1. Hot Air VS Boiling Water
(Steam)
By Ethan Thomas

2. Problem
Which heat source, hot air or boiling water
(steam) will make a Stirling engine spin faster
when measured in RPM?

3. Hypothesis
Based on the research, hot air will make the
Stirling engine spin faster than the steam will.

4. Materials
• Stirling Engine (low temperature)
• Thermometer
• Tachometer
• Hot Air Source (hot air popcorn popper)
• Steam Source (mug of boiling water)
• Chart to Record Data
• Timer

5. Experiment Photos
To the right is the
Stirling engine used
in the experiment. It is
a Type B Stirling
engine.
Note: That little sliver of
tape helps the tachometer
take measurements.

6. The thermometer The tachometer

7. The Stirling engine The Stirling engine
on the hot air on the mug of boiling
water

8. Results
The Hot Air made the Stirling engine spin faster
with a top speed of 443 RPM, while the steam only
maxed out at 307 RPM.

9. Don't know enough?
http://www.absoluteastronomy.com/topics/Stirling_engine
http://www.howstuffworks.com/stirling-engine.htm
http://library.thinkquest.org/C006011/english/sites/
stirling.php3?v=2