As part of 'World Space Week', Year 8 Science pupils investigated how forces enable rockets to take-off. We investigated how the amount of water in a rocket affected the height that it reached and discovered that there is a trade-off between amount of ‘fuel’ (water) and the additional weight that it causes.
Using the foot pump to create the necessary compression, the air pressure builds up until it cannot be contained and the valve is forced from the bottom of the bottle. The air inside then rapidly expands back to normal size shooting the water out at great force. Thanks to Newton’s third law of motion, the bottle is accelerated into the air as it overcomes gravity. The fins help to stabilise it in the air, so it travels in a straight line upwards until the forces of air resistance and gravity overcome the thrust and the empty bottle falls gently back to Earth!
We had some technical problems with launching so the pupils had to consider the design of the rocket launcher and how the pressure was managed in order to identify flaws in the design. We will subsequently compare how the forces acting on the model rocket differ to the forces acting on a real space shuttle so that it can enter space.
DCIS Science Teacher