Monthly Archives: October, 2012
How does a camera take pictures?
Camera film is coated with special chemical sensitive to light. A camera is basically a box which light cannot enter, except through a small hole located at one end of the camera. This opening is covered with a glass lens. A shutter opens and closes the hole behind the lens. When we open and close …
How did bands originate?
There were bands as far back as early Egyptian times, when groups of musicians banded together to play harps, drums, and other musical instruments. Everyone likes to hear a band! People march to the music of marching n\bands in parades. And almost every high school and college has one. The first bands were nothing like …
Where does dust come from?
Housekeepers spend a good deal of time dusting. If you have ever helped clean, or dust, furniture, you may have wondered where all the dust comes from. It seems to be a daily chore, because dust is always with us. Dust settles from the air and makes a gray coating over everything around us. Dust …
Who invented San Francisco’s cable cars?
Andrew S. Hallidie invented the cable car in 1873. They run on rails and are pulled by an endless steel cable. Cable cars are a popular way of traveling up and down the hilly streets of San Francisco, California. Cable cars were invented in 1873 by Andrew S. Hallidie, an American manufacturer of wire cables. …
What is St. Elmo’s Fire?
St. Elmo’s Fire is the flash of light that is seen around ships in a thunder storm. It is an electrical discharge caused by the storm. St. Elmo’s Fire is the name sailors have given to the sudden glow of ghostly flames that can sometimes be men flickering around ships in stormy weather. The “fire” …
Why are marines called leathernecks?
United States marines got their nickname “leathernecks.” They got this nickname because, in the early days, they wore black leather neckbands on their uniforms, presumably to protect their necks against enemy sabers and cutlasses. The Marine Corps is the branch of the armed forces specially trained for duty aboard warships as well as on land. …
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