Halley's Comet
Every seventy-five years, a bright jet of light races across the Earth's atmosphere. T...
About 5,000 years ago, the Egyptians began making paper from a plant called papyrus. Until then, people wrote on heavy clay tablets that were easy to break. The Egyptians cut stalks of papyrus, which grew wild all over the place. They soaked the stalks in water until they became soft. They piled up the stalks and mashed them all together, then let them dry. Then they glued lots of small sheets together into big pieces and sold them to other countries. The Greeks and Romans bought a lot of papyrus, which was very expensive. They couldn't make their own because the papyrus plant grew in Egypt. After a couple of thousand years, the Chinese method of making paper from rags was discovered. This method was much less expensive. Eventually everyone, including the Egyptians, stopped making papyrus. A few rolls of papyrus have been discovered in Egyptian tombs.
Every seventy-five years, a bright jet of light races across the Earth's atmosphere. T...
The South American Galapagos archipelago inspired Charles Darwin's theory of evolution...
Did you know that your skin is an organ? In fact, it is the largest organ in your body. It...