Create a Puff Rocket

This is the kind of thing I wish I had back in grade school. I could have launched these across the room without anyone being the wiser. Be sure to fold the nose down securely, or you’ll have air leaks (and no launch!)

A rocket has a few parts different from an airplane. One of the main differences is the absence of wings. Rockets utilize fins, which help steer the rocket, while airplanes use wings to generate lift. Rocket fins are more like the rudder of an airplane than the wings.

Another difference is the how rockets get their speed. Airplanes generate thrust from a rotating blade, whereas rockets get their movement by squeezing down a high-energy gaseous flow and squeezing it out a tiny exit hole.

If you’ve ever used a garden hose, you already know how to make the water stream out faster by placing your thumb over the end of the hose. You’re decreasing the amount of area the water has to exit the hose, but there’s still the same amount of water flowing out, so the water compensates by increasing its velocity. This is the secret to getting the air in your bottle to make the rocket fly the farthest. When you stomp of the bottle, you push the air through a small exit hole (the straw) at a higher velocity.

When you do this experiment, think about which kind of bottles will work the best. And does straw length matter? In our testing, we had one rocket that cleared 25 feet!