Changing%20Electrical%20Energy - PowerPoint PPT Presentation

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Changing%20Electrical%20Energy

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Changing Electrical Energy Lesson 4 Ended here * * Changing Electrical Energy Electrical devices change electric energy into a form of energy we can use. – PowerPoint PPT presentation

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Title: Changing%20Electrical%20Energy


1
Changing Electrical Energy
  • Lesson 4

2
Changing Electrical Energy
  • Electrical devices change electric energy into a
    form of energy we can use. This change is called
    an Electrical Conversion.
  • -Example A light bulb converts electrical energy
    into light energy.

3
  • Other useful forms of energy include heat energy,
    sound energy, and energy of motion. Consider how
    each of the following tools is used. Identify
    what form of energy is produced.

4
What form of energy is produced?
  • Heat

5
What form of energy is produced?
  • Motion

6
What form of energy is produced?
  • Sound

7
What form of energy is produced?
  • Motion
  • Heat
  • Sound

8
Electric Motor
  • An Electric Motor is a device that converts
    electricity into movement by creating an
    electromagnet. Any electrical device that has
    moving parts will have a motor of some sort.
  • Example Electric tooth brush, electric drill,
    and an electric car.
  •  

9
Electric Heater
  • An Electric Heater is a device that converts
    electricity into movement. All electrical devices
    give off some heat. A heater works by sending
    more current through a wire than it can handle.
    This causes the wire to heat up. This is
    potentially dangerous as it can start an unwanted
    fire.

10
Sound
  • Sound is generated in speakers by the use of
    electromagnets which are moved by changing the
    direction of the current. This causes the
    speakers to repel and attract. The movement
    creates sound.

11
What is the Source?
  • Electric energy comes from different sources. The
    source in an electric circuit converts another
    form of energy into electric energy. A battery
    converts chemical energy to electrical energy.

12
What is the Source?
  • In a flashlight, the electric energy converts to
    light energy. Power plants convert chemical
    energy or energy of motion into electrical
    energy. This energy flows through electric
    circuits into the devices you use at home.

13
For the diagram to the right, add the following labels Chemical energy ? electric energy Electric energy ? light energy
14
Circuit Safety
  • It is important to know how to build and use a
    circuit properly. A poorly connected circuit can
    damage equipment or injure people.
  • A circuit that creates a risk of damage or injury
    is called an electrical hazard.

15
Lab-Find out why a badly connected circuit is an
electrical hazard.
  • Safety precaution
  • Do not hold the foil in place on the battery for
    more than 10 seconds.
  • Clean up your work area and put away all
    equipment after this activity.

16
  • Procedure
  • Fold the aluminum foil so that it touches both
    terminals of the battery.
  • Hold the foil in place for 5 seconds. Observe
    what happens. Then remove the foil.

17
What did you find out?
  • Is the circuit open or closed? Open / Closed
  • How do you know?
  • What happens to the electric energy in this
    circuit?
  •  
  •  
  • How could this kind of circuit be dangerous?

18
Short Circuit
  • When you connected the two battery terminals with
    foil, you created a short circuit. A short
    circuit is a circuit with no useful load. Instead
    of flowing through a useful load, electric
    current flows from the source through the
    conductor and back to the source.
  • In a short circuit, the conductor becomes the
    load. Electric energy is converted into heat in
    the conductor. The conductor gets hot and may
    even catch fire. A hot or smoking conductor is a
    sign of a short circuit.

19
Circuit A. This circuit is safe to work with. Circuit B. In this circuit, the insulation around the wire is damaged where the wires cross. This is a dangerous short circuit.
20
  • Why is circuit B unsafe?
  •  
  •  
  • Why wouldnt the bulb light up if this circuit
    was created?

21
Building Circuit Safety
  • Safety Comes first
  • Check all your equipment and replace damaged
    equipment.
  • Remove all metal jewellery
  • Make sure your work area is clean, dry, and
    uncluttered.

22
  • Connect loads in order
  • Connect one end of a wire to the positive
    terminal of the battery
  • Connect components one at a time
  • Complete the circuit by connecting the free end
    of the last wire to the negative terminal of the
    battery.
  • If you are connecting one wire to another, use
    the alligator clips to hold the wires together.

23
  • Face all batteries the same way
  • If you are connecting batteries together, always
    connect the positive terminal of one battery to
    the negative terminal of the next battery.

24
  • Keep Switch off.
  • Always keep the switch in the off position
    until the circuit is complete. When you are ready
    to use your circuit, turn the switch on. Turn it
    off when you are finished.

25
Testing Circuits
  • Imagine you have just purchased a gaming system.
    You connect all of the wires, turn it on and,...
    nothing happens. Something is not working. How
    can you identify the problem?
  •  
  • A Checklist is a set of questions you can use to
    check for problems. You can use a checklist to
    make sure an electric circuit is connected
    properly. If your circuit is not working, a
    checklist will help you find the problem.

26
Checklist
  • A circuit checklist is a set of three main
    questions.
  • Is the circuit complete? Check to make sure that
    your circuit has a source, a useful load, and
    conductors.
  • Is the switch closed? Check to make sure that the
    switch is in the on position.
  • Are all the wires properly connected? If the
    wires are not properly connected, make sure that
    the switch is off before connecting the wires
    properly. Then close the switch and check and
    again.

27
  • Look at the circuit diagrams below.
  • Predict whether or not you think the bulb will
    light up by using the three questions from the
    checklist.
  • Set up the circuit and see if you were correct.
    If the circuit does not light up, modify it so
    that it does light the bulb.
  • Draw the circuit with the lit bulb in the space
    provided.
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