Water Rocket Project

As part of STEM project Mr. Omer’s The Astronomy classes designed and launched water rockets on Wednesday 12th of October . The students used an empty, plastic, two-liter soda bottle as the body of the rocket. They have added a small piece of stone varying from 30-70 gram wrapped by a napkin to the bottom of soda bottle under the nose for stability in the air. 4 Cardboard fins are attached to the sides of the bottle. Three students kept a record of how long each rocket stayed in the air. Here are the top results from Georgetown and Yale

Salmon Aliyev-12.50s Georgetown

NāAjah Roseway-10.68s Georgetown

Damani Richardson -10.60s  Georgetown

Richardson, Ateeya 8.60 s

Dayzah Howard -8.37s

-Depending on the size of the bottle, the pressure between 60-90 psi is added to the bottle. 6 of 40 rockets launched landed at roof school.

 

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Water rockets are among the simplest type of rocket that a student encounters. The body of the rocket is an empty, plastic, two-liter soda bottle. Cardboard or balsa fins are attached to the bottom of the bottle for stability, and a fairing and nose cone are added to the top as a payload.

Prior to launch, the body of the rocket is filled with water to some desired amount, typically about 33% of the volume. The rocket is then mounted on a launcher. Air is pumped into the bottle rocket to pressurize the bottle and thrust is generated when the water is expelled from the rocket through the nozzle at the bottom.

Flying model rockets is a relatively safe and inexpensive way for students to learn the basics of forces and the response of a vehicle to external forces. A model rocket is subjected to four forces in flight; weight, thrust, and the aerodynamic forces, lift and drag. There are many different types of model rockets. One of the first and simplest type of rocket that a student encounters is the bottle, or water rocket. The water rocket system consists of two main parts, the launcher and the rocket.

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On the figure we show a generic launcher, although launchers come in a wide variety of shapes and sizes. The launcher has a base to support the rocket during launch. A hollow launch tube is mounted perpendicular to the base and is inserted into the base of the rocket before launch. The launch tube is connected to an air pump by a hollow feeder line. The pump is used to pressurize the inside of the body tube to provide thrust for the rocket. We have attached a pressure gage to the feeder line to display the change in pressure in the system. This part of the system is very similar to the simple compressed air rocket.

 

The other part of the water rocket system is the rocket itself. Usually the rocket is made from a 2-liter soda pop bottle. Before launch, the bottle is filled with some amount of water, which acts as the “propellant” for the launch. Since water is about 100 times heavier than air, the expelled water produces more thrust than compressed air alone. The base of the bottle is only slightly larger than the launch tube. When the rocket is placed on the launch tube, the body tube becomes a closed pressure vessel. The pressure inside the body tube equals the pressure produced by the air pump. Fins are attached to the bottom of the body tube to provide stability during the flight.

 

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