How can you play “William Tell” with more safety than a bow and arrow? How about a hand-held Air Cannon? Sure, you can buy one for about $15, or you can build one for around $5!
What You Need:
A 5 gallon bucket (you can get these at any hardware store. Cheap is good.
A cheap, plastic shower curtain liner
A bungee cord that is big enough to wrap around the top of your bucket. You can get these usually at the hardware store as well, so just take your bucket over and test them out. You want a nice, tight fit.
A responsible adult to assist
Here’s What To Do:
Have your responsible adult cut a small hole (about 3″ in diameter) in the bottom of the bucket using the box cutter. BE VERY CAREFUL!
Use the scissors to cut a circle of plastic shower curtain liner that about 8″ larger than the diameter of your bucket. For example, my bucket had a 12″ opening, so I cut my circle about 20″ in diameter. Here’s a helpful hint: cut a piece of string the length of the radius (1/2 the diameter) of the circle. Tape a permanent marker to one end and hold the other end of the string onto the plastic shower curtain. Pull the string tight. While holding the end down and the string tight, move the marker around the center to create your giant circle!
Place your plastic circle over the top of your 5 gallon bucket. While holding it tight, place the bungee around the top of the bucket. You’ll probably need your responsible adult to help you, as it can take four hands to do this part. Carefully pull on the edges of the plastic until the show curtain is very tight across the top of the bucket. Be careful – you don’t want it to tear.
Now place a few empty paper cups on a table, aim the hole at them, and tap the plastic – you should get a blast of air that will knock them over!
Air is made of matter, which means it can exert a force. You can feel air on windy days. When you tap on the plastic sheet, you apply a force to the air inside. This force pushes air out the hole in the bottom. Plus, the hole is smaller than the diameter of the bucket, which causes the air to come out with more pressure, much like putting your finger over the end of a garden hose. Have fun!