How do we make blood? Blood is made in our red bone marrow in a process called hematopoiesis. People have different quantities of blood depending on their size, but it is usually about 8% of a person’s body weight. 55% of the blood is made up of plasma, and the other 45% is a combination […]
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How does a jet engine work? A jet engine works by mixing fuel with compressed air and then burning it. The gas expands, shooting out of the back of the engine, which pushes the plane forwards. At first glance, it would be difficult to understand how a jet engine moves a plane along. We naturally
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Why did people start using wallpaper? People first started using wallpaper to insulate their houses, but only the rich could afford it. Later on, wallpaper became cheaper and people used it because they couldn’t afford tapestries to cover their walls. Wallpaper, along with paper itself, was invented in China. The earliest known wallpaper was used
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Do we still need weather balloons? Yes, weather balloons are still needed. Satellites can provide a lot of data, but they still cannot sample the atmosphere directly from inside it, and they are far more expensive. There are thousands of satellites in orbit around Earth at the moment, so it is easy to assume there
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Why do cats’ eyes glow in the dark? A cat’s eyes glow in the dark because they have a special reflective layer in their eyes called a tapetum lucidum. Cats aren’t the only animals whose eyes glow at night. The reason for this comes down to the way that we see and why we can’t
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Who was Lloyd in Lloyd’s of London? His name was Edward Lloyd, and he ran a coffee house in London in the late 17th and early 18th centuries. Lloyd’s of London is very famous, and the name often comes up with major disasters. However, Lloyd’s of London is not an insurance company. Rather, it is
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How can we stop future civilizations from digging up our nuclear waste? It is almost impossible to imagine that we might be able to stop future civilizations from digging up our nuclear waste, but there are some ideas that people have come up with. Nuclear power is an incredible way of producing electricity. There are
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What were prison ships? Prison ships were ships floated in the River Thames and other places around Britain in the 18th and 19th centuries to cope with overflowing prisons. Britain was not the only country to use prison ships, but it probably made greater use of them than other countries. In the late 18th century
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How do astronomers find exoplanets? Astronomers find exoplanets by measuring tiny changes in starlight, seeing if a star shifts position in the sky, measuring radial velocity, using gravitational microlensing, and sometimes looking at the planet itself. There are billions of stars in our Milky Way galaxy, and it is likely that a huge number of
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Why doesn’t moving water freeze? Moving water does freeze, but it takes a lot longer and the temperature has to be lower than for still water. This is because of turbulence and heat transfer. It is difficult to make ice in both moving water and standing water. Water does not change temperature quickly, because it
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