Mark the length of the straw on the A5 paper, without the bendy part.
Cut a rectangle that is about 5-cm wide and its length matches the straw you marked in step 1.
Wrap the rectangle of paper tightly around the straw and tape it together to make a tube shape.
Remove the straw from the paper.
On one end of the tube, cut small “teeth” and open them up.
Cut an isosceles triangle (a triangle that has two sides of equal length) and fold it into a cone (How? Just put one side of the triangle on the other). Cut around the triangle’s base to make it as straight as possible.
Tape or glue-stick the cone to the “teeth” on the bottom of the tube.
Cut two right-angled triangles (or whichever shape you’d like your fins to be) and tape them to the body of the tube.
Re-insert the straw into the tube, keeping the short bendy part out of the tube.
Blow into the straw and make your rocket fly!
Changing the design and location of the fins on the tube will affect your rocket’s flying ability. Experiment with different shapes to see how they impact the way your rocket flies. Don’t be afraid to mix it up and experiment with different fins! All you have to do is make new fins from the same materials, then replace the old fins with the new.
What’s the science behind this?
Rockets soar thanks to Isaac Newton's 3rd Law of Motion, which states that every action has an equal and opposite reaction.
In our experiment, we blow air into the rocket. Since one end of our rocket is sealed, the air has nowhere to go, and so it comes back and escapes through the only opening it has - on the other end of the tube. The air rushing out provides a thrust that propels our rocket in the opposite direction. The same principle works on a balloon: when we inflate a balloon and release it, the air rushes out, pushing the balloon in the opposite direction.
So, how do real rockets fly into space? Rocket engines eject hot gas that pushes the rocket up to overcome the gravitational forces that are trying to push it down. The gas is produced through the burning of fuel inside the rocket engine. The gasses shoot backward, pushing the rocket forward even in the absence of oxygen. The greater the rate of combustion, the greater the force (thrust) exerted on the rocket – but this also means that the fuel will burn faster.