The document discusses electrical charges, noting that there are two types - positive and negative - and that opposites attract while likes repel. It explains how some materials are more likely to take on or lose negative charges than others according to their placement in the electrostatic series. Various examples are provided to illustrate the concepts of attraction and repulsion between charged objects.

1. Electrical Charges
Objectives:
4.4 Demonstrate that there are two
types of electric charges – (after
doing experiments &
documentary research)

2. Electrical Charges:
 All matter has electrical charges
 There are two types of charges:
 Positive +
 Negative
-
 If you have an equal number of
positives as negatives, makes
neutral

3.  There are 2 forces between charged
objects:
Attraction Repulsion
 Opposite charges  Same charges
 “Opposites Attract”  “Like repel”

4. Sphere A is negatively charged.
When placed beside sphere B, they attract.
What is the charge on B?
POSITIVE
Opposites
Attract!
AA B
- +

5. Three charged spheres are suspended
next to each other.
If sphere A is negatively charged,
what will happen when sphere A & C are
suspended beside each other?
Attract
A B B C A C

6. Four charged spheres are suspended next
to each other.
What will happen if A & D were suspended
next to each other?
Repel
A B B C C D
+ + + - - +

7. You have three charged
objects – A, B & C in a lab.
You record the following
results:
Test Observation
Bring “A” near “B” They repel
+ +
Bring “A” near “C” They attract
+ -
+ -
What would happen if “B” & “C”
were brought together?
They would attract!!!

8. Electrostatic:
 All objects begin neutral & can
become positively or negatively
charged
 A positively charged object has more
positives than negatives
 A negatively charged object has more
negatives than positives

9. Only negative charges move!
Electrostatic Series:
Positive charges NEVER move!!
 Electrostatic series is a list that ranks
objects’ ability to take negative
charges
Rubber
Items at top
Ebonite
take negatives
Polyethylene
Cotton
Silk
Wool
Glass Items at bottom
Acetate lose negatives
Fur / Hair

10. Items at top
take negatives
Your cat rubs against a rubber balloon.
What will be the charge on the balloon?
Your cat’s fur?
Rubber
Rubber
Rubber balloon
Ebonite becomes
Polyethylene negative
Cotton
Silk
Wool Cat’s fur
Glass becomes
Acetate positive
Fur/ / Hair
Fur Hair Negatives

11. Items at top
take negatives
In a lab, you take a piece of neutral wool
& neutral polyethylene & rub them
together. What will be their charges?
Rubber Polyethylene
Ebonite balloon
Polyethylene
Polyethylene becomes
Cotton negative
Silk
Wool
Wool Negatives
Wool
Glass
becomes
Acetate
Fur / Hair positive

12. In a lab, you rub a piece of
cotton & ebonite together.
Then you rub a piece of silk
& glass together.
You then bring the charged piece of
cotton & the charged piece of silk
together. What will happen?
Rubber
- Ebonite
Polyethylene Cotton is +
+ Cotton
- Silk Silk is -
They
Wool
+ Glass
would
Acetate ATTRACT
Fur / Hair

13. You rub your hair with a balloon.
Explain using words & pictures,
why your hair “sticks up”.
1st Hair & balloon are _
+_ _
both neutral
+ +
2nd Rubber balloon takes
negative charges from the
hair. So, balloon becomes
negatively charged & hair
becomes positively charged _ +_
+
3rd Since hair is positive &
like charges repel,
hair sticks up!!!

14.  Two types of charges – positive (+) &
negative (-)
 “Opposites Attract”
 “Like Repel”
 Items at the top of the electrostatic
series list take negative charges
 Only negative charges move

15. Activities
 Physical Science Worksheet #5

16. References
 Student Study Guide – Physical
Science 416/436 - MEQ
 Science Quest – Grenier, Daigle,
Rheaume – 1998, Cheneliere
 Google Images
 Animation Factory