You have been dreading and mulling over it all week: the bad letter grade that’s been slapped on your last test. It might have blind-sided you after you walked away […]
The helicopter was invented by the Chinese in the 4th century, more than a 1,000 years before Leonardo da Vinci. It was called the Bamboo Dragonfly and could fly 25 feet (7.6 m) up and down. The first modern helicopter was invented by the French.