Balanced Forces- Balance Flask (Scott Holloway)
Author(s) Scott Holloway
Principles Illustrated
Balance and center of mass
Standards
Students know how to solve two-dimensional problems involving balanced forces (statics) .
Questioning Script
Prior knowledge & experience:
Why do you put your arms out to help you balance?
Root question:
Where is the center of mass of an object? How does an object actually balance?
Target response:
An object will balance when the center of mass is located directly over the "foot" of an object. That foot can be very narrow as long as it remains below the center of mass.
Common Misconceptions:
An object only balances on a regular (ie. flat) surface.
The center of mass is in the geographic middle of an object.
Photographs and Movies
References
http://en.wikipedia.org/wiki/Center_of_mass
http://hyperphysics.phy-astr.gsu.edu/HBASE/cm.html
http://ruina.tam.cornell.edu/Book/COMRuinaPratap.pdf