I learned this today. Floor indicators were added to elevators in the 1950s in order to distract people while they waited. The actual waiting time wasn’t as bad as the perceived waiting time. This was discovered thanks to queuing theory. Queuing theory was invented by Agner Krarup Erlang in 1909. He was working for the […]
#29 Why will people happily wait in a queue? Read More »
I learned this today. We can’t see colors in the dark because our eyes detect light waves in two different ways. In our eyes, we have rods and cones that are both used to detect light. The cones are sensitive to light wavelengths, and we use them to see color. The rods are sensitive to
#28 Why can’t we see color at night? Read More »
I learned this today. Why would we evolve with a throat and windpipe that are so close together we can choke? In 2019, 5228 people choked to death in the United States. As a cause of death, it was the fourth highest. Chocking happens when an object, typically food, blocks the throat or windpipe cutting
I learned this today. The horse collar changed society in a huge way and many things we take for granted now came about because of the horse collar. There are different opinions, but humans probably started farming about 11,500 years ago. Many animals were domesticated at around this time as well. Fields were dug and
#26 How did the invention of the horse collar change society? Read More »
I learned this today. Why is Wall Street called “Wall Street” and why has it become a financial center? There are two theories as to why Wall Street is called Wall Street. Nobody knows which one is true. The first theory is that it was a street for a people called Walloon. At that time,
#25 Why is Wall Street called Wall Street? Read More »
I learned this today. What causes water mirages and heat hazes? Water mirages and heat hazes are caused because light travels at different speeds through warm air and cold air. Light travels at 299792458 m / s in a vacuum. When the light from the sun hits our atmosphere, the density of the air causes
#24 What causes water mirages and heat hazes? Read More »
I learned this today. An electric eel produces electricity in the same way that a battery does. Electric eels usually grow to be about 2m long and they have three organs that they use to make electricity. These are called the main organ, Hunter’s organ, and Sach’s organ. These three organs take up most of
#23 How do electric eels make electricity Read More »
I learned this today. The piano is only 300 years old and many famous composers that we know composed for the harpsichord, not the piano. The piano was invented by Bartolomeo Cristofori in about 1698. He worked for the house of Medici. He called his invention, “un cimbalo di cipresso di piano e forte,” which
#22 Why was the piano invented? Read More »
I learned this today. Most TV remote controls operate by sending binary signals to the TV using infrared light. The remote controller in your house has an LED fitted to the end of it. This LED emits a wavelength of 940 nm, which is infrared. The human eye can only detect wavelengths between 380 and
#21 How do TV remote controllers work? Read More »
I learned this today. Cats appear never to blink, but they actually blink with a third eyelid, a nictitating membrane, which is difficult for us to see. Most animals that have eyes blink. Insects with compound eyes can’t blink, and fish, snakes, ghekos, slinks, and some lizards don’t need to blink. Apart from these, blinking
#20 Do cats blink? Read More »
