Topic – Light Technology

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Light Technology

The Sun was the first light source used by people. Later in history, people started to burn fuels to make light. First they burned animal fat in hollow objects. Over time, people designed new containers for burning fats. They added wicks to make the fire in the lamps burn more evenly. They started to use other fuels such as olive oil, beeswax, fish oil, whale oil, and nut oils. In the 1700s and 1800s, new lamps were designed. These used fuels that came from the ground, such as kerosene and coal. But the world was still a dark place for many people. Good fuels and lamps were expensive. Gas street lamps lit up only the area around each lamp.

Light Bulbs Today

Today most lighting depends on electricity. These are some different light sources used in homes, schools, and stores.

Incandescent: Inside these light bulbs is a thin wire that is heated by electricity. When the wire gets very hot, it gives off a visible light. It also gives off a lot of wasted heat. Incandescent bulbs do not last very long. They also use a lot of electricity to produce a bright light. These bulbs are not expensive.

Halogen: Halogen light bulbs work in the same way as incandescent bulbs. A wire inside the bulb is heated to produce light. The light from halogen bulbs is much brighter than the light from incandescent bulbs. Halogen bulbs also last longer, but they are more expensive. They also get very hot. They give off a lot of wasted heat.

Fluorescent: These are tubes filled with gas. Some bulbs are long, straight tubes, and others are spiral tubes. When electricity passes through the tubes, ultraviolet light is produced. This ultraviolet light causes other chemicals in the bulb to give off visible light. Fluorescent bulbs are more expensive than incandescent bulbs, but they use less electricity. They also give off much less heat.

Light-emitting Diode (LED): These are very different from other lights because they have a special material inside. The material produces light when electricity passes through the bulb. Different colours of light can be produced with different materials. LED lights last a very long time. They use very little electricity and do not get hot. LED lights are very expensive.

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