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Demos: 1H-04 Hero's Engine


A large glass bulb having nozzles attached to the side is filled partially with water. The entire apparatus is suspended in a low-friction bearing so that it can turn easily. As the water is heated to boiling, steam is ejected from the nozzles whose tips are oriented tangential to the tube’s sides. The reaction force to the ejection of the steam spins the bulb.

Directions: Start the burner under the bulb a few minutes prior to the time you want to present the demonstration. Stand back from the apparatus to avoid potential steam burns.

Suggestions for Presentation: This is fairly straight forward. Discuss action-reaction forces ahead of time and emphasize what is happening at the nozzle tip when the steam commences.

Applications: Compare this with a lawn sprinkler that operates with a spinning nozzles. You might also discuss what can happen to rockets when the exhaust ports are not aligned properly.

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Last Updated: Jul 23, 2019 10:14 AM

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