It is easy to understand that rocket fly by using reaction when it pushes away something to outside. PET bottle water rocket can fly up to the height of the school roof. Students can have a lot of fun.To enlarge the momentum, water is put in the PET bottle and it can fly higher than in the case of only the air in it. It can be examined how to make the big momentum. It is understood to be able to make the fog and the cloud, when the adiabatic expansion happens suddenly.
Water Rocket building step by step
PET bottle (for a carbonated drink), rubber stopper, airpump, pin for the ball, water, celluloid board and packing,tape
It is better to use the PET bottle for a carbonated drink because of the high pressure. If the PET bottle is cut and the launch pad is made, it becomes easy to fly. Put the head corn on the top and wing on the lower part to fly stably.
It hardly flies only by air in the PET bottle. The water is heavier than the air, so the momentum that is pushed away from the bottle becomes big. Therefore, the rocket comes to fly higher. It is possible to examine the law of conservation of momentum by measuring the height which the rocket flies over.
At the moment of launching, water goes away and the reaction pushes up the PET bottle rocket.
Extension
Let’s make the fog in the bottle. At the moment when the rocket was driven, it becomes white in the PET bottle momentarily. It is because the temperature rapidly falls by the adiabatic expansion when an inside gas expands suddenly.
The fog can be made in the PET bottle in the classroom by using this experiment.
2 The small amount of water is put in the PET bottle, and rubber stopper is put. Put some air in the bottle by air pump.
The fog can be made and it becomes white inside the PET bottle after the rubber stopper is pushed away. If the smoke of the match is put inside the bottle before the pumping, it becomes easy to make the fog. It is quite the same mechanism that can make the cloud in the sky. During the pumping, the air temperature goes up.
After the stopper is pushed away, the adiabatic expansion occurs and the air temperature in the bottle is down. The fog is made.
Level: Primary, Elementary, Secondary
Water rockets are easy to make and use materials found in daily life. Children will be thrilled, and their creativity stimulated, watching their hand-made rockets soar skyward to unexpected heights. Water rockets that perform well have good science behind them
The water rocket body to be introduced in this article will be a basic type that can be made using readily available materials; this type achieves a balance between safety and functionality.