1. Electrical Safety
& Cells and Batteries

2. Fulgurites
Lightning can be dangerous because it discharges so much energy.
Lightning strikes can actually melt sand and rock when they hit the ground.

3. When lightning melts sand & rock…
It creates glass- lined tubes called fulgurites.

4. Electrical Safety
January 1998 eastern Ontario and Quebec were hit by a massive ice storm.
Any person coming into contact with a power line may create a path for electricity.
This path is sometimes called short circuit.

5. Without a complete circuit…
Electricity cannot flow.
If electricity can find another path, such as through a person’s body to the ground, then it will take that path.
Ice Storm

7. Dangers of Electrical Shock
Two important aspects of electricity: voltage & amperage.
High voltage is more dangerous than low voltage; V more likely to kill you than 10 V.
Even small voltages can kill if the shock carries a significant number of amps (rate of flow).

8. Amps more important than voltage:
When assessing the potential danger of electrical shock.
0.001 A passing through your body- likely would not feel it.
0.015 to A- painful shock & loss of muscle control.
Current as low as 0.1 A can be fatal.

9. Factors affecting electric shock:

10. Current does not flow easily:
Through insulators such as wood, rubber & air.
You might feel just a tingle if you touch an electrified fence on a dry day when you are wearing running shoes.
But, you could get a nasty shock if you touch the fence when you are barefoot in the rain.

12. Every plug-in device:
Sold in Canada must have a label listing what voltage it requires and the maximum current it uses.

13. The amperage rating does not have to be high for you to get a shock.
If there is a short circuit or if the insulation is damaged, you could get a shock from the electricity before it goes through the device.

15. Plugs, Fuses & Breakers
Grounded 3 prong plugs have an extra wire that connects the device to the ground wire of the building.
It provides another pathway for electricity, just in case there is a short circuit.
Electricity travels to the ground instead of through the user.

16. Fuses Interrupt a circuit when too much current is flowing through it.
Contain a thin piece of metal that is specially designed to melt if too much current passes through it.

17. Circuit Breakers
Have a special wire that heats up if there is too much current.
Hot wire triggers a spring mechanism that turns off the switch inside the circuit breaker.
As soon as problem is fixed/wire has cooled, the circuit breaker can be turned back on.

18. The danger of lightning
The current in a lightning strike can be as high as A, and they can kill.
People can survive lightning strikes when the full amount of current travels over only part or over the surface of their bodies.

19. The danger of lightning
Lightening is a huge amount of negative charge and tends to seek the highest point on the horizon to discharge.
Tall buildings are a natural target for lightening strikes, and so often add lightening rods to their peaks- lightening rods are connected to the ground with a wire; discharge is conducted harmlessly to the ground.