In the 1440s, Johannes Gutenberg invented the printing press and changed the world. It is not very often where you can say that an invention caused such enormous ripples that without it, we wouldn’t be where we are today. The wheel seems an obvious example. The printing press made the spread of information, knowledge, discoveries, […]
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What will happen to the Voyager spacecraft? Unless they collide with anything, they will probably keep going for several billion years. Voyager 1 is currently 24.3 billion km away from Earth and Voyager 2 is 20.3 billion km away. Despite being called number 2, Voyager 2 was launched in August 1977, a month before Voyager
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Is moss one plant or many plants? A patch of moss is made up of many plants. There are many types. There are approximately 20,000 species of moss plants and some of them are huge. The Dawsonia moss grows up to 50 cm tall. However, most moss plants are much smaller than that. Mosses have
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What is the difference between a slave and a serf? A slave is the property of the person who owns them while a serf is bound to the land they live and work on for generations. Civilizations have taken slaves for as long as one group of people has fought another group of people. It
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Why do we hiccup? Hiccups are caused by muscular twitches in the diaphragm. The diaphragm is the muscle that we use to breathe. It is a dome shaped muscle that is below the lungs. It is connected to the sternum at the front, the bottom of the rib cage and the spine, to make a
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Why does hair turn white? The pigment cells in the hair follicles die. Our hair is colored by melanin that is produced by the pigment cells in each hair follicle. Melanin is what colors our skin as well. Melanin is produced in cells called melanocytes and different quantities or types of melanin can alter the
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Why does the medical symbol have a snake and a staff on it? It is the Rod of Asclepius, an ancient symbol of medicine. If you have the misfortune to require an ambulance in the US, you will notice that it a) costs an awful lot, and b) has a six pointed blue star with
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Alexander Cumming invented the S-bend in 1775. Toilets have existed for thousands of years, but the S-band (now the U-bend) was an invention that helped transition to indoor toilets and helped to improve sanitation levels around the world. Early people used streams running near their settlements for a toilet. That is fine, so long as
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Why are blueberries blue and strawberries red? Because of the animals the plants want to eat their fruit. Flowers and fruit tend to be a certain color because they have either evolved to attract a certain kind of animal or to repel a certain kind of animal. A lot of flowers and animals as well
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What is a crusade? It is a Catholic expedition called forth by the pope for various religious purposes. If it doesn’t have the pope’s blessing, it is not a crusade. The word “crusade” means a military expedition under the banner of the cross. The first crusades were in the 11th century and the word “crusade”
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