Name:
Electrostatic Fields
Procedure:
1) Use the wool to “charge” the foam pieces. Let’s say that these foam tubes now
have an excess of negative particles on them and the wool has an excess of
positive particles on it.
2) Stand the foam tube on its end. Take the small graphite covered foam ball and
brush it on the fur so that it gains an excess of positive particles on it.
3) Let’s test to see if the foam tube could be deflecting an invisible field around it.
4) First, take the uncharged foam tube, stand it on its end, and move the charged
foam ball around it. What observation do you make? ___________________
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5) To do so, move the foam ball to different points around the foam tube.
6) On the picture below, use arrows to indicate the direction and size of the motion
of the foam ball at the indicated positions.
7) If an invisible blanket were surrounding this foam tube, what would its shape be?
Sketch it below:
8) What math expression gives the size of the force exerted by the foam tube on the
foam ball at each position?
9) To determine how the field is deflected, we don’t want to consider the charge on
foam ball. In this formula, divide out the charge of the foam ball.