Magnetism

1. HOW DO WE USE ELECTRICITY AND MAGNETISM?
(PART 1)
C H A P T E R 1 2 : L E S S O N 5 :

2. WHAT IS MATTER?
Matter is everything around us that has
mass and volume
WHAT IS MATTER MADE OF?
Matter is made of very small building blocks
called ‘ATOMS’

3. WHAT ARE ATOMS?
Smallest part of any matter
Cannot be seen with a normal microscope
(use electron microscope)
Example:
Oxygen
Hydrogen
N.B. Water (H₂O)is made of 1 atom of oxygen and 2
atoms of hydrogen)

4. WHAT DO ATOMS LOOK LIKE?
Matter is made up of atoms.
+
+
+
–
––
+
–
Proton (positive charge)
neutron (neutral)
electron (negative charge ,Electrical charge)
atom nucleus

5. WHERE DO CHARGES COME FROM?
If electrons = protons neutral ,So atoms are neutral
If electrons > protons  gaining electrons, negative charge,
electrical charge
If electrons < protons  losing electrons, positive charge

6. Positive and Negative
Charge
Opposites charges attract
Same charges repel

7. CHOOSE THE CORRECT ANSWER
1) Matter is made up of tiny particles called .
A) atoms
B) balls
C) hoops
2) Inside the atom, there are and charges.
A) positive and positive
B) negative and negative
C) negative and positive

8. 3) When the positive charges are equal to the negative charges, matter is
_______________ .
A) positively charged
B) neutral
C) negatively charged
4) charges move easily than _____________
charges.
A) negative, positive
B) positive, negative
C) neutral, positive

9. 5) Negative and positive = __________
A) Attract
B) Repel
C) No change

10. ELECTRICITY IS DIVIDED IN TO 2 TYPES:
1.Static electricity 2. Current
electricity
(A flow of electrical
charges
through a path way called :
circuit)

11. 1.STATIC ELECTRICITY
The build up of an electric charge on the
surface of an object.
The charge builds up but does not flow.
Static electricity does not move. It is
stored.

12. ELECTRONS…
Are located on the outer edges of
atoms…they can be moved.
A concentration of electrons in an atom
creates a net negative charge.
If electrons are stripped away, the atom
becomes positively charged.

13. EXAMPLES OF
STATIC
ELECTRICITY

14. When a balloon rubs a piece of wool...
– electrons are pulled from the wool to
the balloon.
The balloon has more electrons than usual.
+
+
+
+
+
–
–
–
–
–
The balloon: – charged,
The wool: +charged
wool

15. Try rubbing a balloon
against a wool cloth
Place the balloon
over anybody’s hair
and watch what
happens
BALLOON EXPERIMENT

16. When we rub the
balloon against a
wool cloth, the
balloon gains a
negative charge (-)
The (-) charge in the
balloon attracts the
(+) charge in the hair
causing the hair to
stand.
EXPLANATION

18. THE PRODUCTION OF A CHARGE IN AN UNCHARGED BODY
BY BRINGING A CHARGED OBJECT CLOSE TO IT
When negatively charged rod is put near a metal can...
electrons of the can are pushed away fro
the rod.
 top of the can: positive
& attraction > repulsion
+
+ + +
+
metal can - -
-
-
-
----- --
buttom of the can: negative
induced
charges attraction
repulsion

19. ATTRACTION OF UNCHARGED OBJECTS
Similarly, when charged rod is close to paper scrap...
----- --
molecules of paper align.
 attraction between the rod and
+ charge > repulsion between the
rod and - charge.
paper +
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
attraction
repulsion

20. Try rubbing a comb
against a wool cloth
The comb will gain
a negative charge
Bring the comb near some pieces of paper
COMB EXPERIMENT

21. Initially the paper is uncharged, but
the comb attracts the positive
charges in the paper and repels the
negative charges.

22. Lightning
(Is caused By)
Rubbing of rain drops and
ice inside a storm cloud
When the (-) charges get
large enough they jump to
the ground as lightning.

28. 3)The _________charges on the
balloon attract the _________
charges on the wall . The balloon
sticks to the wall.
1)A balloon and wool cloth
are ____________.
2)By rubbing the balloon
with the
wool,_____________
charges goes to the balloon.
COMPLETE:

29. THE END

30. CURRENT ELECTRICITY
(CURRENT ELECTRICITY)
•A flow of electrical charges through a circuit.
(Circuit is a path along which electric current
flows)

31. Circuits should have 3 parts
Power source
Battery (cell)
Load
Bulb / Motor
Connectors
Wires
Power source
Load
Connectors

32. Types of circuits
Open circuits
Broken circuits
(Incomplete)
Closed circuits
Unbroken circuits
(Complete)

33. CIRCUITS’ SYMBOLS:
1) Battery

34. 2) Bulb

35. 3) Wires
(A straight line)

36. 4) Switch (off)

37. 5) Switch (on)

38. 6) Motor
7) Buzzer

39. The end

40. SERIES AND PARALLEL
CIRCUITS

41. SERIES CIRCUIT
Series circuit - has only one path through
which the electricity can flow.
In the above diagram, the electricity flows
through both loads.

43. PARALLEL CIRCUITS
A parallel circuit has multiple paths through which the
electricity can flow.
In a parallel circuit, the current though one path may be
different than the current through the other path.

44. PARALLEL CIRCUIT
Place two bulbs in parallel. What do you notice about the
brightness of the bulbs?
Add a third light bulb in the circuit. What do you notice about the
brightness of the bulbs?
Remove the middle bulb from the circuit. What happened?

45. SIMPLE CIRCUITS
Series circuit
All in a row
1 path for electricity
1 light goes out and the
circuit is broken
Parallel circuit
 Many paths for electricity
 1 light goes out and the others
stay on

46. Conductors and Insulators
A conductor is a substance through which electric
charge flows readily.
An insulator is a substance that strongly resists the flow
of electric charge.