Who invented the cat door?

Who invented the cat door?

In an apparent early modern example of urban legend, the invention of the pet door was attributed to Isaac Newton (1642–1727) in a story (authored anonymously and published in a column of anecdotes in 1893) to the effect that Newton foolishly made a large hole for his adult cat and a small one for her kittens, not realizing the kittens would follow the mother through the large one.

How long does it take for your eyes to adjust to the darkness?

On an average it takes 30 to 45 minutes for your rods to be fully dark adapted to night vision. It also covers things such as Mesopic vision and Scotopic vision, eye health, and how to actually dark adapt. I suggest it as a good read.

What did Charles Lindbergh do to become famous?

Charles Lindbergh (1902 – 1974) Introduction. Charles Lindbergh was a famous aviator. In 1927 he became the first man to successfully fly an airplane across the Atlantic Ocean.

Who invented the first vending machine?

The first modern coin-operated vending machines were introduced in London in the United Kingdom in the early 1880s, dispensing post cards. The machine was invented by Percival Everitt in 1883 and soon became a widespread feature at railway stations and post offices, dispensing envelopes, postcards and notepaper.

How many electoral votes must a candidate win in order to win the presidency?

In order to become president, a candidate must win more than half of the votes in the Electoral College (currently that would be 270 of the 538 total electors).

Which is the hardest bone in the human body?

The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with the tibia and patella forming the knee joint. By most measures the femur is the strongest bone in the body. The femur is also the longest bone in the body.

What is the percentage of salt in ocean water?

The concentration of salt in seawater (salinity) is about 35 parts per thousand. Stated in another way, about 3.5 percent of the weight of seawater comes from the dissolved salts; in a cubic mile of seawater, the weight of the salt (in the form of sodium chloride) would be about 120 million tons.

What was the first metal used by man?

Over 4,000 years ago, when it was discovered that minerals could be melted, curiosity led man to combine melted metals (alloys). By accident they made bronze by adding tin to copper (the Bronze Age). Another combination of zinc and copper made brass.