Bright ideas about electricity

Primary science content covered

 * S7-8:24


 * Understand the science behind basic electricity


 * Learn how to build a simple circuit
 * Teach the importance of saving electricity to help the environment

Each student or group will need:

 * One toilet paper roll
 * Five inch piece of insulated copper wiring


 * Two D batteries
 * One 1.5 volt light bulb


 * A roll of electrical tape

Handouts
[[Media:Build Your Own Flashlight Handout.pdf‎| A student quiz on the concepts covered in this activity]]

Description of activity
This activity requires a few materials to make your own flashlight. In order for your flashlight to work properly, it's important to learn how electricity works and connect the pieces of your flashlight properly. When you understand how the circuit works, your flashlight will shine bright!

Lesson plan
Class: 7th grade

Duration: 30 minutes

Key Vocabulary:


 * Atom: Basic unit of matter consisting of neutrons, protons and electrons


 * Electron: Negatively charged particle


 * Electrical current: Flow of electrical charges


 * Conductor: A material through which electrical charges can flow


 * Insulator: A material which offers large resistance to the flow of electric current


 * Closed circuit: creating a closed loop for electrons to flow through

Engage the class in this topic by asking for reasons why electricity is important and what it is used for.

Explain who Thomas Edison was: the inventor of electricity, and give a brief background of his life and accomplishments


 * Thomas Alva Edison lived from 1847-1941. He was always very interested in science, even from a young age, and tried to make a new invention every 10 days!  In his lifetime, he patented 1,100 inventions.  Some of his most famous works were:  the phonograph, the movie camera and the stock ticker.  The most important however, was electricity!

Basics: How to make a simple circuit (specifically a flashlight)


 * There are 3 main elements in a simple circuit; source of electricity (battery), path or conductor where electricity can flow (wire) and an electrical resistor (bulb) which needs electricity to work.


 * There is a flow of electricity from high potential at the positive terminal through the bulb then back to the negative terminal in a continuous flow.


 * Opposite charges attract and since electrons are negatively charged, they always move in the positive direction because they are more attracted to positively charged atom. The electron movement between atoms is what makes a current of electricity possible.


 * The batteries create free electrons, when the circuit connects the positive and negative terminals of the battery the electrons at the negative end move toward the positive end. This is called an electrical current.


 * When building your flashlight to conduct electricity, one of the most important things to remember is to have a closed circuit. When electrons are shared between atoms, they can't jump through the air so they must create a bridge, called a circuit.  If the circuit is open, the electrons can't travel any further and the electrical current stops (Fig. 2)


 * When the copper wire is connected to both the battery and light bulb, this creates a closed circuit. The electrons will be able to travel along this circuit, from negative to positive charges, generating electricity.


 * When the copper wire is not connected to the battery and/or bulb the electrons will not travel along the circuit and the bulb will not light up.


 * In order for the electrons to move to create electricity, they need a conductor like a wire. A conductor is something in which electrons can move through easily. Some materials are better conductors than others.  Good conductors are made up of matter that holds their electrons loosely.  They are therefore able to share their electrons more easily with other atoms.  For example, Styrofoam is a poor conductor, while water and most metals are excellent conductors.


 * Ask the students if they have ever touched a door knob and gotten a shock? Explain this is because human beings are good conductors of electricity being mostly made up of water. The electrons from our body are being easily shared with metal door handle.


 * The light bulb changes the electrical energy into light!



'''Step by Step Procedure of How to Build Your Own Flashlight!: '''
 * 1)  Tape the copper wire to the negative end of one of the D batteries (Fig. 3)


 * 1)  Tape the bottom of the toilet paper roll so no light will shine through (Fig. 4)


 * 1)  Stack the two D batteries together and tape around the edges to secure them together (Fig. 5)


 * 1)  Place this unit in the toilet paper roll.  The side of the unit where wire is taped to the battery, should be placed on the bottom of the toilet paper roll.  The wire should run up the side, inside the roll, and stick out the top (Fig. 6)


 * 1)  Tape the light bulb to the top of the battery (Fig. 7)


 * 1)  Touch the wire to the silver part of the bulb.  If everything is correct, the light bulb should light up!  If it does not, look at the potential pitfalls section to find the error (Fig. 8)

If you have followed the instructions and your flashlight is not working, go through this checklist of things that might be wrong:

 * 1) A working battery


 * 1) Batteries are in a position of opposite charges touching


 * 1) A working lightbulb.

Always have an adult supervising this activity and be particularly cautious of the following:

 * If your flashlight is generating a lot of electricity for long periods of time, the flashlight can emit a lot of heat and become very hot to touch.

Literature connections

 * Hands-on Experiments Physical Science- Gravity, Magnetism and Electricity. REM 6525. Scottsdale, AZ: Remedia Publications, 2007.


 * Gosnell, Kathee. Electricity Thematic Unit. Wilmington: Teacher Created Resources, 2004.


 * Jackson, Herbert W., Dale Temple, and Brian Kelly. Introduction to Electric Circuits. 8th ed. New York: Oxford UP, 2008.


 * Spencer, James N., George M. Bodner, and Lyman H. Rickard. Chemistry Structure and Dynamics. Vol. 4. New York: John Wiley & Sons, 2008.

Connections to educational standards
S7-8:24

Students demonstrate their understanding of Electrical Energy by…

electrical energy into heat, light, and sound, leaving the system but not destroyed.
 * Building an electric circuit and explaining the transfer of

Science Concepts:

energy when heat, light, and sound are produced. The electrical energy is spread out yet still conserved.
 * Electric circuits provide a means of transferring electrical

Next steps
Conservation of energy

Teachers should talk to their students about ways they can help conserve electricity such as turning off the lights as they leave the room and encouraging their parents to use more energy efficient light bulbs. Ask them if they can think of any other ways they can help! We need to conserve energy because of the dangers it presents to our environment. Similar to using the battery to power our flashlight, there are other larger sources we use every day to produce the world's electricity. The major source is through the burning of fossil fuels. Examples of fossil fuels are coal, oil, and natural gas. When burning these fossil fuels to produce energy, this creates an excess of greenhouse gases. Our earth acts as a greenhouse where the earth's surface absorbs the incoming rays of the sun in order to warm the earth. The earth then reradiates some these rays but they do not all escape back into space because the greenhouse gases prevent them from leaving. This helps keep the earth warm! The main greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbons. When burning fuel for energy to power electricity, we emit more of these greenhouse gases into the atmosphere. The abundance of these greenhouse gases prevents much of the earth's absorbed heat from escaping and this ultimately causes an increase in temperature of the earth! This has come to be known as global warming. This can be dangerous by throwing off the balance of the earth's ecosystem.

Citations and links

 * Hands-on Experiments Physical Science- Gravity, Magnetism and Electricity. REM 6525. Scottsdale, AZ: Remedia Publications, 2007.


 * Gosnell, Kathee. Electricity Thematic Unit. Wilmington: Teacher Created Resources, 2004.

Vermont Science Standards
 * Spencer, James N., George M. Bodner, and Lyman H. Rickard. Chemistry Structure and Dynamics. Vol. 4. New York: John Wiley & Sons, 2008.

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