What Forces Are There Between Objects Charged with Static Electricity?

What forces are there between objects charged with static electricity?

Apparatus

clamp and stand paper stirrup two acetate rods two polythene rods cloth

Method

A Hang a paper stirrup from a clamp and stand.

B Rub a polythene rod with the cloth. Without touching the end you have rubbed, put it carefully in the stirrup as shown in the diagram.

C Rub the other polythene rod with the cloth.

D Hold the rod so that one end of it is near the rod in the stirrup, as shown in the diagram.

E Do the two rods attract or repel each other? Write your observation in the results table.

F Repeat steps B to E using two acetate rods.

G Repeat steps B to E using one acetate rod and one polythene rod.

Recording your results

1 Copy this table for your results:

Rod in the stirrup / Rod in your hand / Attract or repel?
polythene / polythene
acetate / acetate
acetate / polythene
polythene / acetate

2 Do the two polythene rods in step E have the same charge as each other, or different charges? Explain your answer.

3 Do the two acetate rods in step F have the same charge as each other, or different charges?

4 Do you think the acetate rod and the polythene rod in step G have the same charge as each other? Explain your answer.

Considering your results/conclusions

5 Copy and complete these sentences:

If two objects have the same type of charge, they …

If two objects have opposite charges, they …

This document may have been altered from the original.

1 Complete the labels on this diagram of an atom.

2 Which particles are transferred when an object gets a charge of static electricity?

¨ atoms ¨ protons ¨ neutrons ¨ electrons

3 You rub a plastic rod with a cloth. The plastic rod ends up with a positive charge. Which of these statements are correct?

¨ Negatively charged electrons have been transferred from the cloth to the rod.

¨ Negatively charged electrons have been transferred from the rod to the cloth.

¨ Positively charged protons have been transferred from the cloth to the rod.

¨ Positively charged protons have been transferred from the rod to the cloth.

¨ The rod now has more electrons than it started with.

¨ The rod now has fewer electrons than it started with.

¨ The rod now has more protons than it started with.

4 The diagrams show different charged objects. Write attract or repel under each diagram.

This document may have been altered from the original.

1 Draw a sketch of an atom and label the nucleus, a proton and an electron.

2 Clothes taken from a tumble dryer often have a static charge. Explain why this happens.

3 A glass rod and a polyester rod are both rubbed with a cotton duster and suspended as shown. The polyester rod gets a negative charge and the glass rod gets a positive charge.

a Explain what has happened to give the glass rod a positive charge.

b Will the suspended rods attract or repel each other?

c If you rub two identical rods with the same cloth, they will always repel each other. Explain why this is so.

4 You rub a balloon on your jumper and the balloon gets a negative charge. The charged balloon will stick to a wall. Explain why this happens.

Extra challenge

5 A furniture polish says on the can that it has an 'anti-static' effect.

a Explain why an anti-static effect is needed in furniture polish.

b Find out how it works.

This document may have been altered from the original.