Edita Bromova
Is there a black light?
To watch a movie, whether it's projected on a wall at home or on a big screen at the cinema, you need a movie projector that will project beams with information about the image. It will direct red beams to where the red is supposed to be and green beams to where the green is supposed to be. If the image is to be white, the projector will direct all the colours it has at its disposal. Putting all the colours together is what produces white.
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Edita Bromova
How fast do you have to run to turn into a black hole?
The term "black hole" was first used in 1967 by Frank Wheeler to describe a cosmic body, which until then had been called a "black star" or a "gravitationally completely collapsed body". It is a bizarre object that is so…
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Jaroslav Kores, Ph.D.
Why does water in a kettle bubble before it reaches the boiling point (90° +) and when the kettle turns off and the thermometer reads 100 °C, it no longer does?
Boiling is a special case of evaporation — its peculiarity is that it occurs at a specific temperature (the boiling point) and at this temperature, evaporation takes place throughout the entire volume of water (which are…
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Jaroslav Kores, Ph.D.
Does a permanent magnet have a permanent magnetic field? Can it be depleted?
Because electricity and magnetism are closely related (they are actually different manifestations of the same phenomenon), the magnetic properties of substances are related to electrons. Each electron is a (very small) m…
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