Permanently Charging the Electroscope By

Induction Using a

Positively Charged Rod

title

Click here to see “traditional” grounding

at the knob

Click here to see “easier-to- understand” grounding at

the leaves

Scene 1Start off with a neutral electroscope:

Start off with a neutral electroscope:

How will the particles respond when a positively charged rod is brought near the knob?

What will the protons do?What will the electrons do?

The protons ___________ since they are locked up inside the nucleus.

Why do the leaves repel?

did not move

moved upward toward

Some of the “free to move” electrons ________________ the positively charged rod.

Like charges repel.

Scene 2To permanently charge by induction, connect a ground to the electroscope while the charged rod is near the knob.

Scene 3

Once connected, which way will the electrons travel through the ground?(from the leaves to the ground or from the ground to the leaves)

Electrons travel from the ground to the leaves

Are the leaves positive,negative, or neutral?

The leaves are neutral.

Is the overall charge on the knob positive, negative, or neutral?

The overall charge on the knob is negative.

To permanently charge by induction, which should be removed first? (click on one)

charged rod Ground wire

The leaves are neutral.

The overall charge on the knob is negative.

charged rod

If the charged rod is removed first, then the extra electrons would escape from the electroscope through the ground wire.

To permanently charge by induction, which should be removed first? (click on one)

The knob is neutral.

Try again!

The leaves are neutral.

The overall charge on the knob is negative.

To permanently charge by induction, which should be removed first? (click on one)

Ground wireThe ground wire must be removed before the charged rod.

Scene 4

Finally, the extra electrons in the knob distribute themselvesthroughout the electroscope as the charged rod is pulled away.

negatively charged knob

negativelycharged leaves

Scene 5

Like charges repel.

Recall:Was the rod used positively or negatively charged?

The rod used this timewas positively charged.

However, what was the final charge on the electroscope when charged this time?

The final charge on the electroscope was negative when charged by inductionusing the positively charged rod.

(make a note of this)