Changing Electrical Energy Lesson 4 Changing Electrical Energy

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Changing Electrical Energy Lesson 4

Changing Electrical Energy Lesson 4

Changing Electrical Energy Electrical devices change electric energy into a form of energy we

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.

 Other useful forms of energy include heat energy, sound energy, and energy of

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.

What form of energy is produced? Heat

What form of energy is produced? Heat

What form of energy is produced? Motion

What form of energy is produced? Motion

What form of energy is produced? Sound

What form of energy is produced? Sound

What form of energy is produced? Motion Heat Sound

What form of energy is produced? Motion Heat Sound

Electric Motor An Electric Motor is a device that converts electricity into movement by

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.

Electric Heater An Electric Heater is a device that converts electricity into movement. All

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.

Sound is generated in speakers by the use of electromagnets which are moved by

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.

What is the Source? Electric energy comes from different sources. The source in an

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.

What is the Source? In a flashlight, the electric energy converts to light energy.

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.

For the diagram to the right, add the following labels a)Chemical energy electric energy

For the diagram to the right, add the following labels a)Chemical energy electric energy b)Electric energy light energy

Circuit Safety It is important to know how to build and use a circuit

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.

Lab-Find out why a badly connected circuit is an electrical hazard. Safety precaution Do

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. 2. Clean up your work area and put away all equipment after this activity. 1.

Procedure 1. Fold the aluminum foil so that it touches both terminals of the

Procedure 1. Fold the aluminum foil so that it touches both terminals of the battery. 2. Hold the foil in place for 5 seconds. Observe what happens. Then remove the foil.

What did you find out? Is the circuit open or closed? Open / Closed

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?

Short Circuit When you connected the two battery terminals with foil, you created a

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.

Circuit A. This circuit Circuit B. In this circuit, the is safe to work

Circuit A. This circuit Circuit B. In this circuit, the is safe to work with. insulation around the wire is damaged where the wires cross. This is a dangerous short circuit.

 Why is circuit B unsafe? Why wouldn’t the bulb light up if this

Why is circuit B unsafe? Why wouldn’t the bulb light up if this circuit was created?

Building Circuit Safety Comes first ◦ Check all your equipment and replace damaged equipment.

Building Circuit 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.

Connect loads in order Connect one end of a wire to the positive terminal

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.

Face all batteries the same way If you are connecting batteries together, always connect

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.

Keep Switch off. Always keep the switch in the “off” position until the circuit

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.

Testing Circuits Imagine you have just purchased a gaming system. You connect all of

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.

Checklist A circuit checklist is a set of three main questions. 1. Is the

Checklist A circuit checklist is a set of three main questions. 1. Is the circuit complete? Check to make sure that your circuit has a source, a useful load, and conductors. 2. Is the switch closed? Check to make sure that the switch is in the “on” position. 3. 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.

Look at the circuit diagrams below. Predict whether or not you think the bulb

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.