Make a Short Range Bottle Rocket

Boom! Load this bottle rocket up and watch it go!

Steps

Get an empty bottle made of plastic.
Make a hole in the cap. Make sure it's not too big or it will reduce thrust and power. It should not be too small either, or there will be an explosion.
Find a way to seal the hole with something removable. For example, tape is good.
Pump air in from a bike pump.
Build a reusable stand, pointing it at an angle.
Put the cap on with the pressure item in the bottle. Make sure the hole in the cap has tape or something removable.
Let the pressure build up inside the bottle, not too long or there will be an explosion and not too short or there will be no thrust.
When the pressure is ideal, remove the tape quickly. The pressure should blast out the hole for acceleration. The rocket's pressure will accelerate it and it will go {{safesubst:#invoke:convert|convert}}.

If you don't feel right doing this, don't.
Try making a longer more powerful rocket by cutting and sealing multiple bottles
Try adding a rudder.
Wear protective clothing.