PS AR RS P5L30 Electrical System 4 WS

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Topic: ELECTRICAL SYSTEM 4 (LESSON 30)

Rocket Science | Primary 5

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Primary 3: Rocket Science

Lesson Outline

• Notes
• Activity 1: Hands-on Activity
• Activity 2: MCQS
• Activity 3: Open-ended Questions
• Activity 4: Fun Facts

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Primary 5: Rocket Science

VIDEO: Circuits in Holiday Lights.

https://www.youtube.com/watch?v=x9s_SIBIbwI
Discussion Question:

1. How do the series circuit and parallel circuit work?

2. What happens to each electrical circuit if one bulb is burned out?
3. Which type of circuit is more advantageous to use in holiday lights?

Why?

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Primary 5: Rocket Science

Series and Parallel Circuit - Notes

There are two ways to arrange the components of an electric circuit. Each has
different effect in the current and in the load.

A circuit in which the components are connected from end-to-end are called

. This provides a single path for or the flow of

electrons. The bulbs in this circuit share an equal current. So, if you have two

bulbs, the current will be divided equally to the two bulbs.

Series circuit

Since electricity flows from the source Series circuit with one bulb busted
to each load one at a time, in the Light produced in series circuit
order they are wired to the circuit, if
one of the bulbs blew out, the other
bulbs would not be able to light up.
This is because the current is
interrupted and the circuit is open.

Adding more batteries in a series

circuit will produce light

while adding more bulbs will produce

light. This is because the

bulbs in a series divides the electric

current more, thus, each light will

receive less current.

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Primary 5: Rocket Science

Series and Parallel Circuit - Notes
In circuit, there are multiple paths through which electrons can flow.

Parallel Circuit

In this circuit, the electric current has more than one path to travel. So, if one
bulb blew out, the other bulb would still be able to light up because the current
will still flow to the good bulb.

Each bulb receives the same amount of current that leaves the battery. Current is
not divided into the number of bulbs or load. Adding more bulbs will not affect the
current and all bulbs will have the same brightness. However, this will consume
the battery faster than it is in a series circuit.

Adding more batteries in this circuit will give brighter light but there is a limit. The
bulbs have limited current capacity. If there is too high current flowing though the
bulb it might blow out or get busted. Before adding more batteries take a look at
the limit of current that the bulb can hold to avoid getting busted.

How will you arrange the lights in this
keyboard? What do you think is the best
way to connect them?

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Primary 5: Rocket Science

Activity 1 – Hands-on Activity: Series and Parallel Investigation

Material:
LED Light (3 pcs)
Copper tape (0.5 cm width, the shorter it is, the better.)
3-Volts Coin Cell Battery (2 pcs)
Construction paper

Instructions:

1. Put the copper wire on the construction paper as indicated on the diagram
below.

Battery Long strip A Z
End of long strip B
XY

Long strip B

2. Put 2 LED Light in the space X and Y. Then, connect the end of Long
strip B.

3. Add another bulb in gap Z and observe if there are any changes in the
brightness of the bulbs.

4. Add another battery to the circuit and observe what changes will happen
in the negative terminal of the battery. Make sure the positive terminal of
the battery is connected to the negative terminal of the other battery.

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Primary 5: Rocket Science

5. Follow the illustration for the Circuit B. You may use the LED light used in
Circuit A.

Battery

6. Connect the end of the copper tape to the battery. Observe the brightness.

7. Disconnect Bulb B, and connect the end of the tape to the battery. Observe
what happens.

8. Return Bulb B to the circuit. Then, create a gap before Bulb A and connect
another LED light. Observe brightness of the bulbs.

Bulb A Bulb B
Battery

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Primary 5: Rocket Science

9. Add another battery to the circuit. Observe what happens to the
brightness of the bulb.
(a) How does the brightness of Circuit A and B differ after adding another
bulb?

(b) Why do you think Circuit B did not work when removing one bulb
unlike in circuit A?

(c) How does adding a battery affect the brightness of the bulb in each
circuit? Which circuit produced brighter light?

(d) How would you compare the route of current in each circuit?

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Primary 5: Rocket Science

Activity 2 - MCQs

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Primary 5: Rocket Science

1. In the given circuit below, all the bulbs do not light up when two of the bulbs are not
working.

D C

B
A

Which two bulbs are fused? ()

(1) A and C only
(2) A and D only
(3) B and D only
(4) C and D only

2. Study the circuit diagrams below.

T U
S

Which of the following will have the brightest light and the dimmest light? ()
(1) T is the brightest and S is the dimmest
(2) S is the brightest and T is the dimmest 9
(3) U is the brightest and S is the dimmest
(4) T is the brightest and U is the dimmest

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Primary 5: Rocket Science

3. Study the circuit diagrams below.

Circuit E Circuit F

Circuit G Circuit H

Which of the following circuits correctly match the experimental problem?

Set-ups Experimental Problem
(1) E and G
(2) E and H How does the number of bulbs affect the
(3) F and G brightness of the bulbs?
(4) F and H
How does the arrangement of the bulbs
affect the brightness of the bulbs?

How does the number of bulbs affect the
brightness of the bulbs?

How does the arrangement of the bulbs
affect the brightness of the bulbs?

()

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Primary 5: Rocket Science

4. Study the diagram below. Switch A Room 1
Switch B Room 2
Electricity
supply

Room 4

Room 3

Based on the diagram above, which of the following is correct about the electrical circuit
Is correct?

(1) If only switch A is closed, all the bulbs in the rooms will light up.

(2) If only switch A is opened, the bulbs in rooms 3 and 4 will light up.

(3) If only switch B is closed, the bulbs in rooms 2, 3, and 4 will light up.
(4) If only switch B is opened, all the bulbs in the rooms will not light up. ( )

5. Study the circuit below. P

S1 Q R S2 S4
T U S3
()
V S5
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Which bulb/s will light up if only S1, S2 and S5 are closed?
(1) Only V and P
(2) Only Q, R and P
(3) Only V, Q, R, and P
(4) Only V, T and U

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Primary 5: Rocket Science

6. Study the electrical circuit below.

When two bulbs fused, the other bulbs remained lighted up. Which were the two bulbs that
had fused?

(1) A and B ()
(2) A and D
(3) B and C
(4) C and D

7. The diagram below is a circuit with three identical bulbs X, Y, and Z.

X

Y

Z

Which of the following statement is correct about the circuit above is correct?

(1) The switch controls bulb X and Z ( )
(2) Bulb X, Y, and Z are arranged in series.
(3) When bulb X fuses, bulb Y and Z will remain lit.
(4) There are four batteries in the circuit connected in series.

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Primary 5: Rocket Science

8.. Which of the following will light the most number of bulbs when only one switch is
closed?

()

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Primary 5: Rocket Science

9. Study the diagram below.

In which order would you close the switches so that the Bulb A lights up first, followed by
Bulb B and then Bulb C?

1st switch to close 2nd switch to close 3rd switch to close
Z
(1) X Y X
Z
(2) Z Y Y

(3) Y X

(4) Z X

()

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Primary 5: Rocket Science

10. Which of the following actions illustrate the safe handling of electrical parts?

A. Do not touch switches with wet hands
B. Replace wires when rubber insulation is damaged
C. Connect as many plugs as possible to one socket
D. Connect the plug to the socket when the switch is turned off

(1) A and C only
(2) B, C, and D only
(3) A, B, and D only
(4) A, B, C and D

( )

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Primary 5: Rocket Science

Activity 3: Open-ended questions

1. Study the diagram below. Circuit X bulb A
bulb A

bulb B

(a) Will Bulb A remain lit when Bulb B is removed as shown? Give a reason for your

answer. [1]

bulb A Circuit Y bulb A

bulb B

(b) Will the observation be the same in Circuit Y? Explain. [1]

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Primary 5: Rocket Science

2. Study the three circuits below.

P

S1 Q R S2

T U S3

V S5 S4

(a) Which switch/es must be closed to make Bulb T and Bulb U light up? [1]

(b) If all the switches are closed, which bulb, when fused, will cause all the other bulbs

not to light up? [1]

(c) Which bulb/s will light up if Bulb R is fused and only S1, S2, and S3 are closed? [1]

118 7

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Primary 5: Rocket Science

ACTIVITY 4: Fun Facts – The Electric Fish

https://www.youtube.com/watch?v=z0M7_HPSi14

Discuss Answer

Before the video Are there fishes that could
produced electricity?
0:29
1:12 How do electric eels use
4:36 electricity?

How do fishes create electricity?

Why do electric fish not
electrocute themselves?

119 8

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