Steam-Pressure Rocket Demonstration
The idea of using steam to produce mechanical work has been employed commercially in different fields long time ago, like the stream trains and boats. Although we might realized the power of a steam engine is not quite as powerful, we can still see the use of steam in the 21st century.
This demonstration shows that using steam from boiling water as a source of power to launch a plastic pressure rocket. The first step is to build a steam boiler. The materials needed for this boiler are as follow:
1. A Styrofoam box with a lid
2. A metal can with a lid
3. Two immersion heaters (each at 125Watt)
4. Some small Styrofoam bubbles
5. A copper connector (half inch diameter)
Drill a hole on the side (close to the top) of metal can. The copper connector is sealed at that hole with high temperature silicon. Make a hole on the side of the Styrofoam box which match the size of the connector from the metal can. Place the metal can with water inside the Styrofoam box and secure its position. Fill the rest of spaces with some Styrofoam bubble. Place the immersion heaters inside the can and cover with the metal lid. Drill another hole on the side of the Styrofoam box that is just big enough to let the heater cable wires come out. Cover the Styrofoam lid and seal the whole box with duct tape.
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The rest of the materials that needed for the demonstration are two 2.5 inches long copper pipes (half inch diameter), a ball-bearing control vault, a L-shaped copper joint and a small piece of wooden platform. The setup will look like following:
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Place the pressure rocket on the platform and plug in the power. Use the vault control as a switch to maximize or minimize the amount of stream into the rocket.
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During the preliminary testing of this demonstration setup, I found that the rocket does not move at all. The reason is twofold. First, I had found that there are places where the steam can escape from the Styrofoam box before it was directed into the rocket. For example, the place where the pipe was connected to the metal can (picture #4) and the place where the heater cable wires coming out (picture #2) from the box. Secondly, the boiler does not produce high enough pressure to push the rocket upward (i.e. the pressure of stream is much less than the atmospheric pressure). With these two reasons and the safety concern of a high pressure stream boiler in mind, I decided to use a different method to launch the rocket--simply pumping air into the rocket by a bicycle-tire pump. This pump can produce a maximum pressure at 230 pounds per square inch, more than enough to send the rocket from one end of the room to the other (during the second testing).
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Mini Conclusion:
Although the steam boiler does not produce sufficient pressure and power to launch the rocket, the bicycle air pump works surprisingly well. During the actual demonstration, the rocket flew over approximately fifteen feet away from the launching track. Improvement of the stream boiler design is a must in order to carry out the theme of the demonstration.