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 »
I learned this today. Bats can sleep hanging upside down because they need to use muscles to open their claws but not to keep them closed. The main reason that bats sleep hanging upside down is because they are not very good at taking off from the ground. In order to fly, bats have to
#65 How can bats sleep hanging upside down? Read More »
I learned this today. The difference between AC and DC current is that in DC the charge only flows in one direction but in AC it changes direction periodically. Direct current (DC) was first produced in 1800 by the Italian physicist Alessandro Volta. That is why the volt is named after him. He produced electricity
#64 What is the difference between alternating current (AC) and direct current (DC)? Read More »
I learned this today. We feel pain when we touch something very cold or very hot because of thermoreceptors in our skin that are activated by different proteins. Humans are able to withstand a fairly large range of temperatures, but we have to wear clothes to do this. Ancient humans started wearing clothes about 780,000
#63 Why do we feel pain when we touch cold or hot things? Read More »
