CHARGING BY INDUCTION ANIMATION -how electrons move

The first powerpoint is designed to show how the conduction electrons behave when a metal sphere is charged by induction.
Rather than just describing what happens students can clearly see how the electrons move.
It shows a metal sphere with positive ions fixed in position and negative conduction electrons.
It illustrates how the conduction electrons move when a negative rod is moved towards and away from the sphere.
It then shows how the conduction electrons behave when a negative rod is brought close to the sphere which is then briefly connected to earth. The negative rod is then removed, leaving the sphere positively charged.
The above is repeated but this time with a positively charged rod which is used to give the sphere a negative charge by induction.
The second powerpoint is a simple example of inducing a charge.
It shows how electrons are attracted to the top of a tree when a positively charge cloud moves overhead and then return to earth when the cloud moves away.