Beginner's
Guide to Propulsion
Propulsion Pop! Activity
If so instructed by your teacher, print out a worksheet page
for these problems.
Activity: Controlled
Propulsion Experiment - Film Canister
A film canister, Alka
Seltzer, and water can demonstrate how a rocket engine works. The Alka
Seltzer in the film canister, when mixed with water, produces a gas. When
there is too much gas to hold in the canister, we say there is a high
amount of pressure. This pressure needs to be released, so the lid of
the film canister pops off.
You are going to demonstrate
this and measure the distance the canister travels. Your mission, should
you choose to accept it, is to model the thrust that is produced in a
rocket.
Materials:
- film canister (generic
film type--Kodak lids are too tight.)
- drinking straw
- scissors
- string (5-8 meters
long)
- tape
- worksheet
- graduated cylinder
- water
- quarters
- safety glasses
Procedure:
- Cut a piece of
drinking straw so that it is a little shorter than the length of the
film canister.
- Tape the piece
of straw to the film canister so the straw is parallel to the canister.
(Make sure you leave enough room for the lid!)
- Slide the string
through the hole of the straw so that the lid of the canister is facing
the opposite direction of the string's path.
- Choose two people
to hold the ends of the string taut and level. Everyone MUST put on
safety glasses before continuing to Step 5!
- Put one-quarter
tablet of Alka Seltzer and 2 mL water into the film canister and quickly
close the lid. The person holding this end of the string should hold
it to the side. NO ONE should stand behind the canister.
- After a short period
of time, the lid will pop and send the canister down the string. Measure
the distance traveled and record your results on the chart shown below.
- Tape one quarter
on the end of the canister and repeat the experiment. Record your results.
- Tape two quarters
on the end of the canister and repeat the experiment. Record your results.
Number
of Quarters
|
Distance
Traveled
|
0
|
|
1
|
|
2
|
|
9. How is the Propulsion Pop! Activity similar to a rocket? How is it different?
Click Rocket Propulsion to access
information on rockets from the Beginner's Guide to Propulsion.
10. What happened
when you added one quarter? Two quarters?
11. Why do you think
your results turned out the way they did?
12. If you could modify
this experiment, what would you do differently? Be detailed in your explanation.
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