1. There are different kinds of fossils
Petrified
Molds and casts
Carbon film
Trace
Preserved remains

2. Petrified Fossils
Forms when water that is rich in minerals seeps into spaces in cells and then over time evaporates out.
When the water evaporates it leaves the minerals behind.
The minerals turn harden and turn the organism to stone

4. Molds and casts
A mold is a hollow area in sediment where an organism used to be
A cast is a copy of the shape of the organism
Cast Fossil
Mold fossil

5. Cast
Mold

6. Carbon Film
The organism leaves an extremely thin coating of carbon on a rock
Gases escape from the sediment and leave carbon behind

7. Trace Fossils Provides evidence of animal activity. Example:
Footprint / Caves
Poop

8. Preserved Remains (body fossils)
Some processes preserve the remains of organisms with little or no change
Tar pits
Amber
Freezing