Science Common Sense

37 - What are fossils and how are they formed?

Fossils are remains or imprints of plants and animals from a long, long time ago. They can be formed in several ways:

1. Buried alive: When an animal dies and is quickly buried under mud, sand, or ash, the body starts to decompose. But if it's buried quickly enough, some of its parts like bones or leaves can be preserved.
2. Mold and cast: If the mud around the buried body hardens, it creates a mold of the shape. Over time, water can seep in and fill the mold with minerals, creating a fossilized cast of the original shape.
3. Compression: If a leaf or a small animal is pressed between layers of mud or rock, it can be flattened and preserved.
4. Impressions: If a dinosaur or animal walks on soft mud, it leaves an impression of its foot or body. Over time, the mud hardens and preserves the impression.

Fossils help us learn about the past, including what plants and animals lived on Earth a long time ago and what the environment was like back then.