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Rogue Physicist.  Free resources for physics education © 2006-2016 Dorian Pascoe.  Email: dorian.pascoe@hotmail.co.uk

Most resources are available under a Creative Commons Licence.  Visit our mirror at www.physicsweb.altervista.org

 

 

Electrostatics

 

Objectives

• Know that there are two types of electrical charges

• Know that negative charges are small and light, and that charges can be transferred by friction.

• Be able to describe and explain processes involving the transfer and interaction of charges, using correct technical language.

 

 

 

Task 1

Remind the person next to you:

• What are the two types of electrical charge?

• How could someone become charged with static electricity?

• What does the word static mean?  Can you think of somewhere the word static is used which is not referring to electricity?

• Which type of charge is small and light?  (hint: think about your work on atomic structure in chemistry lessons!)

 

 

 

Task 2

Think about a time when you have had a shock from static electricity.  What were you doing at the time?  What could have caused the static shock?  Your teacher will ask some of you to share your ideas with the class, and show you the simulation below, which helps explain how static shocks  occur.

 

n.b. there is also a local copy stored here.

 

 

Task 3

Look at the simulation below, which shows how two insulators can be charged by rubbing them against each other.  In this case, a balloon is charged up by rubbing it on a jumper.

n.b. there is also a local copy stored here.

 

 

Task 3

Complete the sentences below:

 

The two types of charge are ___________ and __________.

 

__________ charges are much smaller and lighter than _________ charges.

 

Charges can be transferred between insulators by _________.

 

If an object has _________ numbers of ________ and _______ charges it is 'uncharged' or 'neutral'.

 

An object with an ________ of positive charges is 'positively charged', and an object with an excess of ________ charges is negatively ________.

 

Opposite charges __________ and like charges ___________.

 

 

Now copy and complete the table:

 

Combination of charges

Attract or repel?
positive and positive  
negative and negative  
positive and negative  

 

 

 

 

 

Task 4

Write an explanation of what happens when a balloon is charged up by rubbing it on a jumper.  Use the following terms in your explanation:

 

charge         positive          negative          neutral          uncharged          equal          transfer          friction          charged           light          small          build-up          gained         excess          lost       deficit          insulator          attract

 

 

 

 

 

 

Task 5

Your teacher will demonstrate a Van de Graaff generator, which is very effective at transferring charge.

 

Listen carefully as your teacher explains how the Van de Graaff generator works.

 

Your teacher may show you some of the following demonstrations:

  • A person being charged up.

  • Sparks jumping from one person to another.

  • A stack of foil pie cases being charged up.

  • Soap bubbles being repelled.