What you will need:
- (2) straws: One straw should be slightly smaller than the other so that it will fit inside the larger straw.
- Paper – cut into a 2 inch circle, then folded in half.
- Cellophane tape
- Glue – hot glue gun works the best.
- Adult supervision
- Cut out a two inch circle and fold it in half as shown:
- With the flat edge up as shown, grab the two sides of your ½ circle and twist them down (towards yourself) until the two flat edges meet. Tape the two (straight) edges together to hold this into a cone shape as shown:
- Cut the larger diameter straw so that it is approximately three inches in length.
- Carefully hold your paper nose cone upside down and place a small amount of hot glue inside the tip of the nose cone. Quickly insert the larger diameter 3 inch straw inside the nose cone (in the glue) and hold it straight until glue cools dry. You should end up with a rocket that looks like this:
- Slide your rocket over your smaller diameter straw as shown. Making sure that nobody is in your line of fire, blow as hard as you can into the smaller diameter straw to launch your rocket.
What is going on?
When you blow into the straw you are increasing the air pressure inside both straws, which then forces your rocket to launch through the air. Air molecules take up space. Even though you cannot see the air molecules that are all around us, they do take up space. The air around us actually has about 14.7 lbs of pressure. By blowing more air into the straws, you are increasing the number of air molecules inside the straw, increasing the air pressure. Since there is more pressure inside the straw than outside, the straws are forced apart as the air molecules are trying to escape this high pressure area. This causes your rocket to be launched through the air. By building a nose cone for the front end of your rocket, you are decreasing the drag as the rocket is launched which will allow it to fly farther.
Try adding fins to your rocket and see if that helps it fly straighter and/or farther. You could also attach the smaller straw to the mouth of an empty water bottle using hot glue. Now, instead of blowing into the straw to launch your rocket, you can squeeze the bottle in your hand or use it as a “stomp” rocket as long as you can aim it slightly upward. Be creative. Let us know how it worked and what designs you came up with to make it fly even farther!