5.6 (B) demonstrate that the flow of electricity in circuits requires a complete path through which an electric current can pass and can produce light, heat, and sound

Vocabulary A circuit is a closed path through which electricity travels. The flow of electric charges through a circuit is an electric current. Material that allows energy to travel through it easily or quickly is a conductor. An electromagnet is made by passing an electric current through a wire that is wrapped around a metal object.

Electrical Energy Electricity can be converted (or transformed) into other forms of energy. For example: heat, light, sound and magnetic force. A circuits have an energy source, something that uses energy, wires for the energy to flow through and a switch to interrupt the flow of energy.

Heat and Light An electric current travels along a wire from a battery, through a switch to a bulb or other device that uses the energy, and finally back to the battery. If a bulb is left out of the loop or circuit, it will not receive the energy from the battery and will therefore, not light up.

Sound Electrical energy can be transformed into sound energy. A speaker is the device that uses the energy to vibrate. Vibrations create sound waves which your brain interprets as sound.

Electromagnet A speaker and motors work by using an electromagnet. It is made of wire coiled around an iron core like an iron nail. The wire is connected to a battery or other energy source. The current flows through the wire. This charges the iron nail making it magnetic. The electromagnet only works when the circuit is complete.

Sample Questions

Which simple circuit is complete? B. A. C. D.

Correct Answer Choice: The circuit is made from the bulb threads to the negative charge then through the battery to the positive charge and back to the bulb base.

Incorrect Answer Choices: The wire is not connected to the negative charge. A. The wire is not connected to the thread of the bulbs. B. The wire is not connected to the negative charge. D.

A student made this electrical circuit. However, the light bulb does not light up. What should the student do first to try to make the circuit work? Replace the bulb. Close the switch. Charge the battery. D. Open the switch.

Closing the switch will complete the circuit. Correct Answer Choice: B. Close the switch. Closing the switch will complete the circuit.

Incorrect Answer Choices: Replace the bulb is incorrect because the student cannot check to see if the bulb is burned out unless they close the circuit to test it. Charge the battery is incorrect because the student cannot check to see if the battery is charged unless they close the circuit to test it. Open the switch is incorrect because the switch is already open.

Which circuit will make a sound? B. A. C. D.

The circuit is complete. Correct Answer Choice: D. The circuit is complete.

Incorrect Answer Choices: The wire only connects the negative charge to the bell. A. The circuit is open. B. The bell is not connected to the positive charge. C.

Which of the following is NOT a conductor of electricity? Rubber Copper Silver Iron

Energy does not travel easily or quickly through the material. Correct Answer Choice: A. Rubber Energy does not travel easily or quickly through the material.

Incorrect Answer Choices: B. Copper is incorrect because energy does travel easily or quickly through the material. Silver D. Iron is incorrect because energy does travel easily or quickly through the material.

Which of the following variables will NOT create a stronger electromagnetic pull? Increase the number of coils. Use higher voltage battery. Use a copper wire. D. Use an aluminum wire.

Aluminum is not a good conductor of electricity. Correct Answer Choice: D. Use an aluminum wire. Aluminum is not a good conductor of electricity.

Incorrect Answer Choices: Increase the number of coils is incorrect because the number of coils around the iron nail will increase the magnetic pull. Use higher voltage battery is incorrect because the higher the volts a battery has, the stronger the magnetic pull. C. Use a copper wire is incorrect because copper is a good conductor of electricity.

Illustration Sources Electromagnet http://www.sciencetech.technomuses.ca/english/schoolzone/activities_scie1.cfm Bell http://office.microsoft.com/clipart Background http://office.microsoft.com/clipart