Triassic is a time a long time ago when dinosaurs were alive. Imagine going back in time and seeing big creatures with long necks and tails walking around. The Triassic happened after the Permian time and before the Jurassic time. It's like a middle part of a story. There were also other kinds of animals and plants that lived during this time. It was very HOT and DRY in some places, like a desert. In other places, there were lakes and rivers where plants and animals could live. It's just like how some places today are hot and dry, while others have lots of water. Scientists study the rocks and fossils from the Triassic to learn more about how the Earth has changed over time.