Unit 1

1. Unit 1 Lesson 2: What Makes a Circuit?

2. Objective: Series Circuit • By the end of this lesson you should be able to define a series circuit.

3. Comprehension: Series Circuit

4. Vocabulary: Series Circuit • Electric current – a flow of electric charges • Electric circuit – a continuous pathway that can carry an electric current • Series circuit – an electric circuit with only one path for current

5. Electric Current • Electric current – a steady flow of electric charges • Current electricity is used to power most electrical things • It is easier to control than static electricity

6. Electric Current • Electric currents can only move along paths • It is not random • It moves continuously, as long as there is a path to follow

7. Electric Circuit • Electric circuit – a continuous pathway that can carry an electric current • Pathways can be open or closed • Closed pathways provide usable energy

8. Electric Circuit • Circuits need a source to provide the movement of the electrical charges • A battery is an example • Two kinds of circuits: series and parallel

9. Series Circuit • Series Circuit – an electric circuit with only one path for current to flow through • An electric current must go all the way around for anything to work

10. Series Circuit: Travel of the electrical current • First the current leaves the power source • Then it travels through the wire • It passes through each attached device • Finally it ends up back in the power source • This pattern repeats as long as the pathway is closed

11. Series Circuit + + + Battery +

12. Series Circuit • Is mostly used for simple devices • Flashlights, small lighted signs, bicycle flashers • If one part of a series does not work, the whole thing will not work • Everything attached to a series circuit is on when one thing is on

13. Series Circuit • The more devices attached to a series circuit, the less effective each device is • Which circuit will have the brightest lights? Why?

14. Series Circuit • Buddy share: Would it be a good idea to use a series circuit in a house? Why or why not?

15. Comprehension Closure What is a series circuit?

16. Exploration: Series Circuit

17. Group Exploration: Making a Series Circuit • Your group will go to two different stations • You have a creation station as well as a writing station • You will have 10 minutes at each station • You will only rotate when the teacher tells you to

18. Exploration Closure: Series Circuit Draw a picture of a series circuit. Label the different pieces in your picture.

19. Comprehension: Parallel Circuit

20. Objective: Parallel Circuit • By the end of this lesson you should be able to define a parallel circuit and tell the difference between a series and a parallel circuit.

21. Vocabulary: Parallel Circuit • Parallel circuit – an electric circuit with two or more paths for current • Resistance – how much a material opposes, or resists, the flow of electric current • Short circuit – a flaw in a circuit that allows a large current to flow through where it isn’t wanted

22. Check in… • Remember that a series circuit is a circuit where there is only one path for the energy to flow

23. Parallel Circuit • Parallel circuit – an electric circuit with two or more paths for current • If one path is blocked, the charges can use another path to continue moving • It gives the electrical charges options for movement

24. Parallel Circuit • You can put many different devices on a parallel circuit • The current is split between pathways • The current can go around an object not working • Houses and buildings are wired with parallel circuits • Adding another device does not change the capabilities of other devices

25. Parallel Circuit + + + + + Battery +

26. Resistance • Resistance – how much a material opposes, or resists, the flow of electrical current • The greater the resistance, the less current can pass through • Smaller wire has greater resistance than thicker wire

27. Resistance • Which wire would be better to use? Why?

28. Resistance = Light • In a light bulb the light is actually the resistance of the electrical current • The filaments (thin wires) in the bulb has high resistance • First the filament gets hot, then it glows

29. Resistance = Light

30. Short Circuit • Short circuit – a flaw in a circuit that allows a large current to flow through where it isn’t wanted • A short circuit prevents the rest of a circuit from working

31. Short Circuit • A safety device is a fuse • A fuse has something that melts if it gets too hot and breaks the circuit • This keeps damage from happening

32. Fuse • Has anyone ever plugged something in and it doesn’t work? Why might that be?

33. Comprehension Closure: Parallel Circuits What is the difference between a series circuit and a parallel circuit?

34. Exploration: Parallel Circuit

35. Group Exploration: Making a Parallel Circuit • Your group will go to two different stations • You have a creation station as well as a writing station • You will have 10 minutes at each station • You will only rotate when the teacher tells you to

36. Exploration Closure: Parallel Circuits Draw a picture of a parallel circuit. Label the different pieces in your picture.