Water rockets have been a source of entertainment and education for many years. They are usually made with an empty 2-litre PET bottle by adding water and pressurizing it with air for launching. Water rockets are used to help students understand the principle of aeronautics. Aim
The aim was to design and perform an experiment to determine the volume of water to use in order to obtain maximum height for the bottle rocket.
Bottle rockets are often used in science as an experimental apparatus. Researchers use rocketry to understand the principles of Newton’s law of motion. This report will investigate, design, perform and analyse an experiment on water rockets and explain how a water rocket reaches a maximum height using the concept of physics and experimental results. Hypothesis
If the water level in the water rocket is increased, then the chances of obtaining the maximum height will also increase. This is because more thrust (force) is needed to make an object accelerate, and the greater the mass of an object, the greater the thrust it provides.
The group will analyse and determine the amount of water needed to obtain the maximum height of the water rocket. Rocket motors generate a push or “thrust” by expelling a propellant out of the nozzle. The action is the movement of water out of the nozzle while the reaction is the forward motion of the rocket. The greater the “thrust”, the faster the rocket will accelerate. The other force that is acting on the rocket is the gravity; as the rocket goes up with the help of the thrust, the gravity pulls it down and brings the rocket back down to the ground. The group will use water because it is heavier and denser than air. More water molecules are packed into a given volume. Risk Assessment
1. Select a grassy field at least 30m wide.
2. Place the launcher in the centre of the field.
3. Observers should stand back several metres (approximately 10m). 4. The member responsible for pumping air in the rocket should wear eye protection. 5. The bottle rocket should be pumped at the maximum of 40 pressures per square inch (psi) and never above 40psi. 6. When pressurization is complete, everyone should stand back for about 10m for countdown. Two-litre bottles can weaken and explode. 7. Continue countdown and launch the rocket only when recovery range is clear. 8. If you do not experience lift off, call your teacher.
(Remember that the rocket is pressurized and may blast off when you touch it.) 9. Never stand over the rocket.
2 empty 1.5-litre soda bottle1 cardboard
1 launch pad 1 ruler
1 bicycle pump1 clinometer
1 rolls of duct tape1 beaker (600ml)
A pair of scissorsa pair of safety glasses
1 bucket of water
Constructing the Model
1. An empty 1.5litre soft drink bottle was
cut in to half using a pair of scissors.
2. A nose cone was formed using the top
of the halved bottle.
3. A nose cone was attached at the bottom
of the other bottle.
4. Three cardboards were cut into a
trapezium shape, after that the
cardboard was wrapped with duct
tape and was attached at the top of the
other bottle to form a fin.
Experiment: Launching the Water Rocket
1. A launch pad was set in the middle of a grassy field.
2. A water was filled in the water rocket (200ml, 400ml, 600ml) 3. A water bottle filled with water was carefully placed on the launch pad. 4. A bicycle pump was used to pump air inside the water bottle. (40psi) 5. A member of the group took hold of the rope which was attached to the launch pad and moved 10metres away. 6. Another member stood 30m away from the launch site to record the angle of the water rocket using a clinometer. 7. A member counted down till the launch was...