Where do modern military ranks come from? There is not one single point where they started. Many countries have different systems and they have all evolved over time. Most of the ones we use in the West came from Italian and French. You don’t need ranks unless you have an organized army. In the beginning […]
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How is salt mined? In the same way that any other mineral is mined. There are three ways of producing salt. It can be mined out of the ground, it can be mined as a solution, or it can be left after the water is evaporated away. Salt on Earth is usually found underneath the
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How does a missile shield work? Attacking missiles can be brought down in the boost phase, the midcourse phase, and the terminal phase. Each phase of the missile’s path requires a different method to bring it down. A missile defense shield was first thought about in the Second World War. Germany had invented the V-2
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Why does a cracked whip make a sound? One portion of the whip moves faster than the speed of sound, creating a sonic boom. A sonic boom is created by anything that goes faster than the speed of sound, which is 343 m/s in air. Air behaves in the same way as a fluid, so
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Why is there a plastic island in the Pacific Ocean? Because of the amount of plastic waste we throw into the sea and because of the point where ocean currents converge. There are plastic islands in all of the oceans on Earth, not just the Pacific. The Great Pacific Garbage Patch just happens to be
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How many people do you need for a revolution? You need 3.5% of a population to start a revolution. There have been countless revolutions throughout human history. The ones that probably stick in our minds (depending on where we are from) are the French Revolution from 1789, the American Revolution from 1765, the Chinese Revolution
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Do the three laws of robotics need updating? The three laws of robotics were an invention by Isaac Asimov and they were meant for a story, not to be a literal way of controlling the robots and AI in our lives today. We will need some kind of laws that robots have to follow at
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Is “I think therefore I am” true? Probably. “I think therefore I am” is probably the most famous philosophical quotation of all time. It is probably the only one that most people will have heard of. It was coined by René Descartes in 1637. He was born in France in 1596 and he was a
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How can opera singers sing so loud? By training their diaphragm, their lungs, using their mouths to amplify the sound as much as possible, and adjusting the frequency of the sound they are making. Opera singers are louder than the average person, but they also have a way of making their voices easier to hear,
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Why do we say “hack writer” and “quack doctor”? Hack comes from Hackney and quack comes from quacksalver, the Dutch for a seller of medicines. A hack has a negative image, but there is no reason why it should. The word was first used in about 1700 to refer to someone who is hired to
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