C. Matter and Energy · Electrical Phenomena, Energy, and Devices

Making Electricity: Energy Into Electrical Energy

C2.4 A1.5 A3.1About 45 minutes

Learning goals

I can explain how a generator uses motion to make electrical energy.
I can describe how hydroelectric, wind, nuclear and natural gas power stations transform energy into electrical energy.
I can describe how solar cells and batteries make electrical energy without a generator.
I can write an energy chain for a technology that makes electricity.

Words to know

generator
A machine that changes motion energy into electrical energy, using magnets and coils of wire.

turbine
A wheel with blades that spins when water, wind or steam pushes on it. It turns the generator.

hydroelectricity
Electricity made from moving water. Many people in Ontario call electricity "hydro".

solar cell
A device that changes light energy directly into electrical energy. Many solar cells together make a solar panel.

energy transformation
A change of energy from one form to another.

power grid
The network of power stations, power lines and equipment that carries electricity to homes and businesses.

Where does it come from?

When you plug in a charger, electricity is there, instantly. But it didn't start in the wall. It may have travelled hundreds of kilometres along power lines from a dam on a river, a nuclear station on a lake, or a wind farm in a field.

Electricity is not found lying around, ready to use. It has to be made by transforming another form of energy into electrical energy.

Tall white wind turbines with three blades standing in green farm fields, with power lines in front. — Wind turbines transform the kinetic energy of moving air into electrical energy, which travels to homes along power lines. AI-generated image

Remember from Grade 5

In Grade 5 you learned the forms of energy (kinetic, potential, chemical, thermal, electrical, light, sound and nuclear) and wrote energy chains that show energy changing from one form to another. You also learned that a hydroelectric dam uses water held high behind the dam to spin turbines, and you sorted renewable and non-renewable energy sources. Now you'll look more closely at how each technology makes electrical energy.

The generator: motion → electricity

Most of the world's electricity is made by generators. A generator has magnets and coils of copper wire. When a magnet and a coil of wire move past each other, an electric current flows in the wire. So a generator changes motion (kinetic) energy into electrical energy.

Something has to keep the generator spinning. In a power station, that's a turbine: a big wheel with blades. Water, wind or steam pushes on the blades and spins the turbine, and the turbine spins the generator.

How most power stations work: something moving pushes the turbine's blades, the turbine spins the generator, and the generator makes electrical energy.

Technology	How it works	Energy chain
Hydroelectric station	Water stored high behind a dam (or at a waterfall like Niagara Falls) flows down and spins turbines.	Potential (water held high) → kinetic (falling water) → kinetic (turbine) → electrical
Wind turbine	Wind pushes the giant blades, which spin a generator in the top of the tower.	Kinetic (moving air) → kinetic (blades) → electrical
Nuclear station	Splitting uranium atoms releases heat. The heat boils water into steam, and the steam spins turbines.	Nuclear → thermal → kinetic (steam and turbine) → electrical
Natural gas station	Burning natural gas releases heat. The hot gases or steam spin turbines.	Chemical → thermal → kinetic → electrical
Biomass station	Burning wood waste or other plant material heats water into steam to spin turbines.	Chemical → thermal → kinetic → electrical
Solar panel	Light hits solar cells and makes current flow directly. No moving parts, no turbine.	Light → electrical
Battery	Chemicals inside react and push current out of the terminals.	Chemical → electrical
Hand-crank flashlight or bike dynamo light	You turn a crank or pedal, which spins a tiny generator.	Chemical (your food) → kinetic (your muscles) → electrical

Technologies that transform other forms of energy into electrical energy.

Electricity in Ontario and Canada

In Ontario, about half of the electricity comes from nuclear stations, such as Bruce and Darlington. Another big share comes from hydroelectric stations, like the ones at Niagara Falls. The rest comes from natural gas, wind, solar and biomass.
Across Canada, more than half of all electricity comes from hydroelectricity. Provinces such as Quebec, Manitoba and British Columbia get most of their electricity from it, while Alberta and Saskatchewan use more fossil fuels.
Power stations send electricity along the power grid: high-voltage transmission lines on tall towers, then smaller lines on poles or underground, to homes and businesses.
Some remote communities, including many First Nations and Inuit communities in the North, are not connected to a grid and use diesel generators, which burn fuel to spin a generator.

The power grid, simplified and not to scale. Electricity travels from a power station along high-voltage lines on tall towers, then along smaller lines on poles (or underground) to homes and businesses.

Worked example

Let's write an energy chain for a nuclear station

Write an energy chain for a nuclear power station, from the uranium to the lights in your home.

Start with the energy stored in the uranium atoms: nuclear energy.
Splitting the atoms releases heat: thermal energy.
The heat boils water into steam. The steam rushes out and spins the turbine and generator: kinetic energy.
The generator makes electrical energy, which travels along the power lines.
In your home, a bulb changes it into light energy (and a little heat).

Nuclear → thermal → kinetic → electrical → light (and heat).

Just for fun

Someone asked a wind turbine if it liked making electricity.

It said, "Are you kidding? I'm a big fan!"

Hands-on activity

Model a turbine and test a solar cell

Part 1: Pinwheel turbine. You need: a square of paper (15 cm × 15 cm), scissors, a pencil with an eraser, and a pushpin.

With a grown-up, cut from each corner about two-thirds of the way toward the centre.
Fold every other point into the centre and pin them all to the pencil's eraser with the pushpin. Wiggle it so it spins freely.
Make it spin two ways: blow on it, first softly and then hard (wind), and hold it at an angle under a slow trickle of water from a tap over the sink (hydro). Which made it spin fastest? Did harder blowing make it spin faster?
Write an energy chain for each one. Remember that in a real power station, the spinning turbine would turn a generator.

Part 2: Solar cell test. You need: a solar-powered calculator (it has a dark strip of solar cells near the top).

In a bright room, type a number. Now cover the solar strip completely with your thumb or a piece of card. What happens to the display after a few seconds?
Try it in dim light. Write the energy chain: light → electrical (which runs the calculator and makes the numbers appear on the display).

Note: some calculators also have a backup battery, so they keep working when covered. If yours does, explain why!

Share it (A1.5): make a one-page poster showing three ways to make electrical energy, each with an energy chain.

Safety: scissors and pushpins need care; a grown-up should help, and keep the pushpin away from young children. Keep the water test away from plugged-in devices.

Jobs in electricity generation (A3.1)

Many people work to make electricity: wind turbine technicians climb towers to repair turbines; power station operators watch over hydro, nuclear and gas stations; millwrights (a skilled trade) maintain turbines and generators; and solar installers put panels on roofs.

Your turn

What does a generator do?

What is the job of a turbine in a power station?

Write the energy chain for a wind turbine.

How is a solar panel different from most other ways of making electricity?

What energy transformation happens in a battery?

Where does about half of Ontario's electricity come from?

More practice: warm-up

What pushes the turbine in a hydroelectric station?

What pushes the turbine in a nuclear station?

What fuel is burned in a natural gas station?

What two main parts does a generator have?

Many people in Ontario call electricity by what nickname?

More practice: on your own

Write the energy chain for a natural gas power station.

Nuclear and natural gas stations use very different fuels. What do they have in common in the way they make electricity?

Write the energy chain for a hand-crank flashlight, starting with the food you ate.

Why do many remote communities in northern Canada use diesel generators?

A solar panel on a roof makes electricity on a sunny day but almost none at night. Explain.

Challenge

An electric car slows down using "regenerative braking": the turning wheels spin its motor, which then works as a generator. Write the energy chain, and explain why this is useful.

Compare a hydroelectric station and a wind turbine. Give one similarity and one difference in how they make electricity.

Your pinwheel spun fastest when you blew hard on it. In a real wind turbine, why would a windier place make more electricity?

Check your understanding

Quiz

A generator changes...

Which technology makes electricity without a turbine or generator?

In a nuclear power station, the heat from splitting atoms is used to...

What is the energy chain for a battery-powered flashlight?

About half of Ontario's electricity comes from...

What spins the turbine in a hydroelectric station?

For parents and teachers

Big idea (C2.4): describe how technologies transform various forms of energy into electrical energy: generators driven by turbines (hydro, wind, nuclear, natural gas, biomass), solar cells (light → electrical) and batteries (chemical → electrical). Making a poster communicates findings (A1.5), and the careers tip links to occupations and skilled trades (A3.1).

How to help: look for power lines, transformers and wind turbines on drives. Ask, "How was the electricity in that line made?" If you have a solar calculator, solar garden lights or a hand-crank flashlight, use them as examples.

Common difficulties:

Thinking power stations "store" electricity. They transform energy into electricity as it's needed.
Missing the middle steps. For nuclear and gas, the chain includes thermal → kinetic (steam spinning turbines).
Thinking solar panels need a turbine. Solar cells have no moving parts.

Facts used: Ontario's mix (about half nuclear, with a large hydroelectric share) and Canada's (more than half hydroelectric) change a little from year to year.

Safety: help with scissors and pushpins; never let children approach power stations, transformers or transmission towers.