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How do sunglasses filter ultraviolet rays?

A special clear coating is applied to the lenses, either on the front or back of the lens, or sometimes both sides. It’s a transparent coating and can be applied to any colour of lens including clear. The UV-filtering effect, however, is more complex. UV-filtering lenses are coated with special chemicals that allow light to pass through them, but reflect …

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How do sensor doors work?

Sensor doors use motion sensors or presence sensors. The first are used to activate the door when it detects a moving object, such as a pedestrian or shopping cart. Motion sensors can distinguish between objects moving toward the door or away from it. They use microwave technology, and utilize the Doppler Effect principle. The sensors emit a high frequency microwave …

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How do Satellites Stay Up?

Ten, nine, eight, seven… zero – lift off. These words sound like music to an astronomer’s ears. As the countdown progresses, the rocket’s engines fire and give it the required push to tear through the atmosphere and escape the earth’s gravitation. These rockets take astronauts and artificial or man-made satellites into space. The satellites are used for communication, weather monitoring …

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How do geologists help us?

All the sciences, mathematics, physics, chemistry, and biology, are playing an increasingly important role in our way of life, as the years pass and we become more dependent upon the products of science and technology. Geology, too, has a vital part to play in living today, apart from its value in furthering our understanding of the way in which our …

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