Electricity is everywhere
Think about your morning: an alarm wakes you, lights turn on, the fridge keeps milk cold, the toaster browns bread and your phone charges. Electrical energy makes modern life possible because it is easy to send along wires and easy to change into other forms.
Energy transformations
Electrical devices work by energy transformation, changing electricity into the form we need.
| Electricity becomes… | Devices |
|---|---|
| Light | LED bulbs, screens, streetlights |
| Heat (thermal energy) | Toasters, kettles, stoves, space heaters, clothes dryers |
| Motion (kinetic energy) | Fans, blenders, washing machines, electric cars, elevators |
| Sound | Speakers, headphones, doorbells |
| Chemical energy | Charging batteries |
| Electromagnetic waves | Microwave ovens, Wi-Fi routers, cell phones |
Most devices produce some heat as waste. That’s why your phone or laptop gets warm.
Uses in the home
Heating
A heating element is a coil of high-resistance wire, often made of nichrome. When current flows, the wire gets hot and glows red. Kettles, toasters, hair dryers and electric stoves all use heating elements.
Many Canadian homes use electric baseboard heaters or, increasingly, heat pumps, which move heat from outside air into the house instead of making it, using far less electricity.
Motion
An electric motor turns electricity into spinning motion using magnets and coils of wire. Motors are in fans, fridges (compressors), vacuum cleaners, power tools and electric vehicles.
Lighting
| Bulb | How it works | Efficiency |
|---|---|---|
| Incandescent | Heats a thin wire until it glows | Only about 5% becomes light |
| Fluorescent | Gas glows when electricity passes through it | Better |
| LED | A semiconductor gives off light directly | Best; uses about 75–90% less energy than incandescent |
Cooling
Refrigerators, freezers and air conditioners use electric motors to pump a special fluid that carries heat out of the inside.
Uses in communication and information
Electricity powers computers, smartphones, the internet, radio, television and satellites. Tiny electrical signals represent all the data we send and store.
Uses in medicine
| Device | What it does |
|---|---|
| X-ray machine | Uses high voltage to produce X-rays |
| MRI scanner | Uses powerful electromagnets |
| Pacemaker | Sends electrical pulses to keep the heart beating regularly |
| Defibrillator | Delivers a shock to restart a heart |
| ECG | Records the heart’s electrical activity |
Uses in industry and transport
- Electrolysis: electricity drives chemical reactions to make aluminum, chlorine and hydrogen, and to electroplate metals with thin coatings.
- Electric arc furnaces melt scrap steel for recycling.
- Transportation: subways, streetcars, electric buses and electric cars. Montreal’s métro and Vancouver’s SkyTrain run on electricity.
- Robots and automated machines build cars and sort packages.
Measuring electricity use
Power is measured in watts (W). Energy used is measured in kilowatt-hours (kWh).
energy (kWh) = power (kW) × time (h)
| Appliance | Power | Use for 1 hour |
|---|---|---|
| LED bulb | 10 W | 0.01 kWh |
| Laptop | 50 W | 0.05 kWh |
| TV | 100 W | 0.1 kWh |
| Microwave | 1000 W | 1 kWh |
| Clothes dryer | 3000 W | 3 kWh |
Your electricity bill charges for each kilowatt-hour. If electricity costs 12 cents per kWh, running a clothes dryer for an hour costs about 36 cents.
Using electricity wisely
- Switch off lights and devices when not in use.
- Use LED bulbs.
- Choose ENERGY STAR appliances.
- Dry clothes on a line when possible.
- Unplug chargers; many draw "phantom power" even when nothing is attached.
Saving electricity lowers costs and reduces pollution from power plants that burn fossil fuels.
Common mistakes
- Thinking all electricity is clean. It depends on how it’s generated.
- Thinking watts and kilowatt-hours are the same. Watts are power (rate); kWh are energy (amount).
Try it yourself
- List 10 electrical devices in your home and the energy transformation each makes.
- Find the wattage label on three appliances. Calculate how much energy each uses in a week.
- Do a home "energy audit": find three ways your family could save electricity.
Quick recap
- Electricity is easy to transmit and transform into other forms.
- Devices change electricity into light, heat, motion, sound and more.
- Heating elements, motors and LEDs are key technologies.
- Electricity is essential in communication, medicine, industry and transport.
- Energy use is measured in kilowatt-hours; saving it helps your wallet and the planet.