How and Why03755_000_009
1. How does grass grow through hard ground? Each blade has a fine, hard point that forces its way between particles of soil, making a path for the blade to follow.
2. How far can a person see? Most people can see to any distance from which light can reach their eyes. The distance to the farthest visible star is hundreds of millions of kilometers.
3. How much salt is there in the sea? One estimate is that there is enough salt in the oceans of the world to cover all of South America to a depth of 1.12 kilometers weighing several trillion tons.
4. How high do waves rise? Off the Cape of Good Hope near the southern tip of Africa, waves sometimes exceed 40 feet or 12 meters in height. Researchers calculate that during freak storms in the North Sea waves could approach 60 meters in height.
5. Why does electricity give people a shock? It suddenly and violently causes their muscles to involuntarily contract.
6. Why does a stream run faster in the middle? Friction against stones and earth at the sides slows the water. For the same reason, water runs faster at the surface than near the streambed.
7. How can ostriches digest nails? They can’t, though sometimes they swallow them. Having no teeth for chewing, they need hard objects to aid their digestion. Most birds eat sand and gravel for that purpose.
8. Was Cinderella’s slipper really made of glass? Her slipper was not glass; it was fur. An old French word for fur is vair. In the translation of the original French story into English, vair was mistaken for verre, the word for glass. Fur was a symbol of high rank in those days. Naturally, Cinderella would wear a fur slipper befitting royalty.
9. How many ancestors do I have? The number of direct (parent to child) ancestors doubles every generation for about a dozen generations. Allowing thirty years for each generation, you have had more than 8,000 ancestors since 1620.
10. Why were canaries once taken down into mines? Since a canary’s blood circulates faster than a man’s, a canary would die before a man if odorless poison gases were present. Miners could then retreat to the fresh air before it was too late.