Why do cameras have mirrors? To flip the image so that we can see it the right way up through the viewfinder. There are two types of cameras: ones with mirrors and ones without. The cameras without mirrors are digital and they don’t need to physically rotate the image because they don’t have a viewfinder. […]
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How can an eagle see so far? Eagles can see about eight times farther than humans because the cones in their eyes are very small and tightly grouped together. There are 68 different species of eagle spread across the world. They are birds of prey that hunt by swooping down on their prey from high
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Why is lead poisonous? It settles in cells and interferes with many different enzymes, preventing the cells from working properly. Lead is a heavy metal that is very dense. It is also fairly soft. These days, a lot is known about lead poisoning, so lead is treated very carefully in factories and in devices that
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How do people predict the weather? These days, by using AI and supercomputers. People have tried to predict the weather for millennia. When most of the population were involved in the agricultural sector, knowing the weather was important. However, the day to day weather may have been less important than the seasonal weather. If there
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How long did it take for the sun to get hot? Approximately 10 million years for it to start burning. The sun is hot because of nuclear fusion, which is where hydrogen molecules are squashed together under great pressure to make a helium molecule. There is a difference in the atomic weight of the hydrogen
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When did oxygen appear on Earth? Oxygen appeared on Earth between 2.4 and 2.2 billion years ago. The air we breathe is not made up mostly of oxygen. It is 78.084% nitrogen, 20.934% oxygen, 0.934% argon, 0.035% carbon dioxide, and then a lot of other trace elements. Our bodies need the oxygen and the carbon
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What is a marsh and a swamp? A marsh is a wetland on the edge of a lake or stream that is often flooded by water. A swamp is a wetland that has water saturated soil. The marsh is at the edge of the water, where it reaches the ground. The swamp is the next
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Why do crabs walk sideways? They walk sideways so they don’t trip over their legs. However, some crabs do walk forwards. There are many different species of crab and they can live in saltwater and in freshwater. The smallest crab is the pea crab, which is only a few millimeters across and is a parasite
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Why was the Hoover Dam so difficult to build? Because the river was very strong and the dam was so big, the concrete would take 125 years to set. A new source of irrigation and drinking water was needed by the end of the 19th century as more and more people settled the south west
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What was the last Apollo mission? The last Apollo mission was Apollo 17. The Apollo program stretched from 1967 until 1972. There was supposed to be an Apollo 18, 19, and 20 but they were all cancelled. The booster for Apollo 20 was repurposed to launch Skylab, America’s first space station into orbit. The decision
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