a pair ofscissors. Then you will both cut rightaround the middle of the loop toproduce two loops: which is exactlywhat your piece of paper will do. Theirs,however, will still be one continuousloop, only now it will be twice as long!

Then you can get two other people totry with two new loops. One of themwill actually get two loops only they’ll bejoined together and the other will getone bigger loop but now there will be aknot tied in it!

HOW IT WORKS:

These are not normal loops, but ratherthey are twisted loops. The properties oftwisted loops were first investigated bythe mathematician August Möbius in1858, so they are often called MöbiusLoops.

The four loops are:

Zero Twists: This is the normal loopthat you can successfully cut in half.

One Twist: This is the loop you giveyour first volunteer that, when cut inhalf, gives one bigger loop.

Two Twists: This will give two differentloops, but they will be linked together.

Three Twists: This will give one bigloop that will have a knot tied in it.

The act of twisting a loop before joiningit together means that the left side ofone end is connected to the right side ofthe other and vise-versa. This is whycutting it in half gives you one bigloops. Two twists connects the left sideback to the left side but only after it has

been wrapped around theright side. Three twists againconnects the left sides to theright sides, but it’s alsowrapped around itself; thisbecomes the knot when it’scut in half.

HINTS AND TIPS:

If the loops are sufficiently long, then it’sdifficult to spot that there are any twistsin them. You can also experiment withusing fabric or ribbon instead of paperas they can be easier to cut. In fact, ifyou use fabric and have a starting point,then your volunteers can just rip the loopin half with no need for scissors.

Before you try this magic trick, do a test-run with smaller loops of paper so youcan easily see the twists and can clearlysee what is happening when they are cutin half.

For the big magic presentation: makesmall secret marks on the loops, or usedifferent colours, so you can easy spotwhich one has a certain number of twists.

Before you try this magic trick, do a test-run with smaller loops of paper so youcan easily see the twists and can clearlysee what is happening when they are cutin half.

For the big magic presentation: makesmall secret marks on the loops, or usedifferent colours, so you can easy spotwhich one has a certain number of twists.

HISTORY:

The area of mathematics which looks athow shapes are linked and connected iscalled topology. August Möbius was oneof the first mathematicians to developtopology.

Magicians have been usingmathematical shapes in illusions formany years. In the early 1900s thisMöbius loop trick was known as the“Afghan Bands”.

Cut in Half


EFFECT:

A bowl full of water you are carryingvanishes in mid air.

DESCRIPTION:

A bowl sits on a tray carried by yourassistant. You pour a glass of water intothe bowl, cover the bowl with a cloth,and lift it from the tray. You stepforward carefully with the cloth coveredbowl, so as not to spill a drop. Suddenlyyou toss the cloth into the air, and thebowl and the water disappear right infront of your audience’s eyes.

HOW IT WORKS:

This is a classic of stage magic, updatedto use the latest in polymer chemistry.There are two elements to the trick:some secret engineering to make thebowl vanish, and some clever chemistryto take care of the water.

Let’s explore the engineering first. Thebowl is actually permanently attached tothe tray; this can be done simply using adrill and a bolt, or even using some highstrength glue. What this means is thatthe bowl will remain attached to thetray even if the tray is turned on its side.The cloth you use to cover the bowl alsohas some secret engineering built in. Aloop of stiff wire, the same diameter asthe bowl, is attached to the undersideof the cloth. This means that if you holdthis wire loop it will look as if the bowlis there, under the cloth. This is whatmagicians call a ‘form’ – a simple wireshape to make people believe a wholeobject is there, when in fact it’s not.

What these two bits of engineeringallow you to do is show the bowl, coverit with the cloth (ensuring the form is

aligned with the actual rim of the bowlas you ‘arrange’ the cloth) and pretendto lift the bowl off the tray (actually justlifting the form in the cloth), while yourassistant takes away the nowsupposedly empty tray. The way for theassistant to do this is by switching fromthe original two-handed hold on thetray to a single-handed hold, casuallycarrying the tray and bowl at their side,with the back of the tray to theaudience so they don’t see the bowl.We’ve now taken care of the bowl, butwon’t the water spill out when the trayis flipped?

Chemistry gets rid of the water problem.Secured in the bottom of the bowl is adisposable baby nappy (or diaper forany American readers). Modern nappiescontain an amazing chemical: aharmless

superabsorbent polymer called sodiumpolyacrylate, [-CH2-CH(COONa)-]n , also known as ‘wetlock’ or ‘waterlock’.A polymer is a long chain of repeatingmolecules (monomers) and in the caseof sodium polyacrylate, because of thesodium, each of these molecules justloves to bond with water. The crystals of sodium polyacrylate can absorbaround 200 times their mass in water,turning the crystals into a gel. Sodiumpolyacrylate was used by NASA indeveloping suitably absorbent long-term underwear for astronauts in space,so it can easily soak up and hold all thewater you pour in from your glass, evenif the bowl is upside down.

The Vanishing Bowl of Water

page 1


This effect is a lovely way of showinghow ‘magic’ comes from combiningdifferent science and engineering areas.Many of the most important researchprojects being carried out today alsorelies on this sort of interdisciplinaryblending.

HINTS AND TIPS:

It’s best to attach the bowl towards oneedge of the tray, it looks more naturalbut also gives you space to carry thecloth and the glass of water on thesame tray.

The bowl can’t be see-through, or elsethe audience will spot the nappy. If youuse a cheap plastic bowl, make sure itdoesn’t let light through before youattach it.

When selecting a tray, steer clear ofstainless steel. It’s too hard to drillthrough, so use a cheap metal trayinstead.

You can secure the nappy inside thebottom of the bowl by using plasticcable ties to attach it to the bolt.

Make sure the nappy is pressed down as flat as possible in the bowl. Thisincreases the area that catches thewater, and prevents the nappy endspeeking over the sides of the bowl!

Don’t pour the water from too high upor it will splash all over the place.

Make sure you give the sodiumpolyacrylate time to absorb the waterbefore tipping the tray/bowl on its side.Stall for time. For example, make a showof checking that every drop of waterfrom the glass went into the bowl.

Practise the tray/bowl removal movewith your assistant. Make it quick and natural looking.

When you’re ready to move the tray and bowl out of sight, get your assistantto move quickly. Do it while everyone is watching you move forward with thecloth and wire form.

The Vanishing Bowl of Water

page 2


EFFECT:

An object – for example a bottle of popor a human head – is placed in a box.Amazingly, it becomes transparent orsometimes even vanishes!

DESCRIPTION:

Introduce your dematerialisation box.Objects placed within can, like ghosts,be made to fade into or out of reality.You can even control the power of thedematerialisation beam, from normal tovanish, by setting the dials on youramazing magical box appropriately.

HOW IT WORKS:

The basis of this effect is physics. Thetechnique used is commonly known as‘Pepper’s Ghost’. It was originally atheatrical technique, the ‘DircksianPhantasmagoria’, invented by Henry

Dircks, but the chemist graduate JohnHenry Pepper refined it when he workedfor the Royal Polytechnic in London inthe 1800s. While Pepper tried his best toensure that Dircks shared the credit,posterity knows the effect as Pepper’sGhost, and this is how it works.

A sheet of flat glass or Perspex lets lightpass straight through, like a window.But that’s only half the story. A beam oflight striking a sheet of glass does twothings – it’s partially transmittedthrough the window, but it’s alsopartially reflected. This is because therefractive index of air and glass isdifferent. The light we see coming fromthe glass is a mixture of the light comingthrough it from behind, but also anylight that’s being reflected from in frontof it. Now imagine we put a sheet ofglass in front of you,

and tilt it 45 degrees to the right.Through the sheet of glass, you can seea brick wall facing you. Off to the rightis an identical brick wall at a 90 degreeangle to the first one, so that it alsopoints towards the sheet of glass.Physics tells us that for reflection theangle of incidence is equal to the angleof reflection. So if we replaced the glasswith a mirror, you would still see a brickwall – it’s just that the brick wall yousaw would be the one off to the right,reflected in the mirror.

Now, in your imagination replace thatmirror with the sheet of glass again, andpretend we installed big stage lightspointing at each wall. We can use thelighting levels to control when the glassacts like a window and when it acts as amirror. Remember, whenever we look ata sheet of glass, we will actually see acombination of the light that comesthrough it and the light reflected off it.This is where Pepper’s Ghost starts itshaunting.

The Vanishing Head AKA Ghost Drink

page 1


If I turn up the lights illuminating thebrick wall straight ahead of you, youwould see the wall through the glass. IfI then dimmed the lights on the wall infront of you but at the same timeincreased the light on the wall to theside, the total amount of light reachingyour eyes would be the same, but nowthe glass would act as a mirror. Youwould see the wall off to the side. Nowimagine you put a person in front of justone of the walls. In effect by fading thelights between the walls I could fadethat person in or out of existence. That’show Pepper’s Ghost works.

The same physics principles make theVanishing Head work. First, make thebox interior totally black, back and sides.Inside your box you put a sheet of well-cleaned perspex. This perspex is angledat 45 degrees to the front of the box, sowhen someone looks in from the frontthey see through the perspex to the

back of the box, but are also

unknowingly getting a faint reflection ofthe side of the box. You can now letPepper’s Ghost materialise. With youraudience looking in the hole in the frontof the box you place an object at theback of the box – if the box is bigenough you can even get someone topop their head through a hole in thebottom. Now all you need to do iscontrol the lighting. One simple way isto have a hole in the top and a battery-operated torch. First use it to illuminatethe object at the back then tilt it toilluminate the appropriate side. Theobject at the back will vanish. Gettingmore technical, you could set up lightsin the box. Then, as the lightsilluminating the object at the back dim,the lights illuminating the side brighten.The effect is the same – controlling therelative amounts of light transmittedand reflected makes things seeminglyappear or vanish.

This ghostly technique is used in funhouses and amusement parks the worldover, but it’s also the basis for heads-updisplays in aircraft. A suitably angledsheet of perspex reflects the brightlyilluminated display of the cockpitinstrument panel so that they areoverlaid on the world the pilot seesdirectly in front of them.

HINTS AND TIPS:

It’s best to do this in a darkened room,so there are no stray reflections.

If you’re feeling up to it, you can usebold stripes or other patterns instead ofa black background, so long as what isreflected from the side matches upexactly with the pattern at the back ofthe box.

You can also double up: to give moreroom in the box for objects (or a head),use two perspex sheets angled 45degrees to the front hole, eachreflecting a different side of the boxwith the same pattern. If you go thisway a simple, single illumination sourcelike a torch won’t work, you need tohave two lighting systems on either side.That lets you fade the two reflections atthe sides in or out. This way can makeone half of the object vanish and theother part remain!

The Vanishing Head AKA Ghost Drink

page 2


EFFECT:

You have the power to make a ballooninvincible.

DESCRIPTION:

You subject balloons to various forms ofabuse. Despite pins and other sharpobjects being plunged into it, theballoon ignores the laws of nature andremains intact.

HOW IT WORKS:

This is a series of effects that take a wellknown phenomenon, balloon bursting,and applies a range of different forms ofscience and engineering techniques toprevent the pop! Each effect can be usedto demonstrate a particular sciencesubject, but as a whole they show that thesame effect can be created with lots ofdifferent methods. The differentapproaches are detailed below, but first weneed to ask: what makes a balloon burst?

Balloons are made of latex rubber. Thismeans that if we were to look at aballoon really closely we would seebillions of long chains of molecules,called elastic polymers, which stretchout to allow the balloon to inflate. Toexplore this, take a balloon and cover itin a regular grid of small dots. As theballoon inflates, this grid of dots willdistort, showing where the moleculeshad to stretch the most. The roundshape of the balloon means thepolymers are really stretched around themiddle of the balloon and less stretchedat the ends. If a sharp object is pokedinto the areas where the molecules aremost stretched, they can’t stretch anyfurther. So they give way, the air insiderushes out and…pop!

Physics versionIt makes scientific sense to place yoursharp object into the balloon at pointswhere the stress is less, that’s at the endpoints. If you take a long sharp bamboocooking skewer and dip it in vegetableoil to lubricate the sharp end, you canpass it right through a reasonably well-inflated balloon from the knotted end tothe far end. The balloon will bepunctured, so eventually it will deflate,but your skewer will pass though safely.Do practise this first, though!

Chemistry versionMaterials scientists combine physics andchemistry to create amazing newsubstances.

If we can add a material that will holdthe polymer strands together we couldpass a sharp object into the balloon.

This is exactly what you do when yousecretly add a bit of clear adhesive stickytape to the balloon surface for this otherversion of the effect. The tape is fairlyinvisible to the audience, and is madeup of a cellophane film with a layer ofadhesive. The molecules in cellophanedon’t stretch in the same way as latex,so if a hole is made in the cellophanetape it holds together. This, in turn,holds together the balloon surfaceunderneath and allows the needle topass through. Again, the balloon will bepunctured and will eventually deflate, sohide it quick. This also helps keep thattelltale tape from being discovered!

Biology and psychology versionThis comes with a bang and a surprise.In actual fact you have two identicalballoons, one inside the other. Roll upone un-inflated balloon and stick it

The Unburstable Balloon

page 1


inside another, then unroll the innerballoon. When it’s in place align theirends together, then slot a strawbetween the two balloons. Blow intothe balloon as normal, keeping thestraw to one side of your mouth. Mostof the air will go to the inner balloon,but some will go into the outer balloon.When the inner balloon has reached asuitable size, use the straw to inflate theouter balloon just a little bit more. Thenquickly remove the straw and tie bothballoons shut. You now have twoballoons, one inside the other, both wellinflated. If you take a pin you can burstthe outer balloon easily, but it will lookundamaged. Thanks to humanpersistence of vision, where the brainretains a picture of things it’s seen justbefore, the two balloons will look likethe same balloon, with only a satisfyingand convincing pop in between.

Mathematical versionThis balloon penetration effect uses oneof those long thin balloons that look likea sausage. You will also need a paper orcardboard tube that you can secure theballoon within. After you have mostlyinflated this long thin balloon yousqueeze it into your tube. The secret isthat you twist the balloon as you put itinto the tube, holding the bottom partof the balloon and twisting the top as itgoes through. What this means is thatalthough the audience thinks theballoon fills the whole space in the tube,in the middle it’s twisted in a pinch. Youcan then safely put pins, skewers, orwhatever you fancy right through thetube, missing the balloon. You can evenpass the tube round for inspection.When you get it back remove all thesharp stuff, and as you take the balloonback out of the tube, untwist. You can

then pass everything round

again for more inspection. There’s nofunny business to be found! Maths hasmade the impossible possible, but yoursecret is hidden in the twisted balloon.

HINTS AND TIPS:

Inflate the balloon fully, then let about athird of the air out, so you can be sureyou haven’t stretched the balloon toomuch.

Make sure your skewer is sharp, anddon’t forget the oil to act as a lubricant.

For the psychology version, you couldput a different coloured balloon inside,and do an amazing colour-changingballoon effect instead.

Don’t forget, take care with sharpobjects and bursting balloons.

The Unburstable Balloon

page 2


EFFECT:

Crushing a plastic drinks bottle from adistance demonstrates the amazingpower of your mind.

DESCRIPTION:

You take an almost empty plastic drinksbottle and pour out the last remainingliquid. Then, while you or a spectatorkeep hold of the bottle, you proceed tocrush it with the power of your mind!

HOW IT WORKS:

The secret is in the water that you pourout initially. It’s warm water, so the airleft in the bottle is much warmer thanthe surrounding air. Put the cap back onthe bottle, and either hold the bottle bythe cap yourself, or give it to a spectatorto hold. As the warm air starts to cool, itwill exert less pressure on the insidesurfaces of the bottle. Normal airpressure outside the bottle will start tosqueeze in on the plastic and crush it.You won’t know when exactly this willhappen; it will depend on relative airtemperatures and the type of bottle youuse, so you need to stall for time,making lots of magic gestures and soon till the crushing commences.

HINTS AND TIPS:

Don’t use boiling water. It will melt thebottle and scald your hands. You justneed warm water, and the Earth’satmosphere will do the rest.

Keep the warm water in the bottle for awhile before you start so the air canheat up.

When pouring the warm water out ofthe bottle, keep the lid on first, turn itover then remove the lid. This way thehot air will stay in the bottle as thewater pours out. Then put the cap backon quickly and perform the effect so thehot air inside doesn’t escape or cool toomuch.

Don’t do this outdoors on a cold day.The hot water will show as steam whenyou pour it out.

Normal air pressure can also crush adrinks can. You really need to heat upthe air inside a lot, so that when it coolsdown there is a lot less pressure inside.Plastic bottles are a safer way to do thesame science.

You can’t be sure when the bottle willstart to crumple, so keep sending wavesof psychic power towards it. When thebottle does start to buckle, make a bigthing of it. You really need to perform tomake this work!

And of course, be careful not to burnyourself with hot water!

The Psychic Bottle crush


EFFECT:

The power of your brain keeps waterinside an upturned glass till you letgravity take its hold.

DESCRIPTION:

You fill a plastic cup with water, place apostcard over it and turn them upsidedown. When you remove your hand, thecard and the water stay in place. Theforce of your will keeps them defyinggravity until a spectator tells you to letgo, at which point the card and thewater instantly fall into the bowl below.

HOW IT WORKS:

This effect works with air pressure, butalso takes a fairly well-known trick andextends it with a magical extra twist.

Take a plastic cup, fill it up halfway withwater, then place a postcard over theentire mouth of the glass. Hold the cardin place and turn the whole thing oversmartly. The air pressure forcing up onthe area of the card is greater than theforce exerted by the water in the cup, sothe card and the water stay in place. Forthose who haven’t seen thisphenomenon before it’s quite magical,and for those who have…well you’ve amind-control twist to add!

The water stays in placethanks to a combinationof air pressure on thecard and the vacuum inthe cup behind it. Theseforces keep the card inplace and prevent thewater from pouring out.To be able to let the cardand the water fall at yourcommand, you need a bitof sneaky engineering. Thecup has a small hole drilledin it. Use your thumb tocover this hole to preventvisible leaks when you fill thecup with water Now gothrough the trick as normal,then when you decide torelinquish your mind control,remove your thumb from thehole. Air can now get into thecup and the vacuum is lost. Thecard and the water will now fallfree as gravity intended.

HINTS AND TIPS:

Do this trick over a bowl or sink toprevent wet floors!

Using a postcard or some other type ofglossy paper is important. Normal paperwill absorb the water, go soggy and fallaway. Messy!

If you want another way to show thepower of air pressure take a ruler, placeit on the side of a table so that abouthalf of it extends off the side and coverthe table end of the ruler with a sheet ofnewspaper. Then hit the ruler. What willhappen? Spookily, the ruler will stay inplace. The force of air pressure pressingdown on the whole area of thenewspaper sheet is more than enoughto balance even a hardy hit on the ruler.

Want another example of how strangethe effects of air pressure can be? Take ashort strip of paper, hold it in front ofyour mouth and blow hard over it,rather then bending down the paperwill bend upwards! The air you blowover will be moving faster, and faster airexerts less pressure. The greater airpressure underneath pushes the paperupwards.

Levitation in a Glass of Water


EFFECT:

A volunteer has two ropes tied aroundthem. When the ropes are pulled tightthey cut right through the volunteer,who then walks away unharmed!

DESCRIPTION:

A volunteer stands on stage while youand an assistant run two ropes behindthem. You then tie the ropes around thevolunteer so you are each holding twoends of either side of them.

When you and your assistant pull themtight simultaneously, they will

seem to go right through the volunteer,and then ropes that were behind themwill now both be in front.

HOW IT WORKS:

When the ropes are passed behind thevolunteer, it looks like both ropes starton one side and end at the other.However, each rope starts on a differentside, goes behind the volunteer andthen comes back out on the same sidewhere they started.

To keep the ropes in this arrangement,you first need to hide a magnet inside

each rope. This can be done byprying the threads of a rope apart,slipping in a strong “rare earth”magnet, and then tightening therope back up.

Then whenyou tie the knotaround thevolunteer,each ropegoesaround thefront of

the volunteer only, but the magnetskeep a bit of the rope held behind them.When you pull the ropes tight, themagnets will separate and the ropesappear to quickly jump in front of thevolunteer.

HINTS AND TIPS:

You need to make sure the ropes areexactly the same colour and length sothe audience cannot tell which end isconnected to which.

If the magnet looks like it might slip out,or causes the rope to be misshapen, itcan be camouflaged by tying that bit ofthe rope in a knot. Several other knotsat equal spaces along the rope will makesure attention is not drawn to themagnetic knot in the middle of therope.

These knots actually make it easier toconnect the magnets together. After youshow the ropes separately to theaudience, you can align them and runthe ropes through your hand matchingup each knot until you get to themiddle. Do this while talking to the

audience or yourvolunteer aboutthe trick withoutlooking at yourhands. Once youhave the twomiddle knotsconnected, walkbehind thevolunteer to givethe other endsto your assistantand this is

The Baffling knot trick AKA Cut in Half by Ropes

page 1


when you can release the now-joinedmiddle knots.

Make absolutely sure that you have onlytied the ropes at the front and that themagnets at the back are not tangled orlooped through each other. You don’twant to hurt your volunteer actuallytightening ropes around them! Have asecret code-word with your assistantthat either of you can use if they noticethe ropes are becoming tangled and youneed to re-start the trick. It’s better tomake some excuses and re-do all of theropes than to perform the trickincorrectly. An audience will neverforgive you if you hurt a volunteer!

Rare earth magnetsRare earth magnets are alloys of rareearth metals such as Neodymium andSamarium-cobalt which form incrediblystrong magnets. Discovered in the1960s they became affordable duringthe 1990s and are used in a high rangeof products such as computer hard-drives, electric motors and speakers.Without rare earth magnets, earbudheadphones wouldn’t be possible!

Danger:Large rare earth magnets are attractedto metal and other magnets sopowerfully they’ve been known to breakpeople’s bones that get in the way.There have even been deaths frompeople who accidentally swallowed rare

earth magnets that have then causetheir internal organs to be stucktogether.

What’s not a knot?Both magicians and mathematicians arefascinated by things that look like knots,but actually aren’t. Magicians use themso something can look like it is securelytied, only for the ‘knot’ to come undonewhen it is pulled. Mathematicians havedeveloped different ways of classifyingknots but are yet to find one way thatcan determine if any tangle of rope isactually knotted or if it isn’t. Knots arean ongoing area of mathematicalresearch.

The Baffling knot trick AKA Cut in Half by Ropes

page 2


EFFECT:

In space a card falls, while a hammerfloats.

DESCRIPTION:

Onboard the International SpaceStation, where everything floats inmicrogravity, a card and a hammer arereleased at the same time, and the cardmagically falls.

HOW IT WORKS:

This is how different magic in spacelooks. Filmed aboard the InternationalSpace Station by Illusioneering teammember Richard Garriott the trick addsa new space-age twist to the classicphysics experiment by medieval Italianscientist Galileo Galilei. Galileo is said tohave dropped a ten-pound weight and aone-pound weight from the leaningtower of Pisa and showed that theyboth hit the ground at the same time.Galileo was experimenting to confirmthat ancient Greek philosopher Aristotle,who said that a ten-pound weightwould fall ten times faster than the one-pound weight, was wrong.

Today we have a useful theory of gravity,through the work of Galileo, Newtonand others, that tells us objects of thesame mass fall under gravity with thesame acceleration. Even if there is verylittle gravity to speak of, for example themicrogravity on the near earth orbitingInternational Space Station, with aboutone tenth of the gravity on Earth, twoobjects of different mass, the card andthe hammer, should behave the same,so with Richard’s recreation there mustbe a trick!

So why does the card fall and thehammer float? The magicians’ code ofsecrecy still applies in near Earth orbit sowe here at Illusioneering aren’t telling;can you can work it out for yourself?Newton says we need a force to makean object move, so if it’s not gravity oreven the lack of gravity that makes thecard fall what could it be? What do youthink?

HINTS AND TIPS:

Take your maths, science andengineering seriously and perhapsone day you too will make it, orhelp others, into space, to floaton a ‘magic carpet’ (that one iseasy, just float) or create the nextamazing magic tricks that work inspace.

FACINATING FACT

Because of a series of local warsthe Leaning Tower of Pisa, the belltower for Pisa cathedral tookaround 170 years to complete. Thetower began to lean even before itwas half built; the foundations sankinto the soil, tipping the building.To make up for this the later stageswere built with a backwards bend totry and compensate for the leaning,the engineers built upper floors withone side taller than the other. Evenwith this heroic medieval attempt tofight the laws of gravity, eventuallythe battle looked like it would belost and the ever increasing tiltwould become tragic, until modernday engineers and mathematicianspredicted that removing soil fromone side of the foundations wouldencourage the tower to tip back

and stabilise itself, and it did! This storyprovides a wonderfully sideward view of the world where amazing modernengineering and mathematical magichelps to preserve marvelous medievalmasonry.

USEFUL WEB LINK

Classroom physics and mathematicalactivities based around the leaningtower are available atwww.upd8.org.uk/activity/304/Leaning-tower.html

The Amazing Falling Card in Space Trick


EFFECT:

You take a container of water and touchthe surface of it. Just by the power ofyour touch, the water freezes solid!

DESCRIPTION:

You start with a tray of water and thengently place a finger on the surface ofthe water. As your friends stare at it, icestarts to expand out from your fingertipuntil the whole block of water is solidice. You don’t even need to touch thewater directly: take a bottle of waterand pour it into a glass. As it pours intothe glass it starts to freeze until there isa frozen block of ice in the glass.

HOW IT WORKS:

The liquid that you’re freezing is notpure water and the resulting ‘ice’ is notactually frozen, it is just crystallised.

Instead of pure water, what you areusing is a solution of water thatcontains sodium acetate (strictly theIUPAC name for this compound issodium ethanoate, but let’s notquibble). Sodium acetate is a salt, muchlike normal table salt except instead ofeach sodium atom being attached to achlorine atom (giving sodium chloride,which is what you have in your kitchen),they are attached to acetate ions (theanion of acetic acid). Sodium acetatelooks like normal salt and tastes just likesalt (do not taste it though!) except withan acidic flavour (due to the reaction ofthe acetate ion with water/moisture toproduce a weak solution of acetic acidi.e. vinegar!) as well. For this reason,sodium acetate is often used asflavouring on salt and vinegar crisps! Ifyou check the ingredients on a savourysnack and see E262 listed, then that’ssodium acetate that you’re eating.

Like salt, you can dissolve lots of sodiumacetate in water but eventually thewater will reach a point where it cannotdissolve any more. However, if you heatthis saturated solution up you can keepdissolving more and more salt into it.Once you’ve heating water up near itsboiling point of 100C and dissolved inas much sodium acetate as you can, youthen let the water cool back downagain. All of the sodium acetate will staydissolved but there is now much morethan would normally be lowtemperatures. This is called a super-saturated solution and the moment yougive the sodium acetate a way to leavethe solution, it will!

Sometimes, just touching the solution –or even bumping it – will cause all thesodium acetate to crystallise back out.To make sure it does this when youwant, you can put a few sodium acetatecrystals on the tip of your finger, or inthe glass, so where the solution contactsthem they start a chain crystallisationreaction.

CHEMICAL INFO:

Sodium acetate can beeasily ordered throughmost chemical supplycompanies. If you talk toa science teacher they willbe able to order itthrough the school’s labtechnician. They’ll alsohave the equipment tosafely heat and super-saturate a solution.

HINTS AND TIPS:

The sodium acetate willcome out of super-saturated solutionreally easily if it contacts anything or isdisturbed. Make sure you only put it in

new and completely clean containers. Ifyou cool the containers, there is lesschance of the sodium acetate comingout of solution. This can be a verydifficult trick to perform because of howeasily the sodium acetate comes out ofsolution.

When the sodium acetate solution‘freezes’ it actually gives off a lot ofheat! A reaction like this that producesthermal heat energy is known as anexothermic reaction. If you later applyheat to the crystallised sodium acetate,it will go back into solution ready torelease that heat again when it re-crystallises. Re-usable heat pads areactually full of sodium acetate for thisvery reason!

Instant Freezing Water Trick

Sodium Acetate:

CH3CO2–Na+

and Sodium Chloride:

Na+ Cl–


EFFECT:

A glass container filled with clear,colourless liquid is briefly covered andsuddenly it has been swapped for a flaskfull of opaque dark-blue liquid! It canthen be changed back without anyonenoticing the swap.

DESCRIPTION:

A conical flask (or beaker) is filled withclear liquids that resemble plain water. Acloth is placed over the flask or a pieceof card is used to block it from theaudience’s sight. When this cloth orcard is removed there will now be adifferent flask filled with an opaquedark-blue liquid. The cloth can bereplaced and removed several moretimes and each time the flask will switchbetween the dark liquid one and theclear water one.

HOW IT WORKS:

The flask itself does not every changebut the liquid inside it is undergoing anoscillating chemical reaction. Part of thetime it is contains elemental iodine andpart of the time the iodine is dissolved inthe solution as ionic iodine. Mixed inwith the solution is an iodine indicator,which is basically starch. In the presenceof elemental iodine the starch turns darkblue. Once the iodine goes into solutionas iconic iodine the starch indicator goesback to being colourless.

You will need to have someone carefullymix the following potion:

10 cm3 1 mol dm-3 sulphuric acid

25 cm3 0.1 mol dm-3 potassium iodide

5 cm3 0.1 mol dm-3 hydrogen peroxide(take care it can irritate the skin!)

10 cm3 0.005 mol dm-3 sodiumthiosulphate

1 cm3 starch solution

In the first, slow reaction, the tri-iodideion is produced .H2O2(aq) + 3 I−(aq) +2 H+ I3− + 2 H2O (I3− reacts withstarch to produce the blue colour)

In the second, fast reaction, tri-iodide isreconverted to iodide by the thiosulfate.I3− (aq) + 2 S2O32−(aq) 3 I−(aq) +S4O62− (aq) (I− is colourless)

HINTS AND TIPS:

After a while the solution will start tochange colour more often as thefrequency of oscillations increases. Thismeans you’ll have less and less time todo the swap until eventually, thesolution will just stay in its dark-bluestate.

If you watch the solution closely, youwill see that it starts to change colourslightly before the actual change. Whenyou see the solution start to go cloudy,you know that the colour change isimminent. Be sure to practice this trickin the lab a few times so you can perfectyour timing before trying it with anaudience.

The Transitioning Beaker Trick


EFFECT:

A bottle containing a disgusting greenliquid becomes different beverages as itpoured from one container to another.

DESCRIPTION:

A conical flask (or beaker) contains agreen liquid. When it is poured into thefirst empty flask the liquid will change toa light red colour; becoming rosé wine.As this light red beverage is poured intothe second empty flask it will switch to ablue colour, becoming blackberry juice.

HOW IT WORKS:

The initial flask contains normal tapwater and universal indicator. Becausetap water is pretty much neutral, theindicator will be in its neutral colour, inour case: green. The first empty flaskactually contains a tiny volume of aconcentrated acidic solution that willturn the solution acidic and so theuniversal indicator becomes red incolour. The final flask has a small volumeof a concentrated basic solution thatwill turn the whole solution basic andso the universal indicator switches tobe blue in the presence of a base.

CHEMICAL INFO:

For the acidic solution we used a smallamount dilute of hydrochloric acid.

For the basic solution in the secondflask, we used a small volume of 10%aqueous ammonia i.e. ammoniumhydroxide (note that this and especiallymore concentrated solutions have apungent smell, so keep your audienceat a distance).

As we poured the acidic solution intothe second beaker containing ammonia,it had to initially neutralise the basebefore the solution could turn basic.Here is the equation of the ammonianeutralising an acid:

NH3 + H2O NH4OH (aqueousammonia)

NH4OH + HCl NH4Cl + H2O(neutralisation)

HINTS AND TIPS:

WARNING: The idea of a mysteriouschanging beverage is a goodstory and helps make this afascinating trick, but neverforget that these are actuallydangerous chemicals. Whileyou may know that whatyou claim to be a deliciousjuice beverage is actually adangerous basic solution,people in your audiencewill not.

Do not leave the solutions unattended,or in the hands of a spectator, in casethey try to drink them!

Dilute hydrochloric acid and aqueousammonia solutions are corrosive sohandle with care and less skilledillusioneer operators should considerwearing gloves.

The Mysterious Changing Beverage Trick


EFFECT:

A flask of solution changes colour whileproducing copious quantities of fog.

DESCRIPTION:

A large conical flask contains a light-green liquid. When some pellets aredropped in, the solution changes to ayellow, or eventually red, colour whileproducing huge amounts of mysteriouswhite fog, like something from anepisode of Doctor Who. This fog willpour out of the flask and drift spookilyacross tables and the floor.

HOW IT WORKS:

The flask contains some universalindicator and tap water (which is prettymuch neutral). The pellets are dry icewhich is carbon dioxide in its solid state.Carbon dioxide will freeze into a solid attemperatures below −78.5 °C and gostraight back into a gaseous state –known as sublimation – when it heatsback up. The water warms the carbon

dioxide up and it is gaseous carbondioxide that fumes out of the beakerlooking like fog because of the watervapour in the air that condenses ontothe cold carbon dioxide fumes. Becausecarbon dioxide is heavier than air and isstill colder than the air in the room, thefog i.e. condensed water vapour willfollow the trail of carbon dioxide fumesand sink down and flow across the floor.

As the gaseous carbon dioxide bubblesup through the water, some of itdissolves into solution. This causes areaction producing carbonic acid,turning the indication yellow andeventually red. This is the same acid thatis produced in carbonated “fizzy” drinkswhich uses dissolved carbon dioxide toproduce the bubbles. This is whysparkling mineral water has a sharp,acidic taste.

CHEMICAL INFO:

CO2 (g) + H2O (l) = CO2 (aq) (most CO2

forms a ‘hydrate’ i.e. CO2(H2O)6)

only a small proportion actually reacts toform carbonic acid (H2CO3 a weak acid)

CO2 (g) + H2O (l) = H2CO3

HINTS AND TIPS:

Dry ice is extremely cold and should be handled with great caution. If itcontacts skin for too long it can causesevere freeze-burns. Always useinsulating gloves when handling dry ice.

The gaseous carbon dioxide that isproduced is heavier than air and willsink to the ground. This is not a problemif you are in a big room, but in a smallenclosed space it could push all of theair out and you will suffocate. Alwaysensure ventilation windows and doorsare open (if possible) have someone elsearound if you are producing a gas thatdisplaces air.

The Smoking Flask (AKA ‘stage smoke’)


the disappearing coin! - · pdf fileyou place a coin on the table right in front of your...

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