Other easy tricks for birthday party |
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Catch the postcard
Hold a postcard in your left hand, your right hand is ready to catch the postcard,
but the fingers are not touching it, as you see in the picture. If you let the postcard go,
you'll find it easy to catch it with your right hand before it falls down.
Now repeat this easy trick with your friend. Let him hold his fingers on each side of the postcard, as you did before. Let the postcard go. His fingers will not catch it. You can repeat this trick as often as you want. He will not catch the postcard. You can catch the postcard because your brain can send "let it go" and "catch" signals to your two hands at the same moment. But when you hold the postcard for your friend to catch, his brain must first see that the postcard is falling, then send a "catch" signal to his fingers. This takes more time. That is why your friend cannot catch it. |
A lemonade-straw can go through a potato
You don't think this trick is possible, but it is. Hold an unpeeled potato and a straw as shown in the picture.
Your finger must cover the top opening of the straw. Strike the potato quickly with as much
force as you can, but be sure the straw is perpendicular to the potato. After some practice
you will be able to do this easy trick almost every time.
The explanation of this easy trick is this. You are holding the potato in your hand; so it is in a state of rest. It is inert. The straw which strikes the potato has a great impulse of force. The pressure of the compressed air in the straw will keep it hard. That is why it goes through the potato. |
The sugar cube can burn
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A catalyst in chemistry is a thing which helps to cause a chemical reaction,
but it doesn't itself take part in the reaction. You can demonstrate this scientific trick
at birthday party with a sugar cube, some cigarette ash, and matches.
First put the sugar cube on a plate and see if you can make it burn with the help of a match. You will find it impossible to do that. Now rub some ash on one side of the cube and try again. This time it catches fire and burns well. The explanation of this easy trick is this. There is some lithium in the ash. Lithium is a very light metal. This lithium is the catalyst. It helps to make the sugar burn, though the ash itself cannot burn. |
