Applied Science - Technology (3B)
Post Lab 

   
OBJECTIVES:
  • Evaluating electrical safety.
  • Comparing safe and unsafe electrical wire.

VOCABULARY:

  • electricity
  • insulation
  • safety
MATERIALS:

Students learn how to be "safe" when handling electricity.

BACKGROUND:

Electricity is used in our houses in many ways. We can use it for cooking, cleaning, cooling, freezing, heating, lighting, and entertaining. It helps make living and working around the home, school, or at work easy, safe, and fun. Electricity must be used properly, because it is also very powerful and can cause injury or fire.  We use electricity so much in urban area, that we sometimes forget it is there.

Students need to know that wires are not safe without insulation around the wires. Wires are insulated because they become hot and the coating prevents any fires from occurring.

Improper wiring can sometimes show warning signs like light will dim or flicker; motors change speed when an appliances goes on; circuit breakers trip or fuses blow frequently; heat-producing appliances are slow to warm; picture on the TV screen "shrinks": and you donít have enough outlets for all the appliances that need electricity.

There are also many other dangers that can prevent the flow of electricity to the city.  Large trees under utility poles can cause a disruption when a branch comes in contact with the electrical wires.  

Many times your local utility company may have informational brochures which can help you teach this lesson for your particular area.

PROCEDURE:
  1. Read "Night without Light,"  a story about a disruption of electricity due to a large tree.  
  2. Ask students if anyone has experienced such a "black out," due to a tree, lightning, car accident, or any other event that might make the light go out. 
  3. Use the worksheet and have students decide whether or not the situation shown is safe or not. Fill in the blanks on the chart
      
  4. ANSWERS
  1. If the child puts a tool into the socket, they will get 110 volts through their body. It is enough to kill someone.
  2. This is not immediately dangerous, but if there is a spark or a hot wire, the kit might burn causing problems. Never climb an electric pole. Call the utility company and they will inform you what to do.
  3.  If all the wiring is enclosed, nothing should happen. However, a broken wire could cause a shock.
  4. A broken wire is very dangerous. It can cause sparks which can cause a fire.

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