It’s always the simplest ideas that work mightily. All it took was a bicycle pump, some corks, a needle (the kind for inflating balls), and a 2 liter bottle. Mix that with a bunch of kids orphaned by AIDS, and you get a day full of fun.

I was very lucky to get this shot.

Part of the fun is getting soaked

When the water bottle rocket landed on a roof, the kids climbed up and turned it into a launch site.

Making a very basic water bottle rocket is simple. You can find instructions easily online, but some of the setups are complicated and require kits. Here is what we did.

Supplies: bicycle pump, a cork (that fits a 2 liter bottle), a needle for inflating balls, an empty 2 liter bottle

1. Drill a very tiny hole in the cork

2. Push the inflating needle through the hole

3. Fill the 2 liter bottle about 20 percent with water

4. Put the cork in it

5. Attach the bicycle pump to the inflating needle

6. One person hold the bottle gently (pointing in a safe direction!!)

7. Another person pump air into the bottle until it blasts off

The pressure builds up inside the bottle until the cork is ejected. As you can see, the pressure is high enough to essentially vaporize the water. The bottle goes up at a very high rate of speed. Once the water comes out it’s very lightweight, so it quickly loses speed about 60-80 feet in the air.

There are many options you can add:

- making a simple launcher out of a large can or another bottle
- adding fins and a nose cone so the rocket will fly straighter and higher
- add a parachute and more

With a kit or some engineering know how you can attach a high pressure tip, design a SAFER launch pad (essential when you ramp up in power), and launch rockets very high in the air. Google “water bottle rocket” for more.