Lesson 2: Electrical Safety Ladders can become electrified if they come into contact with electric wires. Don't raise a ladder close to electric

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Neal McGee
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1 Lesson 2: Electrical Safety Ladders can become electrified if they come into contact with electric wires. Don't raise a ladder close to electric lines. Never touch hanging or broken wires. Don't trim trees or shrubs with hidden power lines nearby. Be sure cords on electrical tools are not burnt. Never break off the 3rd prong on a 3 prong extension cord Underground power lines can pose a hazard if struck by shovels. Check before digging! Never use outdoor electrical tools, such as drills, in rain or on wet surfaces Don't plug too many appliances into one outlet Never use electrical appliances in the shower or bath If there are small children in your house, use plastic safety caps on unused outlets Never insert a metal object in an outlet Never insert a metal object into an appliance without unplugging it first Never climb trees near power lines Do not pull on cords to unplug appliances. Hold the plug, not cord Do not touch or go near electrical equipment. Stay away from anything marked "Danger", "High Voltage" or "Keep Out" Check the wattage of all bulbs in lighting fixtures to make sure they are the correct size for the fixture.

2 Lesson 3: What is Electricity? Every living and non-living thing is made of atoms. Atoms are so small they cannot be seen, even with a microscope. The center of an atom is called the nucleus. The nucleus contains particles called protons and neutrons. Neutrons have no electrical charge. Protons have a positive charge. Orbiting the nucleus of an atom are electrons. Electrons orbit the nucleus the same way planets orbit the sun. Electrons have a negative charge. Usually, an atom has the same number of protons and electrons and has no electrical charge. This is called neutral. Some atoms can lose or gain electrons. When they lose electrons, they become positively charged. When they gain electrons, they become negatively charged. Objects can get a negative charge by picking up electrons from other objects. For example, when you scuff your feet on carpet, you are picking up electrons. Objects with opposite charges will attract each other. Objects with same charges will repel each other. Attract - drawn together; opposite charges attract Repel - force apart; like charges repel Electrons - Negatively charged Protons - Positively charged Neutrons - Neutral

3 Static Electricity- a form of electricity that is produced when materials are rubbed together. Static means staying in one place. This electricity stays on the objects until something happens to transfer it. It does not move like electricity travelling through wires. When we rub a balloon on our hair, we are creating static electricity because we are picking up electrons. This gives the balloon a negative charge. The electricity will stay on the balloon until the balloon touches something else and transfers the electrons. How are static and current electricity the same and different? Static and current electricity both produce electricity through two kinds of charges; positive and negative. The difference is that static electricity stays in one place (stationary), while current electricity moves along a path. current - electricity that moves through a circuit

4 Lesson 4:Making Electricity (batteries) Battery- a battery is a container that holds the chemicals that make electric energy All batteries work on the same principle - they have 2 electrodes and an electrolyte. Electrons will collect on one electrode while the other electrode loses electrons. Electrons will move from areas where there are more electrons to areas where there are fewer electrons. Electrode - the part of a battery where the current goes in or out of the battery Electrolyte - a substance in a battery that can conduct electricity In what ways are the lemon/potato battery like a regular battery? In what ways are they different? Both the lemon/potato battery and the regular battery produce electricity. Each battery runs on two pieces of metal in a liquid. The regular battery lasts longer because it is better insulated and more sophisticated.

The lemon/potato acts as the electrolyte and the copper and zinc are the electrodes.

5 How does a lemon/potato battery work? The lemon battery works much like a regular battery. Copper and zinc are placed in lemon/potato juice. The lemon/potato acts as the electrolyte and the copper and zinc are the electrodes. When the copper and zinc are placed in the lemon/potato juice, electrons flow creating electricity. The electrolyte helps break down the structure of the metals causing electrons to be released. Electrons will flow from the - to the +. The energy created comes from the movement of electrons.

Lesson 5: What can electricity travel through? conductor - an object or material that will allow an electric current to travel through it. Examples: metals; silver, copper, lead.

6 Lesson 5: What can electricity travel through? conductor - an object or material that will allow an electric current to travel through it. Examples: metals; silver, copper, lead. Silver is the best conductor. insulator - an object or a material that will not allow an electric current to travel through it. Examples: plastic, rubber, glass Why are wires covered in plastic or rubber? Plastic/rubber is an insulator. Electricity cannot travel through it. The electricity stays safely inside where it cannot harm anyone who touches it. Why is it important to have fuses or circuit breakers? Sometimes there may be too many electric devices operating at the same time. This can be dangerous, because the wires leading to one circuit could get hot enough to start a fire. If this happened the fuse would melt or the breaker would trip, causing the circuit to be incomplete. Therefore, electricity would no longer flow. Fuses and circuit breakers can help prevent fires.

electric current travels; current will not travel unless a circuit is complete and has no breaks.

7 fuse - a thin wire placed in a circuit to prevent too much electricity from travelling through the circuit. The fuse will melt and break the circuit if too much electricity is travelling through Lesson 6: Types of Circuits Circuit- the path through which an electric current travels; current will not travel unless a circuit is complete and has no breaks. Series Circuit: A circuit in which the current travels along a single path to two or more electric devices; the current travels through each part of the circuit. Ex: string of Christmas lights in which all lights go out if one bulb goes out. The blown bulb breaks the circuit.

*Symbols used for drawing circuits can be found on page 21 of your text Switch a device that controls the flow of electric current

8 Parallel Circuit: A circuit in which the current travels along two or more separate paths to different devices; the current travels through each part of the circuit at the same time. *Symbols used for drawing circuits can be found on page 21 of your text Switch a device that controls the flow of electric current through a circuit. In an open circuit, the switch will be open, causing a gap in the circuit so that electricity cannot flow. In a closed circuit, the switch will be closed and electricity will be able to flow.

9 What happens when you add another bulb to a circuit? - The bulbs will get dimmer because the same amount of power will need to provide energy to two bulbs instead of one. What happens when you remove a bulb from a series circuit with 2 or more bulbs? - The other bulbs will go out because the circuit now has a gap in it where that bulb used to be. It is now an open circuit, which electricity cannot flow through. What happens when you remove a bulb from a parallel circuit with 2 or more bulbs? - The other bulbs will stay lit. Removing a bulb will only break the circuit on that pathway. The other pathways are still closed and electricity can still travel to those bulbs.\ Electron flow - negative to positive Conventional flow - positive to negative

Understanding Electricity and Electrical Safety Teacher s Guide

Understanding Electricity and Electrical Safety Teacher s Guide Note to Instructor: The activities and experiments in this booklet build on each other to develop a student s understanding of electricity