1. TEK 5.6 (B)
Demonstrate that the flow of electricity in circuit s requires a complete path through which an electric current can pass and can produce light, heat, and sound

2. which electricity travels Electric current The movement of electricity
Circuit
A closed path through
which electricity travels
Electric current
The movement of electricity
through an electric circuit
(the path).
Energy Source
For electricity to flow through a closed circuit, there must be an energy source, that sends out an electric current.
Important Words to Know
Example: a battery

3. Watch the circuit below.
If electricity flows through the circuit, the bulbs light up.
If electricity cannot flow through the circuit, the bulbs do not light up.

4. How was the electrical path
or circuit opened?
By removing one light bulb,the electric circuit was opened, and no light was produced.

5. And the “battery” was the source of the
electrical energy, that caused the
bulbs to light up.

6. So, remember, electrical energy, flowing in a circuit produces “light

7. Besides producing light, electricity can also produce “heat.”
What is the source of electricity for the toaster to produce the “heat” that toasts the bread?

8. For the toaster to produce heat, it needs a source of electricity .
The toaster must be plugged in to the
“wall socket” to get electricity.
Electricity comes from the power plant, through wires, to the wall socket.
And, the electricity is transformed (or changed) into “heat” to toast the bread!

9. Electricity produces, light, heat, and also… “sound!”
Electric current flows from the wall socket, through the wires, and in to the radio.
In the radio, the electricity is transformed into “sound.”

10. So, we know that electricity produces, light, heat, and sound
So, we know that electricity produces, light, heat, and sound. And it can also produce “magnetic effects!” HOW?
“Electromagnets”

11. “Electromagnets”
A temporary magnet can be made by passing electric current through a wire coiled around an iron bar.

12. “Electromagnets”
A junkyard is one place to see an electromagnet in action.
A crane holding a huge electromagnet can be used to pick up scrap metal when current flows through it. When the crane operator wants to drop the scrap, he or she will simply shut off the current to the electromagnet.

13. So we know that electricity can flow in a circuit and produce…
light
heat
sound
magnetic effects

14. Let’s Review Question #1

15. A. Battery B. Magnet C. Television D. Wall Outlet
In order to watch the television below, what is the source of electricity for this circuit?
A. Battery
B. Magnet
C. Television
D. Wall Outlet

16. Correct Answer Choice:
D. Wall Outlet
The source of electricity for this electric circuit is the wall outlet.
Placing a plug into a wall outlet allows you to get the electricity. (Electricity comes from the power plant to your house.)
Electricity travels through the outlet, through the wires in the television’s cord, to the television, and back again.

17. Incorrect Answer Choice:
A. Battery: There is no battery in this circuit.
A battery is in this kind of circuit.

18. Incorrect Answer Choice:
B. Magnet: Although there is a magnet inside the TV, it is not the “source” of electricity.

19. Incorrect Answer Choice:
C. Television: The television is in the circuit, and it changes electricity into light and sound. But it is not the “source” of electricity, like the wall socket.
Source

20. Let’s Try
Question #2

21. 2. Which of the following transforms electrical energy to heat energy?B. C. D.

22. Correct Answer Choice:
B. toaster
Do you like your bagel toasted?
Electric current flows into the toaster and passes through coils that heat up. These heated coils toast the bread.
The toaster changes the electricity into heat.
Hint:If you see a plug, you know it needs electricity.

23. Incorrect Answer Choice:
A. wind turbine
The wind turbine transforms
wind energy into electrical
energy. It does not involve
heat.

24. Incorrect Answer Choice:
C. flash light
A flash light changes electrical energy into light, not heat.

25. Incorrect Answer Choice:
D. fire
A fire makes heat, but it does not use electrical energy to make the heat.

26. Let’s Try
Question #3

27. C. have two north poles attract D. be made of materials such as wood
3. One difference between an electromagnet and a bar magnet is that the magnetic field produced by an electromagnet can __ ?
A. be made permanent
B. be turned on and off
C. have two north poles attract
D. be made of materials such as wood

28. Correct Answer Choice:
B. be turned on and off
The magnetic field of an electromagnet is a result of the electric current in the wire. Since the electric current can be switched on and off, so can the electromagnet.

29. Incorrect Answer Choice:
A. be made permanent
Bar magnets stay magnetic for a long time and cannot be turned on and off.
N S

30. Incorrect Answer Choice:
C. have two north poles
All magnets, including electromagnets have one north pole and one south pole.

31. Incorrect Answer Choice:
D. attract material such as
wood
Since wood is not magnetic, it will not be attracted by either a bar magnet or an electromagnet.
(Iron is magnetic, not wood.)

32. And finally,
Question #4

33. D. electricity to motion
4. Which of the following examples below is an energy change that is needed to listen to a radio?
A. electricity to sound
B. electricity to light
C. electricity to heat
D. electricity to motion

34. Correct Answer Choice:
A. electricity to sound
When the radio is plugged in, electricity is changed into sound energy that travels from the speaker to your ears.

35. Incorrect Answer Choice:
B. electricity to light
A clock radio does produce light, but to hear a radio, the radio must produce sound.

36. Incorrect Answer Choice:
C. electricity to heat
The question is asking what
is needed to “hear a radio.”

37. Incorrect Answer Choice:
D. electricity to motion
The question is asking
what is needed to “hear a
radio.”

38. In summary, electricity can flow in a circuit and can produce … -light -heat -sound