#16 Where do the plus, minus, multiplication, and division symbols come from?
I learned this today. The mathematical symbols + plus, – minus, x multiply, ÷ divide, and = equal are not as old as we think. Mathematics itself goes back a…
I learned this today. The mathematical symbols + plus, – minus, x multiply, ÷ divide, and = equal are not as old as we think. Mathematics itself goes back a…
I learned this today. Canning preserves food by killing all of the bacteria present through heat and then keeping the food in a bacteria-free, airtight can. For food to rot,…
I learned this today. Leather is strong because the collagen fibers in the animal skin are strengthened and bolstered by other chemicals. It can take up to ten weeks to…
I learned this today. A gun silencer works by reducing the speed of the gases that push the bullet out of the barrel, but it cannot silence the sound of…
I learned this today. Alcohol gets people drunk because it is a depressant and slows down the speed at which the brain can send signals. Most alcoholic drinks contain ethanol…
I learned this today. Before the invention of the elevator (lift for my British friends), wealthy people lived on the lower floors of a building because they didn’t want to…
I learned this today. Seasickness is caused because of a discrepancy between the vestibular system and the eyes. Just inside your head, you have your inner ear which is used…
I learned this today. An airbag can inflate so quickly because it contains sodium azide, which produces nitrogen gas when it ignites. When you are in a car crash, a…
I learned this today. Vantablack is the blackest material ever made because it absorbs 99.965% of light. Anything that you have in front of you right now is reflecting light…
I learned this today. Salt preserves food by removing the water and vinegar preserves food by increasing its acidity. The refrigerator was invented in 1834. Before that, people used ice…