DONAL VAUGHAN

Balloon Kebab

A trick that will suspend belief. Sticking a sharp skewer right through a balloon without it popping. Seems impossible. Not with a bit of science.

List of things

• Balloon

• Oil or washing up liquid

• Metal Skewer

Method

• Half fill a balloon with air.

• Rub oil or washing up liquid on the skewer

• Insert the skewer through the balloon as close to the knot as possible.

• Have the skewer exit the balloon though the exact opposite end (you’ll notice that there is a darker spot. Aim for that.

Science behind it

Balloons are made of a rubber called latex which is really stretchy. The are inside the balloon is bursting to get out and puts pressure on the balloon. Any hole or tear in the balloon and the air inside can burst out and that pops the balloon. The trick here has got to do with where you stick your skewer. Near the not of the balloon, you’ll notice the balloon appears darker in colour. This is because the rubber here is not as stretched as other parts. This means the balloon has a little bit of slack and can withstand the skewer piercing it. There should also be a ‘dot’ of darker balloon on the exact opposite end of the balloon which is also not as stretched. Sticking the skewer ‘through the knot and the dot’ should mean an intact balloon.

The purpose of the oil or washing up liquid is as an air sealer. When you stick the skewer through, you ‘goo’ should seal the two hole and stop the air leaking out.

Extra stuff           

Skewers are sharp and great care should be taken. Also not everyone likes loud noises so be careful not to frighten anyone with a popped balloon.

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Cola Fountain

This is one of the most famous science tricks around. The Coke and Mentos trick. My twist uses salt instead of mentos

List of things

• A bottle of Diet Cola

• Some Coarse Salt (aka Sea Salt or Rock Salt)

• A funnel or small tube

Method

• Stick a bottle of cola in a basin an unscrew cap.

• Pour some salt into a funnel, with a finger blocking the hole so the salt doesn’t fall out the bottom.

• Hold the funnel over the cola and when ready let the salt fall into the cola

• Stand back and watch the fountain.

Science behind it

Soda drinks have Carbon Dioxide gas in it. Its what gives soda drinks its fizziness. The bubbles are the carbon dioxide escaping. Each bubble is like an escape pod. The gas forms a bubble in a microscopic crack in the bottle, the bubble float up to the top and the gas can escape.

The addition of the salt speeds up this process. Under a microscope the salt is really lumpy. The salt allows millions and millions of bubbles form at the same time. And they all try to escape at the same time. And this chaos causes the huge fountain you see.

Extra stuff

Definitely an outdoor trick. A great trick for experimenting.

You can try big bottle, little bottles. Diet drink regular drinks, different sodas. Try coarse salt, table salt, mentos sweet. Try and see what the best combination is.

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Fireproof Stuff

Here a trick which demonstrates one of the aspects of the fire triangle, heat. You will be able to rub thing through a flame without then going on fire. As this trick uses fire. Adult supervision is absolutely essential and safety paramount. No messing allowed.

List of things

• Roll of Tin Foil

• Sheet of Paper

• Candle & Candle Holder

• Lighter

• Balloon

• Adult Supervision

Method

• Light a candle. Place in a candle holder if needs be. Or use a small tea light candle.

• Take the sheet of paper and fold in half (gently, don’t crease it) so that the top two corners meet the bottom two corners. When looking from the side the paper should make a teardrop shape.

• Slide the roll of tinfoil in to paper recess.

• Holding the paper sheet moving it onto the flame so the paper wrapped around the tinfoil is in the flame.

• The paper will blacken but won’t ignite.

• You can also try the trick with a water filled balloon.

• Stretch the end of a balloon over a tap nozzle and fill the balloon with a half cup of water.

• Carefully take the balloon and blow it up. You should now have a blown-up balloon about a third filled with water.

• Hold the balloon over the candle. Again the balloon will blacken but shouldn’t pop.

Science behind it

This trick is all about heat and the properties of fire. Fire needs three things to work. Something to burn, oxygen and heat. Fire needs heat to work and this trick removes heat from the fire. Tinfoil is made of a metal called aluminium and like all metals is a great heat absorber. The metal foil absorbs all the heat from the flame so the paper doesn’t get hot and if it doesn’t get hot, it won’t go on fire. The balloon works the same way. Here water acts as the heat absorber preventing the balloon from getting hot and popping.

Extra stuff

Safety is the most important thing here. Fire is very dangerous, so adults must always be present. Other tips. Make sure the candle is away from anything flammable in case its knocked over. Have a basin of water ready in case you need to dunk paper that goes on fire.

Only paper that is touching the foil can go in the flame. If there is a gap between the paper and tinfoil, the paper may ignite. With the balloon, don’t hold it over the flame for too long. There is only a certain amount of heat the water will absorb before some heat is transferred to the balloon and it will pop, splashing water everywhere.

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Hair Dryer Trick

Since I don’t have as much hair anymore, I’ve needed a use for my old hair dryer. How about floating things in mid air. Seems like a productive use of my time. It is when I’m learning about science.

List of things

• A Hair dryer

• A ping pong ball

• A Balloon

Method

• Plug in the hair dryer in

• Hold the dryer so the nozzle points up and tune it on the lowest setting.

• If the option for having no heat is available, choose this option. Some hair dryers have separate buttons for air flow and heat.

• Place the ping pong ball on balloon into the flow of air and it should get trapped floating in mid air.

• Slowly begin to rotate the dryer so the air flow instead of pointing up points to the side.

• Even at a 45 degree angle you will find the ball or balloon will stay floating in the air.

Science behind it

This is a demonstration of the Bernoulli Effect. Daniel Bernoulli was a Swiss scientist from the 1700’s. The Bernoulli effect shows that as a liquid or gas’ speed increases, its pressure decreases. The fast-flowing air coming out of the hair dryer is moving much faster than the surrounding air so the pressure is much lower. This creates a wall of pressure around the fast-moving air. This invisible wall stops the ball or balloon from flying away. If the object tries to leave the flowing air, the wall pushes it back, so it stays floating in the flowing air coming out of the hair dryer.

Extra stuff

Ask permission before using the hair dryer. Also add 10 or 20 drops of water in the balloon before blowing it up. It may not seem to weigh any different but it do slightly and gives the balloon a little bit more stability.

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Homemade Champagne

List of things

• An Acid such as lemon juice or vinegar

• A base such a baking soda or bicarbonate of soda

• Washing up liquid

• A bottle (preferably with a thin nozzle)

Method

• Add your lemon juice to the bottle.

• Next add your washing up liquid and mix gently

• Finally add your baking soda. As soon as you do this the chemical reaction will start.

• Quickly screw the thin nozzle cap on the bottle (or alternatively just block the mouth of the bottle with your thumb making sure to leave a little gap for the gas to escape)

• The foam should squirt out under high pressure.

Science behind it

This is a simple chemical reaction. Lemon juice and vinegar are classified as weak acids. Baking soda is a weak base (a special base called a carbonate). When you mix an acid and a carbonate together, they start making a gas called Carbon Dioxide or CO2. This gas mixes with the washing up liquid and makes a bubbly foam which needs to escape from the bottle. By only giving it a tiny gap to escape, the pressure builds up and it shoots out of the bottle like a champagne bottle.

Extra stuff

Definitely an outdoor trick. Needless to say don’t aim it at anyone and wear goggles if you can.

Alternately, instead of covering the mouth of the bottle, if you leave it the gassy foam comes out at a much lower pressure and looks like lave coming out of a volcano. You could even add some red food colouring to give it a lave look.

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Ketchup Diver

Here’s a fun bit of telekinesis (the ability to move things using only your mind). It will appear that you are moving a ketchup packet up and down inside a bottle of water without touching it. All you need is magic powers and a little pressure!

List of things

• Empty 2 litre plastic bottle with cap

• Water

• Ketchup Packet (found in pubs and diners)

 Method

• Gently push the ketchup packet into the bottle

• Fill the bottle up with water. Fill to the very, very top. You don’t want any air in the bottle.

• Gently screw the lid on tight.

• The packet floats at the top of the bottle, but when you squeeze the bottle, the packet will sink down to the bottom.

• Let go and the packet will float up to the top again.

• The trick works best if you try to hide the fact that you are squeezing the bottle.

Science behind it

This trick is about pressure. When the ketchup packet is made in the factory, along with the ketchup, a little bit of air is trapped inside. This air bubble is what keeps the packet floating in the water. When you squeeze the bottle, you’re adding pressure and the air bubble gets crushed. Its very hard to crush a solid or a liquid, but gases are easy to crush.

The air bubble is less dense than water, and therefore floats. When you crush the bubble, it becomes denser than water and sinks. (It’s the same amount of air, but in a smaller amount of space).

When you let go of the bottle, the air bubble can stretch out again and is once again able to float the packet up to the top of the bottle.

Extra stuff

Couple of thing to point out:

• Not all packets will work, you need to find floats vertically in the bottle, if the packet if too heavy it will sink, and the trick won’t work.

• The trick may not work straight away. When inserting the packet into the bottle, you break up the air bubble inside, stopping the trick from happening. If you make up your ketchup diver, and then leave it for a day, gravity separated the ketchup and the air bubble, and it make the trick work more easily. I find then after a few days, it’s a lot easier to get the trick to work.

You could experiment with different sized bottles. Maybe a smaller bottle will work with smaller hands. You could try replacing the ketchup packet with other packets you find. Like brown sauce, mayonnaise, vinegar, mustard. Do any of these work to?

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Jeff The Unicorn

This is one of the most fun tricks to do. To do this trick you don’t need a unicorn like I use in my show. You just need a bottle and some household ingredients, and you can create an amazing chemical reaction like a real scientist.

List of things

• Plastic bottle

• Bakers yeast

• Hydrogen peroxide (H2O2) – See extra stuff for safety note on this

• Washing up liquid

• Hot water

• Funnel

• Food dye

• Plastic cup

Method

• Place the yeast in the bottle and add hot water. You want it quite hot but not scalding as it may kill the yeast. The hot water is to wake the yeast up.

• Put about 100 mls of H2O2 in a plastic cup. Remember to use gloves at all times and be very careful with the peroxide. Strictly, only grownups may handle it.

• To the peroxide add some washing up liquid and food colouring and stir. I use a wooden skewer to stir and then I throw it in the bin.

• Using a funnel, pour the peroxide mixture into the bottle with the yeast in it. Throw the cup in the bin.

• The reaction is almost instant. A foam should start forming and will soon expand out of the bottle. The foam is safe to touch, although may get quite warm.

Science behind it

This is proper chemistry happening here. It also shows how chemicals can change after reactions. Yeast is a living organism that we used to make things like bread, cakes and beer. Yeast eats sugar and makes gas. This is what gives cake and bread its spongy texture.

When the yeast meets the H2O2 is eats it and starts ripping of oxygen. The peroxide (H2O2) is turned into H2O and O. H2O is more commonly known as water and O is Oxygen, the air we breathe. This oxygen mixes with the washing up liquid and this is what causes the foamy mess. The foam is quite warm because while the yeast is changing the peroxide it uses energy, and this generates heat. A chemical reaction like this is called an Exothermic reaction.

Extra stuff

Hydrogen Peroxide (H2O2) is the most dangerous chemical used in any of the tricks. It must be handled very carefully and can only be handled by responsible grownups. Always where gloves and make sure it doesn’t contact the eyes or skin. It can be bought in pharmacies or hair salon supply stores. Read the bottle before using it.

After the trick is done, the foam is safe to touch. But the inside of the bottle may still have some unreacted peroxide in it so wash it out carefully.

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Leak-Proof Bag

Here’s a great trick to do on a grown up. Stick pencils through a bag of water without spilling a drop. Add extra excitement buy doing the trick with the bag over their head.

List of things

• A zip lock sandwich bag

• Some water

• Some pencils

• Food colouring (optional)

• A willing volunteer

Method

• Half fill a zip lock bag with water.

• You can add some food colouring to make it more visual

• Check to make sure the bag is not leaking.

• Hold the bag over your volunteer and slowing insert the pencils through the bag.

• Make sure the entry and exit points of the pencil is in the water.

• If done right, none of the water will leak out. 

Science behind it

Its got to do with pressure. You’d expect the water to leak out when you insert the pencils. And normally it would. This is because air would push down on the water and as the water leaks out, air would replace it.

The trick is the bag is sealed. Because of this, air can’t get into the bag. The water can’t leak out if there isn’t anything to replace it. This is why it’s so important that the bag is air tight.

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One-Handed Waiter

This is the trick I performed using only one hand. This is a similar trick to the upside-down water trick. You’ll get a baking tray to stick to the glass using air pressure. But here you’ll use a candle to create and vacuum which will let you lift a heavy baking tray rather than a card coaster.

List of things

• Baking tray

• Tealight candle

• Lighter

• Toilet paper

• A large glass

• Some water

• (Optional – some drinks to go on the tray)

Method

• Place the tray on a flat dry surface.

• Take 3 squares of toilet roll and put them on top of each other in the middle of the tray.

• Add some water (you may need to experiment to find the right amount of water)

• Place the tealight on the wet tissue and place the pint glass upside down over the candle.

• Wait for the candle to go out and wait 10 seconds.

• Lift the glass, if done right, the baking tray will lift with it.

Science behind it

Lots of things happen for this trick to work. When the glass is placed over the candle, it traps a certain amount of air in with it. The candle heats the air. Hot air expands and some of it leaves the glass pushed through the rim of the glass. As the candle is burning, it is using up oxygen, when the oxygen runs out the flame dies. After that the air in the glass cools and shrinks.

As the air shrinks, air from the outside will come in to replace the air that was pushed out initially, but the wet tissue stops that from happening. This creates a mini vacuum. This means there is lower pressure inside the glass than outside and this creates a seal. (See the upside-down water trick to learn more about air pressure).

Extra stuff

This trick took me a long time to get right. I knew it could work but it kept failing. So, I experimented with the size of the glass, the type of tray, the amount of water, what tissue I used. One issue for example is I was using kitchen roll instead of toilet roll. May not seem like it would be any different, but it was. The kitchen roll was too absorbent, and it stopped the water forming a seal.

This is what science is all about. You have an idea and you experiment and see what happens.

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Potato Gun

This is a trick where you can make a rocket launcher, or a potato launcher at least. And at the same time demonstrating some science.

List of things

• A piece of PVC pipe used in household plumbing (the white plastic pipes)

• A potato

• A knife (for grown-ups only)

• A long stick (like a broom handle)

• 10 paper cups (or something else to use as a target)

Method

• Have a grown up cut a potato in half vertically and lay both halves of potato flat on a strong surface (I always try to use the ground rather than a table)

• Using your pipe (I use one that’s cut about 2 feet long) like a cookie cutter, cut a piece of potato out of one half. If done right, you’ll have a potato plug stuck in one end of the pipe.

• Plug the other end of the pipe with the other half of potato.

• Now you ‘ll have a pipe with a potato plug in each end. It’s now ready to launch.

• Using your stick and aiming at your target, shove the stick up one end so that you push one plug of potato up to the other plug.

• With a loud pop the plug at the far end will pop out and hit you target, hopefully.

• You ma need to practice a few times before you can aim it properly.

Science behind it

This is a demonstration of Boyle’s Law. Robert Boyle was an Irish scientist from 1600’s. One of his famous discoveries was Boyle’s Law (showing pressure and volume being inversely proportional. Simply put, as volume goes down, pressure goes up.)

As you push one piece of potato towards the other, the trapped volume of air inside the pipe decreases. As the volume decreases, the pressure increases. Eventually it builds up to the point, the piece of potato at the far end shoots out.

Extra stuff

The stick – You want a stick that’s long enough to push the potato up (at least ¾ of the length of the pipe. It also needs to be flat (not too pointy anyway) at one end because you want to push the potato not stab it.

The potato – When you cut the plug out of the potato, I use the rest of the potato for my dinner so I’m not wasting food.

The launch – I find it easier to gently push the potato piece up an inch or two inside the pipe before I launch. Its stops the stick from slipping when I go to shove it.

You can only use the potato plugs once. You may be able to use the plug inside the pipe again if you shove it down to one end but the plug that fires out is no good. The trick works because the potato forms a tight fit inside the pipe allowing the pressure to build up. If you push the piece that fires out back in, it won’t form a tight seal and the pressure won’t build up. And it won’t work as well.

Needless to say, don’t point the launcher at anyone, animals, fragile objects, windows etc. And don’t set up your target on front of these things either.

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Tray Slap

Have you ever seen a trick where a person pulls a tablecloth off a table without breaking any of the plates and glasses? This trick is based on the same science but just on a smaller scale.

List of things

• Plastic tray (I use a small chopping board)

• Glasses (or plastic glasses for safety)

• Small round objects (I use satsumas, you could use balls or even eggs)

• Toilet roll tubes

Method

• You can use one two or three glasses for this trick. Let’s just say you’re using two for the trick.

• Place the 2 glasses a couple inches apart from each other.

• Place the tray on top (make sure the tray is completely flat; no lip on it)

• Put the toilet roll tubes on the tray so they sit directly above each glass.

• Place your round object on each tube. You want it to sit on the tube, not sit inside it.

• Firmly hit the tray from the side so it slides horizontally away.  You need to hit it hard enough that it slides away but not so hard you end up hitting the glasses too.

• The tray should slide away and take the tubes with it. The oranges (or whatever object you used) should fall and land in each glass.

Science behind it about it

There a lot of science here. Its got to do with two forces, friction and inertia. If you need to learn more check the internet but I’ll try an explain using an everyday example. Have you every been standing on a bus and it drives off? When it does you kind of fall backwards. (Which is why it is always important to hold a rail while moving around on a bus). When the bus moves, your feet which are touching the bus move too, but your head and body and in mid air so they stay where they are, and therefore you appear to fall backwards. The same happens with this trick. The tray is like the bus and the tube is like you. When the tray moves it pulls the toilet roll tubes with it. The oranges are in mid air and stay where they are. Once the tray and tubes are gone gravity pulls the oranges down and they fall in to the glasses.

Extra stuff

If you want to be extra brave, you could use eggs instead of oranges. If you are, ¾ fill the glasses with water so when the eggs fall in, the water will protect them from smashing.

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Upside-down Water

This is the first science trick I every learned and showed me how amazing science can be. The trick allows you to hold a glass of water upside down without spill a drop.

List of things

• Glass

• Card coaster

• Water (dyed with food colouring is optional)

Method

• Half fill a glass with water

• Place coaster on top so it completely covers the rim of the glass.

• Holding the coaster securely in place, carefully flip the glass upside down.

• When you remove your hand from the coaster, it should remain in place keeping the water in the glass.

Science behind it

It’s all about air pressure. There is air in the glass and it want to leave. It pushes down on the coaster. This pressure is known as air pressure. There’s also air in the room and it wants to get into the glass so it pushes upon to the coaster. Since there’s more air in the room than in the glass, there is more air pressure pushing up than pushing down so the coaster stays on the glass. Pressure alone doesn’t stick the coaster to the glass. The water plays a big role in two ways. Water is actually quite sticky and helps stick the coaster to the glass. Secondly and more importantly, it keep the outside air and the air in the glass from mixing. This seal is quite strong and even shaking the glass won’t dislodge the coaster

Extra stuff

If you’re feeling extra brave you can attempt this trick over someone’s head. Do they trust science? I recommend using a grown ups head. They won’t mind if they get a bit wet. Will they?