The particular type of semiconductor in an LED reacts when an electric current is passed through it by a process called electrolumincescence and this gives out lots of light, but not very much heat. The way that LED lights work is not actually very different to the way incandescent lights work.īut instead of heating up a wire to produce the white light, an LED light has a special material inside it called a “semiconductor” to produce the light. LEDs can also last a very long time, compared to other lights.Īn LED light, with labels. This is because they use much less energy – about one sixth – to make the same amount of light, since they don’t really get hot. In modern houses, schools and workplaces, the incandescent light has mostly been replaced with LED lights. The amount is usually written on the side of the light bulb for example 20 watts, 40 watts and so on.
The more energy used by the incandescent light, the brighter it will be. But when it reaches the filament, with its very thin wire, the electricity has to force its way through, using up a lot of energy which makes the filament very hot, and very bright. When the light bulb is connected to a source of electricity, the electricity can easily travel along the thick wires to the light bulb. But they also make a lot of heat – in fact, it’s only by getting very hot that they can light up at all – and this is seen as being wasteful of energy. These types of light bulbs are now mostly used in vehicles and low cost pocket torches because they are cheap and reliable. Tungsten is used in light bulbs because it has a really high melting point (over 3,000☌), which is much higher than the temperature needed to give a nearly white light (2,000☌). If you have a question you’d like an expert to answer, send it to We won’t be able to answer every question, but we’ll do our very best. Curious Kids is a series by The Conversation, which gives children the chance to have their questions about the world answered by experts.
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