Reminds me of when I was in my early teens. I fooled around with rockets.

The best one I ever made was from a the metal tube out of a ball point pen. It was fat at the top but it reduced down to normal size on the ball end which made a natural nozzle.

I made the fins out of an aluminum toothpaste tube and I plugged the top with a wooden nose cone wrapped in aluminum foil.

I packed it with potassium nitrate and sugar and maybe a trace of sulpher and or charcoal, I can't remember.

That sucker flew straight up about 50 feet, made a 90 degree turn and headed straight for the neighbors picture window. I ran out of fuel just before it hit.

I heaved a huge sigh if relief and never fired any more rockets.

In the process I learned how to make wonderful stink bombs using only sulphur and candle wax. I would set them off in the boys restroom at school and exit the area pronto.

So you see, I are a rocket sientist too.