MS - PS3.B (A) - Energy Transfer in Motion - FINAL (WND 1/28/2014)

DCI: PS3.B (A):  When the motion energy of an object changes, there is inevitably some other change in energy at the same time. (MS-PS3-5)

PE: MS-PS3-5.        Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object.

[Clarification Statement: Examples of empirical evidence used in arguments could include an inventory or other representation of the energy before and after the transfer in the form of temperature changes or motion of object.] [Assessment Boundary: Assessment does not include calculations of energy.]

The ideas we se in this standard are: 

- any change to an object's motion coincides with some other change in energy simultaneously. 

When they say the motion energy of an object, I think what they mean is the object's kinetic energy (not kinetic energy of particles).  

We can use temperature changes and changes in an object's motion as evidence that energy has changed.  

Possible Question Starters: 

"A ball is rolling across the floor.  As it slows to a stop, its thermal energy increases due to the force of friction. Which of the following would demonstrate a transfer of thermal energy from the ball to its surroundings?"

correct answer - the surface of the floor where the ball rolled past is a little warmer than other parts of the floor

incorrect answer - the shape of the ball gets a little rounder when the ball comes to a complete stop

"Two spheres are moving towards each other.  When the spheres collide, which of the following will take place?"

Correct answer - each sphere will transfer some of its energy to the other sphere

incorrect answer - each sphere will suddenly stop moving