Electrical Safety World

Need to write a report about electricity? Or just want to know more about some aspect of electricity that's caught your interest? You've come to the right place. Simply click on the questions below, and you'll be on your way.

What is electricity?
How is electricity generated?
What is hydroelectric energy?
How does electricity travel?
How is electricity measured?
Do the words "shocked" and "electrocuted" mean the same thing?
Why can you sometimes see a spark if you can't see electricity?
When a circuit is open, do electrons go backwards, or do they just stop?
Why does electricity try to get to the ground, and what does it do when it gets there?
Why can a bird stand on a power line and not get shocked?
What is static electricity?
What is lightning?
How much energy is in a bolt of lightning?
Does lightning ever strike fish?
Who holds the world's record for most often to be hit by lightning?
Why didn't Benjamin Franklin get electrocuted when he tied a metal key to a kite string and flew the kite in a thunderstorm?
Why shouldn't I use a corded phone or electrical appliance during a thunderstorm?
How do batteries create electricity?
Why don't I get a shock when I touch a battery?
Do electric eels really create electricity?
How does a defibrillator work?
How does a lightbulb work?

What is electricity?
Electricity is a form of energy that starts with atoms. Atoms are too small to see, but they make up everything around us. An atom has three tiny parts: protons, neutrons, and electrons. The centre of the atom has at least one proton and one neutron. At least one electron travels around the centre of the atom at great speed. Electricity can be created by forcing electrons to flow from atom to atom.
How is electricity generated?
Most electricity used in New Zealand is produced at power stations. Various energy sources are used to turn turbines. The spinning turbine shafts turn electromagnets that are surrounded by heavy coils of copper wire inside generators. This creates a magnetic field, which causes the electrons in the copper wire to move from atom to atom.
What is hydroelectric energy?
Hydroelectric plants use the power of falling water to turn the turbines that help generate electricity. Water stored behind a dam is released and directed through special tubes to flow against the blades of turbines and make them turn. Hydropower provides about 60-70 percent of the electricity generated in New Zealand.

How does electricity travel?
Electricity leaves the power station and is sent over high-power transmission lines on pylons. The very strong electric current from a power station must travel long distances to get where it is needed. Electricity loses some of its strength (voltage) as it travels, so transformers, which boost or "step up" its power, must help it along.

When electricity gets closer to where it will be used, its voltage must be decreased. Different kinds of transformers at electricity supplier substations do this job, "stepping down" electricity's power. Electricity then travels on overhead or underground distribution wires to neighbourhoods. When the distribution wires reach a home or business, another transformer reduces the electricity down to just the right voltage to be used in appliances, lights, and other things that run on electricity.

A cable carries the electricity from the distribution wires to the house through a meter box. The meter measures how much electricity the people in the house use. From the meter box, wires run through the walls to power points and lights. The electricity is always waiting in the wires to be used.

Electricity travels in a circuit. When you switch on an appliance, you complete the circuit. Electricity flows along power lines to the power point, through the power cord into the appliance, then back through the cord to the power point and out to the power lines again.

Electricity travels fast (299,460 kilometres per second). If you travelled that fast, you could travel around the world eight times in the time it takes to turn on a light. And if you had a lamp on the moon wired to a switch in your bedroom, it would take only 1.26 seconds after you flipped the switch for electricity to light the lamp 384,560 kilometres away.
How is electricity measured?
Volts, amps, and watts measure electricity. Volts measure the "pressure" under which electricity flows. Amps measure the amount of electric current. Watts measure the amount of work done by a certain amount of current at a certain pressure or voltage.

To understand how they are related, think of water in a hose. Turning on the tap supplies the force, which is like the voltage. The amount of water moving through the hose is like the amperage. You would use lots of water that comes out really hard (like a lot of watts) to wash off a muddy car. You would use less water that comes out more slowly (like less watts) to fill a glass.

1 watt = 1 amp multiplied by 1 volt
1 amp = 1 watt divided by 1 volt
Do the words "shocked" and "electrocuted" mean the same thing?
No. Someone can be shocked by electricity and survive. But when we say someone has been electrocuted, it means they have been killed by electricity.
Why can you sometimes see a spark if you can't see electricity?
You can't see electricity when it is flowing through a circuit. But if electricity leaves the circuit—like when someone is shocked—you can see a spark. The spark isn't electricity itself. It is a flame that happens when the electricity travels through the air and burns up oxygen particles.
When a circuit is open, do electrons go backwards, or do they just stop?
Neither. In the wires of an electrical circuit, the electrons are always jiggling around. When a circuit is closed to run an appliance or a lightbulb, the electrons jiggle a lot and travel through the wire. When the circuit is open, all the electrons just jiggle where they are—kind of like running in place.
Why does electricity try to get to the ground, and what does it do when it gets there?
It's just the nature of electricity to move from an area of higher voltage to an area of lower voltage, if given a path to travel there. The ground is simply the lowest-voltage area around, so if you give electricity a path to the ground, it will take it, no questions asked. When electricity goes into the ground, the earth absorbs its energy.
Why can a bird stand on a power line and not get shocked?
It is easier for electricity to keep flowing through the power line than to go through the bird. But if a bird with large wings touches a power line and a tree or power pole at the same time, it provides electricity with a path to the ground, and could be shocked. And if a bird touches two wires at once, it will create a circuit—electricity will flow through the bird and likely electrocute it.
What is static electricity?
If you drag your feet across synthetic carpet on a dry day, electrons from the carpet get transferred to your body.
What is lightning?
Lightning is a large discharge of static electricity. During a thunderstorm, clouds build up a charge. When there is a big difference in charge between the cloud and its surroundings, the cloud discharges a lightning bolt.
How much energy is in a bolt of lightning?
One lightning strike can carry up to 30 million volts—as much electricity as 2.5 million car batteries.
Does lightning ever strike fish?
Yes, it does. Because water conducts electricity, when lightning strikes water it spreads out along the surface. Any fish near the surface of the water get electrocuted.
Who holds the world's record for most often to be hit by lightning?
According to the Guinness Book of Records, Roy G. Sullivan, a former U.S. park ranger, was struck by lightning seven times over the course of his 35-year career. Lightning has burned off his eyebrows, seared his shoulder, set his hair on fire, injured his ankle, and burned his belly and chest.
Why didn't Benjamin Franklin get electrocuted when he tied a metal key to a kite string and flew the kite in a thunderstorm?
Benjamin Franklin's famous key did give off an electric spark. But lucky for Franklin, the kite was just drawing small electrical charges from the air. If the kite had actually been struck by lightning, Franklin would have been killed.
Why shouldn't I use a corded phone or electrical appliance during a thunderstorm?
There is a very small chance that a lightning strike could surge through phone lines or through the wires of an electrical appliance. If you were to touch a phone or appliance at just that moment, you could be shocked.
How do batteries create electricity?
A chemical reaction within the battery forces electrons to move.
Why don't I get a shock when I touch a battery?
There is not enough voltage in a regular household battery to cause a shock. However, car batteries are powerful enough to shock so you should never tamper with them.
Do electric eels really create electricity?
Yes. An electric eel uses chemicals in its body to manufacture electricity. A large electric eel can produce a charge of up to 650 volts, which is more than five times the shocking power of a household power point.
How does a defibrillator work?
Inside the cells of the heart, tiny electrical currents fire in a steady rhythm. If that rhythm is disrupted due to disease or injury, a heart attack can occur. A defibrillator shocks every cell in the heart at the same time, so they all start up again in rhythm. It's like each cell is dancing to the same beat.
How does a lightbulb work?
The wire inside a lightbulb is called a filament. It is made of tungsten, a metal that stays solid at very high temperatures. Electricity flows through the tungsten filament, causing it to heat up and glow. The glow gives off light. Inside a lightbulb is a vacuum—in other words, all the air has been removed from inside the glass bulb. (If there were air inside, the wire would burn up.)