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 »
I learned this today. There are different types of stem cells, but they basically work by developing into different types of cells. There are 200 different types of cells in the body, and they all do different tasks. For example, neurons in the brain, white blood cells that fight infection, muscle cells, and the
#137 What are stem cells and how do they work? Read More »
I learned this today. A letter of marque was a license from a government for a private citizen to attack and capture vessels of an enemy nation in order to gain reprisal for that country’s actions in a war. It was very expensive for a country to have a standing navy and a lot of
#136 What is a letter of marque? Read More »
I learned this today. Bluetooth is a short range, low power technology that can transmit data over radio waves. Bluetooth works on frequencies in the 2.400 to 2.483.5 GHz short-range radio band. Radio frequencies around the world are generally regulated so that different frequencies don’t get mixed up. That is why different radio stations broadcast
#135 How does Bluetooth work? Read More »
I learned this today. Diazepam is a benzodiazepine drug that works by increasing the amount of a chemical called GABA in the brain to inhibit electrical impulses. GABA is Gamma-aminobutyric acid. It is a chemical that your brain produces. It is an amino acid and is an inhibitory neurotransmitter in the brain. It inhibits brain
#134 How does Valium (diazepam) work on the brain? Read More »
I learned this today. Corals are animals because they don’t produce their own food. Corals are sometimes thought to be rocks and sometimes thought to be plants, but they are neither. They are animals. They are thousands of tiny animals collected together. Because of this, they are known as colonial organisms. They belong to the
#133 Is coral a plant or an animal? Read More »
I learned this today. The first account of a crime syndicate that was an American Mafia was published in the New Orleans Times in 1869. It could be argued that the Mafia started in Italy during the end of the 16th and the start of the 17th centuries. Its vertical structure, with a don at
#132 When did the Mafia come to America? Read More »
