I learned this today. All of the black squares in a QR code represent certain pieces of information. QR stands for Quick Response. They were invented in 1994 by Masahiro Hara. He was working for the Japanese company Denso Wave and he got the idea by looking at the black and white pieces on a […]
#75 How does a QR code work? Read More »
I learned this today. Tectonic plates move because the weight of their cold dense side pulls them into the mantle of the Earth. This is called slab pull. Hot things rise and cold things sink. This occurs because hot things have more energy than cold things, so the atoms move more and spread out. This
#74 Why do tectonic plates move? Read More »
I learned this today. There are two ways of making electricity from solar panels. Directly, by using sunlight to make electricity, or indirectly, by using the sunlight to make heat. The sun releases energy in the form of photons. Photons are massless so they travel at the speed of light, 299,792,458 m/s. They travel from
#73 How do solar panels generate electricity? Read More »
I learned this today. Whales can hold their breath for so long because they can store oxygen in their blood and muscles. On average, whales can hold their breath for about 60 minutes. The sperm whale can hold its breath for about 90 minutes and the Cuvier’s Beaked Whale can hold its breath for 138
#72 How can whales hold their breath for so long? Read More »
I learned this today. Jellyfish don’t have a brain. They also don’t have a stomach, lungs, or a heart. They just have two separate nervous systems. Jellyfish are not fish. They are the medusa-phase of certain gelatinous members of the subphylum Medusozoa. They are in the group of sea creatures called cnidaria. This also contains
#71 How do jellyfish survive without a brain? Read More »
I learned this today. There are different ways that animals can change their colors. Some of the ways take days and some of them take seconds. Let’s look at the slow way first. Some animals change their color very slowly. Some do it by completely shedding their fur. These are mostly mammals or birds that
#70 How do animals change color? Read More »
I learned this today. Gyroscopes work because of the conservation of angular momentum. A gyroscope is useful to us when it is set in a gimbal because the axis of rotation on the gimble is free to assume any orientation, which means that the gyroscope at the center will move independently of the thing the
#69 How does a gyroscope work? Read More »
I learned this today. The Drake equation is a way of trying to guess how many intelligent, communicating extraterrestrial civilizations there might be in the Milky Way Galaxy. Frank Drake is an astronomer who helped found SETI, the Search for Extraterrestrial Intelligence. He co-designed the Pioneer plaque with Carl Sagan in 1972. The Pioneer plaques
#68 What is the Drake equation? Read More »
I learned this today. The QWERTY keyboard was invented because it made it faster for Morse code typists to type. A common story is that the QWERTY keyboard was invented to stop typists from typing quickly. The story goes that when typists typed quickly, the bars that held the letters could jam if they pressed
#67 Why do we use a QWERTY keyboard? Read More »
I learned this today. The Panama Canal has reduced the journey from the Atlantic Ocean to the Pacific Ocean by 8,000 nautical miles (14,818 km), about 22 days. Before the Panama Canal was built in 1914, boats would have to either sail around the southernmost point of South America or up through the Bering Strait.
#66 How much time does the Panama Canal save a ship? Read More »
