How the Water Rocket Pictures Were Made

Water Rocket Setup

The same concept is used as in the water balloon pictures, except I improved the setup this time. Instead of using an old fashioned movie projector as the source for a light beam, I used an infra-red LED focused through some binoculars creating an invisible beam of infra-red light passing across the table to the sensor on the other side. This way the beam of light wouldn't show up in the picture.

It was rather difficult to focus the beam of infra-red light on the sensor at the other side of the table because we couldn't see it. We had to rely on a meter measuring the strength of the received beam and move the binoculars around until we arrived at the maximum level.

The electronics for this setup were fancier as it allowed for an adjustable delay between the time the beam is broken and the camera flash is triggered.

There were some extra difficulties when taking these shots. First of all since we couldn't see the infra-red beam of light going across the table I wasn't sure exactly where to position the rocket so it would pass through the infra-read beam when launched. Finding the beam took some time, again looking at the meter measuring the strength of the received beam to tell us when the beam was broken.

Another problem was launching the rocket itself. The rocket typically travels upwards about 40 feet in a second with great force. Our garage ceiling is only about 12 feet high, so a rocket catcher device had to be built and attached to the ceiling to catch the rocket after it was launched.