9
Attraction and
repulsion – charges
Jb-2
Your teacher may watch to see if you can:
●
follow instructions carefully.
Introduction
An insulating material can be given a charge of static electricity by rubbing it. The kind of charge
(positive or negative) depends on the two materials being rubbed – but rubbing together the same
combination of materials will always produce the same kind of charge on each one. So a polythene
rod rubbed by a duster will always get a negative charge.
Aim
To find out about the forces between objects with a charge of static electricity.
Method
A Hang a paper stirrup from a clamp and stand.
B Rub one end of a polythene rod with the cloth.
Put the rod in the paper stirrup without
touching the end that you have rubbed.
Apparatus
●
clamp and stand
● paper stirrup
●
two acetate rods
● cloth
●
two polythene rods
C Rub the other polythene rod with the cloth and
hold the rubbed end next to the rod in the
stirrup. Watch carefully and write your
observations in a table.
D Repeat steps B and C using two acetate rods.
E Repeat steps B and C using one acetate rod
and one polythene rod.
Recording your results
1 Copy this table to record your results.
Rod in the stirrup
Rod in your hand
Attract or repel?
2 Write a sentence to summarise your results.
Considering your results/conclusions
3 Do both the polythene rods in step C have the same charge, or different charges?
4 Do both the acetate rods in step D have the same charge, or different charges?
5 Do acetate and polythene rods have the same charge as each other? Explain your answer.
6 Copy and complete these sentences:
If two objects have the same type of charge, they …
If two objects have opposite charges, they …
Challenge
7 Your teacher may give you a rod made from a different material. Describe how you can find out
whether this material gets a positive or negative charge when rubbed.
I can…
●
recall the two types of charges and their effect on each other
●
describe an investigation to identify the type of charge on an object.
© Pearson Education Ltd 2015. Copying permitted for
purchasing institution only. This material is not copyright free.
10
9
Static questions 1
Jb-5
Name
Class
Date
1 The attraction or repulsion from static electricity is a non-contact force.
a Name the non-contact force that attracts you to the Earth.
b Name a non-contact force that only attracts objects made from certain metals.
2 Complete these sentences using words from the box. You can use each word once, more than
once or not at all.
electron
electrons
negative
equal to
no
An atom consists of a central
greater than
nucleus
less than
positive
that has a
charge.
move around the nucleus.
Tiny particles called
Each
has a negative charge.
The total amount of positive charge in an atom is usually
the total amount of negative charge, so atoms
have
overall charge.
When a material is rubbed,
The material that has gained
may be transferred from one material to the other.
now has a negative charge.
The material that has lost electrons now has a
charge.
The diagram shows two rods charged with static electricity.
3 X and Y are made of the same material.
a Will they have the same type of charge as each other,
or different charges?
b Will they attract or repel each other?
4 Rod Y is changed for a charged rod made from a different material.
When the two rods are held close together, they repel each other.
What does this tell you about the types of charge on the two rods? Explain your answer.
5 What is an electric field?
I can…
●
explain how objects can be given a charge of static electricity
●
describe how charged objects can affect each other.
© Pearson Education Ltd 2015. Copying permitted for
purchasing institution only. This material is not copyright free.
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