1. Earth was different millions of years ago. Plants and animals were different too. But how do we know that? Some plants and animals became fossils. Scientists study collections of fossils to learn about the past.
2. Different plants and animals lived on the earth long ago. Some them became fossils after they died. The fossils formed from their remains. Remains are the parts left behind after a plant or animal dies. Bones are a type of remains. Sometimes they become fossils.
3. Making fossils takes a long time. When animals die, their bodies decay. Decay means to rot and go away. The soft parts like skin decay first. This takes months. Then hard parts like bones decay. This takes a few years. But sometimes the bones become fossils. This takes many, many years. Wind and water cover the bones with sand and mud. The sand and mud make layers on top of the bones. The layers slowly become rock. The bones can become fossils.
4. Finding fossils is hard. They are covered by layers of sand and rock. Fossils can be uncovered a few different ways. Erosion helps us find fossils. Erosion is when wind and water push away layers of sand and rock. The fossil gets uncovered. Another way is when water dries up. You can find fossils that used to be at the bottom of a river. In other places, rocks may crumble and crack. This can uncover a fossil too. Maybe one day you will find a fossil!
Written by EL Education for instructional purposes.