Lasers
Laser lights are used in CD and DVD players. They are used in grocery stores to scan bar c...
Humans have tried for centuries to find a successful repellant to use against mosquitoes. Native Americans used to cover their bodies with goldenseal root to protect themselves from mosquito bites. Today, in back yards across America, candles made from citronella oil are brought out by the dozens to ward off the pesky mosquito. Now researchers have identified a natural remedy that comes from chemicals secreted by frogs. Frog skins are thin, delicate membranes that are especially adapted for the absorption of water from the environment. This fragility makes them vulnerable to predators and parasites. In response frogs have developed the ability to produce chemicals that act as natural repellants. Recent studies have shown that these repellants are effective against mosquitoes. The only known downside of the frog skin repellant is the smell; some of the frogs' secretions stink of rotting meat, which researchers say helps keep biting insects at bay.
Laser lights are used in CD and DVD players. They are used in grocery stores to scan bar c...
A shooting star, that bright flash of falling light in a dark sky, is also called a meteor...
During World War II, the United States needed to transport soldiers, tanks, and other supp...