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Inertia - Hoop and Coke Bottle (Nadia Chocron)


Nadia Chocron

Principle(s) Illustrated

  1. Inertia - The resistance of an object to change its' motion


  • 8.2.e - Students know that when the forces on an object are unbalanced, the object will change its velocity.
  • 8.2.f - Students know the greater the mass of the object, the more force is needed to achieve the same rate of change in motion.  

Questioning Script

Prior knowledge & experience:

Students know that when objects are moved, other objects are affected.  They do not understand that the reason objects move is because of the forces acting on objects, not only the act of touching.   

Root question:

What will happen to the crayon if the hoop is removed?

Target response:

The crayon will fall into the coke bottle because the forced acting on the crayon did not change.  The forces wee acting on the hoop, not the crayon.  

Common Misconceptions:

Students believe that the crayon will move with the hoop when it is removed.  They do not believe that it will fall into the coke bottle.  

Photographs and Movies

The hoop is balanced on the top of a coke bottle.  On the top of the hoop is a crayon.

When the hoop is removed, the crayon's inertia did not change.  The crayon falls into the bottle and does not go with the hoop.  


Inertia Demonstrations

Inertia Demos