Air Cannon | English

Have you ever seen a cannon that throws out air with so much pressure that your hair gets blows away!
Let us make one for ourselves. You will need one conical plastic bin, an old torn football, a marble, a pair of scissors and a string.
You will need to tear open the football, but careful with the rubber bladder inside. We need that intact. That is going to serve as our stretchable membrane. Now cut the bladder like this. look how stretchable it is! Place the marble right in the centre of the membrane and tie it with a string. This will serve as a holder. Now make a circular hole in the middle of the closed narrow end of the bin. Be careful while doing so, you need that whole to be exactly in the centre, not too big and not too small. Now stretch and attach the membrane on top of the open end of the bin like this. Like this. Seal it off with a cello tape.
Your air cannon are now ready.
When you pull the marble, it stretches the expandable membrane increasing the volume inside the bin. Air immediately fills in. Now if we let the marble go, the membrane is going to come back to its original position, decreasing the volume inside the bin and the extra air molecules in the bin are going to get cramped together. This forms a pressure wave and it travels forward as the disturbed air layer passes on its energy to the next layer. As shown in the image.
This pressure wave can knock a glass off the table if the cannon is aimed at it! It is so much fun to blow out a candle with the pressure wave your cannon produced! you can try this at your next birthday party!

Team: Ashok Rupner, Apurva Barve, Shanti Pise, Prachi Pasalkar, Shilpa Jain