When did people start using nails? Bronze nails were used in Ancient Egypt in about 3,400 BC. Before people had nails, there were different ways of joining wood together. Some of these techniques are still used today. The most basic way of joining wood to wood was with wood glue. Animal glues have been used […]
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How can giraffes have such long necks? Giraffes have jointed vertebrae in their neck, a large amount of ligament, and an enormous heart to get the blood to their head. Interestingly, giraffes used to be called camelopards, because they were kind of shaped like a camel and spotted like a leopard. That word came from
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What is the Great Attractor? It is the theorized gravitational center of our Milky Way Galaxy and 100,000 other galaxies. The universe is expanding at a rate of 2.2 million km per hour. All galaxies should therefore be moving at that speed, but it turns out we are not. Our Milky Way Galaxy is moving
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What causes Parkinson’s disease? It is caused by a loss of nerve cells in the basal ganglia part of the brain. Parkinson’s disease is a disease that gets progressively worse with time. It is more common in men than women and it generally starts when people are over 60, although 10% of cases start when
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How do cactuses survive in the desert? They have adaptations in their roots, leaves, and stems that help them retain water and survive in desert conditions. There are about 2,000 different types of cactus. All types of cactus are native to the Americas, except for the mistletoe cactus, which is found across Africa. The main
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What are bruises? They are where blood vessels near the skin’s surface are broken after an impact. There are three layers in the skin: the epidermis, dermis, and hypodermis. The outer layer of our skin, the epidermis, doesn’t have any blood vessels. All of the blood vessels are in the dermis. New skin cells grow
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What is the difference between DVD and Blu-Ray? Their age, size, quality, audio, and the disc reading technology. DVD is an older technology than Blu-Ray. The technology used to read DVDs was invented in 1958 by David Paul Gregg, an American engineer, and James Russell, an American inventor. Gregg invented a way to record video
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How long do black holes last? Black holes will slowly dissolve, but it will take far longer than the length of our universe, so it has never been observed. There are two ways that black holes form. The first way is when a star collapses. As stars die, they burn up all of their hydrogen,
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Why do Greenland sharks live so long? Partly because of their very slow metabolism. Greenland sharks are large sharks that live in the northern parts of the Atlantic Ocean and in the Arctic Ocean. They live near Greenland, hence the name. They can grow up to 7 meters in lengths and they can weigh up
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Why don’t shipping containers fall off ships? Well, they do sometimes, but generally they are fastened down with lashing rods. There are almost 5,500 container ships in the world and they ship over 11 billion tons of cargo around the world every year. The size of the ships has also increased year by year. The
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