Grade 9 Science – Unit 2 Electricity Lesson 5
Making a Circuit
You are required to build a number of different circuits using a simple circuit board.
Materials
? Low voltage power supply
? One Voltmeter
? One Ammeter
? Three Electrical Switches
? Five Light bulbs
? Circuit board for five light bulbs
? Alligator wires (Black – LIVE, Red – Return or Neutral)
Make the following circuits
1. One light bulb
2. One light bulb controlled by a switch AFTER the light
Is there any difference putting the switch before or after the light? Explain
3.
Two light bulbs linked in ONE circuit. This is called a SERIES CIRCUIT
What happens to the brightness of each bulb compared to the one circuit light bulb brightness?
Explain
What happens when you unscrew one of the light bulbs? Explain
4.
Two light bulbs in TWO SEPARATE circuits. This is called a PARALLEL CIRCUIT
What happens to the brightness of each bulb compared to the one circuit light bulb brightness?
Explain
What happens when you unscrew one of the light bulbs? Explain
5.
Two lights bulbs in two separate circuits with each light bulb controlled by a SEPARATE
SWITCH
6.
Three light bulbs in a PARALLEL CIRCUIT
What happens to the brightness of each bulb compared to the one circuit light bulb brightness?
Explain
What happens when you unscrew one of the light bulbs? Explain
7.
Three lights bulbs with TWO in a SERIES circuit and the third linked in a PARALLEL
circuit
8.
Three lights bulbs with TWO in a SERIES circuit and the third linked in a PARALLEL
circuit AND each circuit controlled by a SWITCH
9.
Four lights bulbs in a SERIES CIRCUIT
What happens to the brightness of each bulb compared to the two circuit light bulb brightness?
Explain
What happens when you unscrew one of the light bulbs? Explain
10. Four light bulbs in PARALLEL CIRCUITS
11. Four light bulbs in PARALLEL CIRCUITS with TWO SWITCHES so that one switch
controls two light bulbs
12. Four light bulbs in PARALLEL CIRCUITS with TWO SWITCHES so that one switch
controls two light bulbs PLUS ONE MASTER SWITCH that controls all four lights
13. Five light bulbs with three in three PARALLEL CIRCUITS so one light bulb is on a
separate circuit, two light bulbs are in a SERIES CIRCUIT, and two more light bulbs are
in a SERIES CIRCUIT
14. One light bulb with a switch and VOLTMETER. NOTE: To make the voltmeter work, it
must be wired across the light bulb since the voltmeter is measuring the voltage across
the resistor (…in this case, the light bulb) or the amount of force required to move the
current through the resistance.
15. As above but with an AMMETER wired in SERIES with the switch and light. That is, the
ammeter is part of the circuit. WHY? The ammeter is measuring the electric charge
moving along the circuit.