What causes pins and needles? Pins and needles are caused because the flow of blood to your nerves is restored. Pins and needles are really called paresthesia. The word comes from the Greek para, which means “abnormal” and aesthesia, which means “sensation”. They come after one of your limbs has fallen asleep, which is actually […]
#458 What causes pins and needles? Read More »
Is an Olympic gold medal really made of gold? The gold medal the winners at the Olympics get is only 7.5% gold. It is 92.5% silver with only a gold-plating of about 6g. With 6g of gold in a medal, the value of the medal would be about $800 if sold for its precious metals.
#457 Is an Olympic gold medal really made of gold? Read More »
When did people start using glass for windows? The Romans were the first people to have glass in their windows, but it wasn’t a common practice to have glass windows until the 17th century. There have been window holes since there have been houses because it is necessary to let the light in during the day.
#456 When did people start using glass for windows? Read More »
Why do we get goosebumps? Goosebumps are a reaction left over from when humans used to have a thick coat of fur. I’m sure you have all experienced goosebumps at some time in your life. It is when bumps appear on your arm that resemble plucked goose skin. In fact, the medical term is cutis
#455 Why do we have goosebumps? Read More »
Why do we still have wisdom teeth if we don’t need them? Because they appear after birth, which means it is very difficult for evolution to select against them. Wisdom teeth are a third set of molars that appear at the very back of the jaw. Molars are the large flat teeth that are used
#454 Why do we still have wisdom teeth if we don’t need them? Read More »
When were sunglasses invented? The first sunglasses were used by the Inuit people tens of thousands of years ago. The Inuit people lived, and still live, on the Arctic regions of Greenland, Canada, and Alaska. Snow blindness is a problem that they have always had to deal with. Snow blindness is not caused by the
#453 When were sunglasses invented? Read More »
What is the densest material in the universe? Osmium is the densest material on Earth, but the densest material in the universe (that we know of) is that of a neutron star. What is density? Density is the amount of mass that something has in relation to the space that it occupies. For example, a
#452 What is the densest material in the universe? Read More »
What were the moa and what happened to them? The South Island Giant Moa was a 3.6 m tall bird that were hunted to extinction by 1445. The Moa were flightless birds that lived in New Zealand. They were very similar to ostriches, but about a meter taller. When they stretched their necks up, the
#451 What were the moa and what happened to them? Read More »
Why is oil measured in barrels? Oil is measured in barrels because that was the size of a wine barrel in 1866. Nobody really knows when barrels were invented, but there is a picture of a wooden barrel made to measure wheat on the wall of the tomb of the Egyptian high official, Hesy-Ra, from about
#450 Why is oil measured in barrels? Read More »
What are contact lenses made of? Soft contact lenses are made of an oxygen permeable soft plastic. Hard lenses are made of a plastic like Perspex. There are generally two types of contact lenses: soft and hard. Soft lenses are made of a soft plastic. These days, the plastic used is silicone hydrogel. Silicone hydrogel
#449 What are contact lenses made of? Read More »
