On Tuesday 14 February 2017, Class 3 constructed and launched rockets made out of 2 litre plastic bottles, cardboard and lots of masking tape. They used water and air as fuel.
The air in the rockets was pressurised using a bicycle pump, and this pressure pushed the water at the bottom of the rocket out at high speed. This created thrust that made the rocket lift off.
We investigated what forces acted on the rockets in the five phases of flight – the pre-launch, primary fuel, secondary fuel, coasting and recovery phases – and learned about thrust, drag, gravity, air pressure and water pressure.
Two experiments were undertaken, using rockets of different designs, to find out whether having nose cones and fins makes a difference to the length of flight, and how much water is required to create the longest flight. Although the first experiment was inconclusive, the second experiment led us to conclude that 500ml of water, one quarter of the volume of the bottle, created the longest flight.
Our rockets are now hanging up in Class 3.