Electricity

Free online electricity lessons for elementary school,  middle school and high school.

 

The electric current

Dangers of electricity

1) The human body and its conductivity

The human body is a bad conductor (he would give a negative result with the conductivity test) but it is not totally insulated and can still be traversed by an electric current.

2) Dangers of the current depends on the voltage

The electric current is higher if the voltage is high.
- It is considered that in general 24 V is the voltage security: below this voltage we do not feel dangerous effects of electric current.
- Above 70 V there is a risk of death if contact is made with wet hands.

3) Electric shock and its effects

When a human body is traversed by an electric current, we say it suffers an electric shock.
An electric current may also cause an electrocution if the result is death.Electric shock can cause effects varying from simple tingling to respiratory paralysis, cardiac arrest, burns on the skin or internal organs, as well as involuntary muscle contractions.

4) Essential precautions

To prevent electric shock or electrocution it is necessary to take some essential precautions:
- Avoid handling electrical appliances in the presence of water.
- Do not strip electric wires.
- Remember to turn off power before changing a lamp.
- Do not push objects into electrical outlets and make them inaccessible to young children.
- Do not open any electrical appliance in use.

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