St. Peter's Primary Bray Blog

Hi, I’m Dillon Ebbs and I’m in 6th Class. Every year, St. Peter’s BNS participates in the BT Young Scientist Competition. Most people don’t know this, but the BT Young Scientist has a primary section called the ‘Primary Science Fair’. We have entered this for many years and our projects have been about many things including a study on lifeboats, the physics of the Funfair and how chocolate is made.

This year’s project was called ‘The Science behind Illusions’ and Ms. Sexton’s 6^th Class spent a long time working on it to prepare for the exhibition.

We went to the exhibition in the RDS on  Saturday, 12^th January. It was so exciting to see all of the projects and meet other young people.

The judge said our project was very exciting and that our explanations were very good. He also said he liked our descriptions and how we spoke to the public when they came to visit our stand.

This picture shows the five boys who represented our class with our teacher, Ms Sexton, and the judge who presented us with our prize. We prepared our project by carrying out a number of experiments and writing up our findings. The following pages describe how we prepared the project and also what we discovered along the way. We divided our experiments under three categories – senses; light, heat, water and air pressure; and motion, inertia and gravity.

Senses

The Phantom Coin

The phantom coin works because the nerve endings in your head feel the coin and don’t feel it when you take it away. You demonstrate the trick first and then tell your volunteer to try get the coin off their forehead without touching it. It worked really well on me because I thought the coin was still there. – Jamie

A hole in the hand

You roll up paper and look through it, then open both eyes and put your hand beside it. It looks like there is a hole in your hand. Light enters both your eyes and these signals are translated in your brain into the things you see. Because the image from each eye is slightly different, your brain makes sense of it for you. In this case, it looks as though there’s a hole in your hand. I tried it with a ruler and it and it worked. – Adam

Floating Arms

Pull at your pockets with both hands for as long and as hard as you can. When you let go, your hands will float up by themselves. This trick works because some muscles are tensing and when you let go, they relax. Luke

Imaginary Ball

Your partner pushes against your hands as hard as they can. You push out at the same time. When they let go, it feels like you have an imaginary ball. This works because your muscles tense and relax, like in Floating Arms. Pearse and I showed the class – Blaise

Winding Fingers

This is another partner trick relying on your muscles releasing energy. Jamie showed us this one. Your partner taps your fingers and they seem to close by themselves.

Lee

Magnetising Pencils

You get two pencils and push them together as hard as you can. When you pull them apart, they seem to be drawn together as if there is a magnet in them. This is another trick that uses your muscles, but the only difference is that it relies on objects rather than parts of the body. I tried it with Jake as a partner trick and we held one pencil each and it still worked. This was my favourite illusion. –
Ryan

Multiplying Marbles

You ask your volunteer to cross their middle and index fingers. You ask them to close their eyes and ask them to guess how many marbles are in your hand. It confuses the nerve endings and makes you think that there are more marbles there than there actually are. Jake

These are our booklets. We used these to write up the experiments and to help us to explain the experiments at the Primary Science Fair. We included information on how they worked and we drew pictures to help explain.

Chris

LIGHT, HEAT, WATER AND AIR PRESSURE

Super cool water

Put a bottle of sparkling water in the freezer and leave it there for a few hours. Take it out and open the lid. The water will instantly freeze. Fizzy water contains carbon dioxide and a little bit of salt. This means that it freezes at lower temperature. When the lid is opened, the carbon dioxide is expelled, causing the water to freeze – Jamie

The Gorilla Effect

This was not our best trick.  You rub your finger on the soap and scatter the pepper over the bowl of water. Put your finger in the water and watch all the black pepper rush to the other end of the bowl. We could not find black pepper so we used nutmeg. It did not work perfectly but it worked a bit. The soap upsets the water molecules causing the pepper to move away – Tautvydas

Potato Skewer

You have to try get the straw through the potato. Some of us worked it out by ourselves. If you cover the top of the straw, it traps the air molecules and gives the straw extra strength. If you do not cover the straw it will not work – Pearse

So Long Suckers

Pour the water onto a plate and put coins in a pile. Light two or three matches at once and lay them down, still burning, on top of the pile of coins. Quickly put the glass over the matches. As the matches burn, the water gets sucked up into the glass. The heat of the flame increases the water pressure in the glass, forcing air out. The flame goes out when all the oxygen is used up and the water is sucked into the glass. We tried it first and you could not see it clearly so we added some food colouring.  It was really impressive.

 This was the most popular illusion – we repeated it for every class in the school but we had to warn them not to try it at home. We were not allowed to light matches in the RDS so we made a little video to explain how it worked. We did the same with the ‘Fire Extinguisher illusion.

Fire Extinguisher

Light the candles. Pour the vinegar into the jug and add the bicarbonate of soda. It starts to fizz and then when you hold it over the candles, the candles go out. This is because the mixture reduces the oxygen in the air around the candles. The candles need oxygen to burn, reducing the oxygen will cause the candle to go out.

Jake

Bending Light

Fill a bottle with water. Punch a hole in the bottle about a quarter up from the bottom. Shine a light through the bottle opposite the hole. The light seems to bend because the light travels along the path of least resistance and as the light is reflected off the water – Blaise

MOTION, INERTIA AND GRAVITY

Cola Can-Can

Fill the can with 100ml of water and tilt it on its side at a 45degree angle. It will balance by itself. This is just a simple trick of physics. I knew how to do this one already so I showed everyone. It does not have to be exactly 100ml so I usually do it with a third of the can – Lee

Wood-snapping paper

Put the ruler on the table with about 40 % of it over the edge. Place the newspaper on the table covering the ruler. Crash your hand down on the ruler. It will break in half. This trick works because of air pressure. The sheet of newspaper on top of the ruler is being pushed down by air, holding the ruler on the table, allowing the force to break the ruler. This actually worked when we hit the ruler cleanly – Nathan

Coin snatching

Put a coin flat on your elbow. Bring your elbow down sharply, your hand will follow and the coin will hang in the air long enough for your to grab it. This is because the coin, thanks to inertia, resists gravity for long enough for you to catch it. We were very good at this trick – Tautvydas

Frustrating papers

Tear a piece of paper in almost three parts and try to pull it apart so all three parts separate. It is impossible until you use tape to attach 50c to the top of B. Attaching the coin increases the inertia enough to cause the paper to break in both spots. This was a tough one to get. Only a few people managed it  – Ryan

Living on the edge

Interlock the prongs of the fork. Balance the central point between the two forks using a toothpick. Balance the toothpick on the edge of the glass and then let go. This is all about the centre of gravity. Our Learning Support teacher helped us with this – Junior

Pool hustling scam

This involved placing a nail in the middle of three pool balls. Depending on how you set it up, you should be able to knock over the nail, but when you set it up slightly differently, your partner will not. This trick was all about momentum. We found it difficult to make work – Luke

Tablecloth trick

Hold the edges of the tablecloth really tightly, Pull the cloth away and everything should stay on the table. This is inertia as well. We found this really hard to manage but we decided that if you had a more slippery tablecloth, it might work better – Blaise

Magic Straw

Pick up a straw, wrap it in your jumper and with a sharp motion pull the straw through it. Then place it on the bottle, put your hands near the straw and it will start to move away from your hands. The static electricity and the difference in the charge between the straw and the hand makes the straw move – Cian

OPTICAL ILLUSIONS

As part of our study into illusions, we also considered how optical illusions can trick our brain into thinking that we are seeing something different. We researched different types of illusions and then made a few of our own. This is our 3D hand. We drew around our hands using pencil and then drew straight lines using different colour markers, curving the line when it came to our pencil marks. This example belongs to Adam.

Anamorphic Art

Anamorphic Art needs perspective to be seen properly. It is most commonly used on football or rugby pitches to highlight the logo of the sponsor. We decided to make our own anamorphic letters by adapting a tutorial we found online. First we drew a grid on a large piece of paper, using our camera as the point of perspective. If you were looking through the viewfinder, it looked like an even grid, but the lines actually sloped outwards. Next we printed an A4 version of the letter we wanted to draw. We drew a grid over that letter and used this as a guide to draw onto the anamorphic grid template. Then we tidied up the lines with rulers and painted inside the lines.

The day of the Primary Science Fair

On the day, five of the boys travelled to the RDS to take part in the Fair. We set up really early and we had lots of experiments out on the table to show people. Lots of people came over to our stand and we were a bit nervous demonstrating and explaining at first but after a bit of practice, we stopped caring! By the time the judge came around to talk to us, we were all happy explaining our project and in the end, we showed him nearly every experiment on the stand. He was really impressed by the project and by how well we explained everything. We also got to go to a special 3D show on space and we got to see all the other stands in there. It was a really good day out.