When did telephone operators become obsolete? The tools to make them unnecessary were invented in 1888, but telephone operators kept working, in one form or another, well into the late 20th century – and the job has still not completely disappeared. Alexander Graham Bell is usually named as the inventor of the telephone, but he […]
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How does a high-speed camera work? This might sound rather obvious, but a high-speed camera works by taking a lot of images very very quickly. High-speed cameras don’t just take more frames per second; they also give each frame a much shorter exposure time, so fast things aren’t blurred. There are obviously different standards, but
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How does a teleprompter work? A teleprompter works by projecting a script onto a mirrored glass panel. This allows the speaker to read the script and maintain eye contact with a camera or an audience, and it prevents the camera or audience from being able to see the script. A teleprompter works because light always
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What is a geothermal heat pump? A geothermal heat pump is a way of heating and cooling buildings by exchanging their heat with the ground. Natural objects obviously gain and lose heat depending on the amount of sunlight, what they are made of, the weather, where they are, and a whole host of other conditions.
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What is the difference between disc brakes and drum brakes? The main difference between disc brakes and drum brakes is their size and their position on the wheel. They both have advantages and disadvantages. All cars obviously have brakes, and they work on a hydraulic system. The brake lines are filled with a brake fluid
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How does an X-ray machine make an image？ An X-ray makes an image because some parts of the body absorb X-ray radiation and some parts of the body don’t. Bones absorb the majority of it and appear white. X-rays are a type of electromagnetic radiation with a wavelength between 10 nanometers and 10 picometers. There
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How does a speed camera work? Older types of speed cameras work out the time it takes for a car to travel between two known points. Modern speed cameras look at the wave length of radio waves or how long it takes light to return to the sensor. The old type of speed camera are
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Why do ships have a bulbous bow? Many ships have a bulbous bow to create a wave that helps reduce drag, which increases fuel efficiency. Any object that is moving, unless it is in a vacuum, is subject to forces that act upon it. These can be friction with the ground or surface, and wind
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What is fracking? Fracking is a method to get natural gas and oil out of shale rocks by fracturing them. Humans have used oil and natural gas for thousands of years, but we only really began using it on a large scale from the middle of the 19th century. It was the Industrial Revolution that
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How does a watch keep time? Modern watches use a quartz movement to keep time, but mechanical watches use a wound spring. Modern watches are probably easier to understand, so let’s look at those first. They work on the principle of piezoelectricity, which is a property that the mineral quartz possesses. The piezoelectric effect is
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