NEW ZEALAND PHYSICS TEACHERS' RESOURCE BANK

Balance a Fork and Spoon

 
Above: A version students can keep and take home | Below: A giant version.
 
Abstract
Surprising stable equilibrium point for a fork and spoon appearing to be suspended unnaturally by a match.
Portable Yes
Principles Illustrated
This fun, homemade demonstration illustrates centre of mass and also stable and unstable equilibrium.
NCEA & Science Curriculum
SCI 1.1, PHYS 2.4
Teacher Guide
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Video
Instructions

The Plastic Version:
The plastic fork and spoon version is very inexpensive. Students keep this version and take it home, helping to involve their families in their science education.

This version needs suitable plastic forks and spoons, pencils, and Blu-Tack. Assemble as is the drawing below with a small dab of Blu-Tack in the teeth of the fork to keep the fork and spoon together. Try more than one kind of plastic fork and spoon. Somewhat larger ones are better and they need to be roughly the same mass. We have found that some Basics brand forks and spoons seem to work pretty well but others do also.

Other Versions:
We have a giant version of this made with a pitchfork and shovel that seems to amuse people. Click here to see photos.

Click here for photos of a commercial device that works on a similar principle.

Click here version with metal fork and spoon will require bending the spoon somewhat.

If you have trouble getting this to work try adjusting the fork and spoon a bit.

Setup

 

References
PIRA 1J20.20
Credits

This teaching resource was developed with support from

 
Copyright

Copyright and fair use statement