We can’t live without water. We need it to stay hydrated and grow food. We use it to generate electricity. Water is in us and all around us. It makes […]
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.