๐ Inventions and machines ๐ง Machines and tools
Electric light
๐ In short
Electric light is light we get from electricity, in the lamps that light our homes, streets and schools. Before it spread about a hundred years ago, people lit the night with candles and oil and gas lamps.
๐คฉ Did you know?
- Electricity heats a bulb's filament to more than 2500 degrees.
- An ordinary 100-watt bulb gives about 1750 lumens of light.
- An LED uses a small fraction of the electricity of an old bulb.
- A lamp's light is measured in a unit called the lumen.
๐ Find out more
๐ The incandescent bulb
An old light bulb has a very thin wire called a filament. When electricity flows through it, it gets so hot it glows. But it wastes most of the electricity as heat.
๐ The energy-saving bulb
Modern energy-saving bulbs like LEDs give strong light, use much less electricity, don't get very hot, and last for many years.
๐ก Colored lights
Cities have lots of colored lights in signs and traffic lights. Some are tubes with special gases that glow in different colors when electricity passes through them.
๐ฏ Save electricity
Switch off the light when you leave a room and use sunlight in the daytime, and you'll save electricity and protect the environment.
๐งฉ Test yourself
1 What happens to the filament when electricity flows through it?
2 Which lamp saves electricity?
3 Electricity heats a bulb's filament to more than ?? degrees.
4 Which picture shows โElectric lightโ?
๐ Discover more
๐ท Picture sources: Wikimedia Commons
- Hidalgo944 ยท CC BY-SA 4.0
