What are gravitational waves? Gravitational waves are ripples in spacetime that head through space like ripples on a pond, except in three dimensions. They travel at the speed of light, and they compress space as they pass. They are caused by violent events, such as when two black holes collide. Everything that has mass has […]
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How does Velcro work? Velcro consists of two pieces of tape. One side has hooks and the other side has loops. When you put them together, the hooks get caught in the loops and hold the two pieces of tape together. Velcro is a brand name, but it has become synonymous with the product, just
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How does a lava lamp work? There are two principles at work in a lava lamp. The first is how a substance can stay together when surrounded by water. The second is how heat affects the density of a material. The lava lamp that we know today was invented by a British accountant called Edward
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How can you 3D print metal? You can 3D print metal in the same way you can 3D print plastic. It has to be melted in some way, shaped, and then allowed to harden. Plastic 3D printing has been around for a while, and there are several different kinds. The cheapest and the most basic
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Why did the Industrial Revolution start in Britain? Nobody can say for sure why the Industrial Revolution started in Britain rather than somewhere else, but there are several likely theories. Britain had easily accessible resources, a large empire to provide resources and a market, a stable political system, an efficient agricultural industry, a respect for
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Why does metal feel colder than wood? Metal feels colder than wood because metal has a far higher thermal conductivity than wood does. There are two things we need to look at here: how metal conducts heat, and how our hands sense temperature. Heat is not actually a thing. Heat is a process. It is
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How does photosynthesis work? Photosynthesis works by taking water and carbon dioxide, then using energy from the sun to convert them into glucose through the chlorophyll in its chloroplasts. Without photosynthesis, it is safe to say that there wouldn’t be any life on Earth. Photosynthesis is the primary source of energy among living things on
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How does a thermal imaging camera work? A thermal imaging camera works by detecting infrared radiation and then processing it into an image that can be displayed on a screen. Everything on Earth can absorb heat or radiate heat. Mammals, such as us, create our own heat by burning the food we eat to make
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Why do black holes evaporate? Black holes evaporate because of something called Hawking radiation, which is where they lose energy when particles appear outside their event horizon. Nobody knows how many black holes there are in the universe because they are black, and they are very difficult to see. They can only really be seen
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What is Greek fire? It was a burning material that was invented as a weapon by the Byzantine Empire in the 7th century. We call it Greek fire, in English, but it was not really Greek. The Byzantine Empire was created when the Roman Empire split into Western and Eastern halves. The eastern half became
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