Balloon-vacuum (Kenneth D. Howard)
Title
Balloon Vacuum
Author(s)
by Kenneth D. Howard
Principles Illustrated
Kinetic energy of molecules
Enthalpy/ Energy Transfer
Equilibrium of a system
Air pressure
The relationship between heat and the volume of gases
Vaporization of water and Condensation of water vapor
Standards
Energy is the property of many substances and is associated with heat
Heat moves in predictable ways, flowing from warmer objects to cooler ones until both reach the same
temperature.
Unbalanced forces will cause change in the direction of an object's motion
Questioning Script
Prior knowledge & experience:
All student are familiar with the properties of a balloon and how to blow it up.
Root question:
When I attach the balloon to the flask what will happen?
What is occurring when the balloon is drawn into the flask?
What is happening to the water vapor as the flask cools?
How much air is in the sealed flask?
What role does air on the outside play?
Target response:
Students will suggest the balloon will inflate.
Upon seeing the balloon going inside the students will respond that something is pulling
it inside the flask.
Common Misconceptions:
Most students will think the balloon will inflate since the flask was heated up,
they will think the hot air molecules will make the balloon expand.
The air in the flask is pulling the balloon down inside.
Photographs and Movies
References
http://www.mcrel.org/whelmers/index.asp