I learned this today. The International Prototype of the Kilogram, kept in Paris, is not accurate enough to be the standard for all kilograms around the world. Different measures for different things have been used around the world since people began measuring things. These measurements were usually related to the human body or common things […]
#108 Why is the official kilogram in France no longer used? Read More »
I learned this today. Adolf Hitler had three brothers, two sisters, one half-brother, and one half-sister. Because of the things he did, it is difficult to see Hitler as a real person, but of course he was, and he has a family. Adolf Hitler was born on April 20, 1889, to Alois Hitler and Klara
#107 Did Adolf Hitler have any brothers or sisters? Read More »
I learned this today. The Milky Way Galaxy orbits the barycenter of the Local Group. The barycenter is the center of mass of two bodies that orbit each other. It is the point that they orbit around. The word comes from Ancient Greek and means “heavy center”. When two objects orbit each other, there is
#106 What does the Milky Way Galaxy orbit? Read More »
I learned this today. Vikings is the name given to the seafaring people from Scandinavia who raided through Europe from the late 8th century to the late 11th century. The Vikings didn’t call themselves “Vikings” and the word wasn’t used to refer to all of the people and the time period until the early 18th
#105 Why do we use the word Vikings? Read More »
I learned this today. Cats don’t so much retract their claws as lift them off the ground using tendons. Their claws are then hidden by their fur. Cats have five claws on their front paws and four claws on their back paws. The front claws are usually sharper than the back ones. Cats’ claws continue
#104 How do cats retract their claws and why can’t other animals? Read More »
I learned this today. Shoe sizes in America and the UK are measured in barleycorns. Nobody knows when people first started wearing shoes, but experts think it might have been about 40,000 years ago. The little toe bones of skeletons found after 40,000 years ago are thinner than the bones found before. They deduce that
#103 Why do we use those measurements for shoe sizes? Read More »
I learned this today. The mile we use today originated with the Roman mile which was one thousand paces. The word “mile” comes from “mille passus”, which means 1,000 paces. Ancient measuring systems all began by using body parts to measure things. The oldest unit of length is the Egyptian cubit, although they didn’t call
#102 Why do we use miles as a unit of measurement Read More »
I learned this today. Light can’t escape from a black hole because of the curvature of space caused by gravity. In physics, gravity is the weakest of the four fundamental forces. The forces are gravity, the electromagnetic force, and the strong and weak forces that exist in atoms. Isaac Newton described gravity as a force
#101 Why can’t light escape from a black hole? Read More »
I learned this today. Flight or fight, the stress response, was first described by Walter Bradford Cannon in 1915. In 1915, Cannon published Bodily changes in pain, hunger, fear and rage. He noticed that when cats were threatened, their bodies released the hormone adrenaline / epinephrine, which lead to a series of other bodily changes.
#100 Who came up with the phrase “flight or fight”? Read More »
I learned this today. A Lagrange point is a point of equilibrium where the gravitational forces of two large objects balance out the centripetal force. A third object can remain motionless in a Lagrange point without having to use any power. Centripetal force is the force that acts on an object in a circular motion,
#99 What is a Lagrange point? Read More »
