Why do we say “born to the purple”? What is Tyrian purple? We say that someone who is born into a royal or powerful family is “born to the purple” because Tyrian purple was an incredibly expensive color that only wealthy and powerful people could afford. The dye for Tyrian purple was made from the […]
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Is an Olympic gold medal really made of gold? The gold medal the winners at the Olympics get is only 7.5% gold. It is 92.5% silver with only a gold-plating of about 6g. With 6g of gold in a medal, the value of the medal would be about $800 if sold for its precious metals.
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Why is oil measured in barrels? Oil is measured in barrels because that was the size of a wine barrel in 1866. Nobody really knows when barrels were invented, but there is a picture of a wooden barrel made to measure wheat on the wall of the tomb of the Egyptian high official, Hesy-Ra, from about
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Why are katana blades curved? They are curved to make them more efficient at cutting. Katana are long, curved swords from Japan. Their name “katana” means one-sided blade. “Kata” means “side” and “na” means blade. Many swords are double-sided because it allows them to be more effective when thrust. They can also be used to
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What makes rain smell? A combination of plant oils, bacterial spores, and ozone. Everything always smells very fresh after a rainfall and there is a word for it. Merriam-Webster defines petrichor as, “a distinctive, earthy, usually pleasant odor that is associated with rainfall especially when following a warm, dry period”. The word was invented by
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How does dry cleaning work? Clothes are soaked in a water-free liquid solvent. Dry cleaning is a way of washing clothes without water. At home, all of us wash our clothes in the washing machine using some kind of detergent and water. Inside the washing machine is something called an agitator. This is a drum
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What is in toothpaste? It usually has fluoride, abrasives, flavors, humectants, and detergents. So, what do all of these things do? Fluoride is a naturally occurring mineral. It can be found in most places on Earth, and it is also present in our bodies. Our bodies use it to strengthen our bones and teeth. Fluoride
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By Pablo Picasso – wordpress, PD-US, https://en.wikipedia.org/w/index.php?curid=38782663 What is cubism? Cubism is an art form where the artist tries to show an object from multiple viewpoints at the same time. Pablo Picasso is credited with inventing cubism in about 1907, but he wasn’t the only artist experimenting with shapes, he was only the most well-known
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How long does a 747’s runway need to be? A Boeing 747 airplane needs a runway that is at least 2,300 m long to land and over 3000 m to take off. However, this is a difficult question because there are many variables that come into play when determining the necessary length of runway for
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Why are there many different types of screw head? The different types of screw head allow for different amounts of torque and for use by different machines. There are over 30 different types of screw head. Prehistoric people generally joined things together using adhesives. The earliest known adhesive was a tar made from heating birch
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