I learned this today. The Bronze Age started because people discovered that combining copper and tin made a stronger alloy called bronze. In the three-age system of the world that we use, the Bronze Age technically follows the Stone Age and is in turn followed by the Iron Age. However, it isn’t quite that clear […]
#147 Why did the Bronze Age start? Read More »
I learned this today. Gas masks work by blocking bacteria and viruses, or by absorbing or altering chemicals. Gas masks have to be effective against bacterial, viral, and chemical agents. Bacteria and viruses are technically the easiest because all the gas mask has to do is block them. This is done with a filter. The
#146 How do gas masks work? Read More »
I learned this today. The Portuguese royal court moved to Brazil in 1807 to avoid being deposed by Napoleon. Spain and Portugal both started exploring the Southern Americas from the late 15th century. Portugal claimed the area that is now Brazil for the King of Portugal in 1500. The Portuguese explorer who claimed Brazil for
#145 Why did the Portuguese royal family end up in Brazil? Read More »
I learned this today. There are two ways to work out the age of the universe. The first is to calculate the age of the oldest stars. The second way is to work out how fast the universe is expanding and cooling and extrapolate backwards. The universe is thought to be 17.772 billion years old,
#144 How do people know the age of the universe? Read More »
I learned this today. The first drink put in a can was beer in the 1930s, but it took a while before drink canning could be perfected. The process of canning was invented by Nicolas Appert in France in 1809. He was responding to a challenge by Napoleon Bonaparte for anyone that could come up
#143 When did people start putting drinks in cans? Read More »
I learned this today. Venus and Uranus spin in the opposite directions to the other planets possibly because Venus flipped over and Uranus was hit by another planet. Our sun rotates anticlockwise, and it takes about 27 days to complete one rotation. Because the sun rotates anticlockwise, all of the planets in our solar system
#142 Why do Venus and Uranus spin the wrong way? Read More »
I learned this today. The different rocks of Stonehenge came from three different places. Stonehenge was probably built between 3000 and 2000 BC. Originally, it was constructed with wood. Wooden posts dating from 8000 BC have been found there, suggesting that it has been a place of significance for a long time. The first Stonehenge
#141 Where did the stones of Stonehenge come from? Read More »
I learned this today. Erasers work because of friction. They become sticky when they are hot and hold onto the graphite particles. Before we look at how erasers work, I think we need to look at how pencils are able to write on paper. Pencils are made with graphite. These days the graphite is mixed
#140 How does an eraser work? Read More »
I learned this today. There have been six mass extinctions on Earth that experts know about. The Great Oxidation Event about 2.4 billion years ago. The Ordovician-Silurian Extinction 440 million years ago. The Devonian Extinction 365 million years ago. The Permian-Triassic Extinction 250 million years ago. The Triassic-Jurassic Extinction 210 million years ago. The Cretaceous-Tertiary
#139 What are the six great mass extinction events? Read More »
I learned this today. The Jolly Roger was the flag used by pirates, but nobody really knows why it was called the Jolly Roger and there were many different versions of it. We generally think of pirates as being people like Blackbeard and Captain Kidd and most of these pirates operated in the Caribbean. The
#138 Did pirates really use the Jolly Roger flag? Read More »
