Cast Fossils: Fossils In Your Very Own Hands!

Lesson Plan - Get It!

Audio:

• Have you ever heard of a fossil before?

• Do you know what a fossil is?

A fossil is a piece (what is left over) or trace (like a footprint) of an animal, plant, or object that has been preserved over time.

As you can see from the images below, a process known as fossilization must take place to create a fossil. Check it out!

When the fish perishes, its body sinks to the river bed. Over time, the body of the fish decays and is eaten by bacteria. However, the bones are left!

Eventually, those bones get covered with layers of soil, rock, and minerals. Those minerals then replace the bones. One day, the earth will move, and the fossil will be closer to the surface, where someone can find it!

It may be hard to know what things looked like thousands of years ago. Looking at fossils provides a way to look into the past!

Mold fossils can show you the footprints of animals, people, and even the impressions of leaves! Over time, they have been preserved for us to see!

• What if you were to make a cast fossil out of a mold?
• Do you know what a cast fossil is?
• Why don't you join Flo to learn more?

• Did you see how the cast fossil formed?

When the plastic animal was used to form an outline in the sand, a mold fossil was formed! However, sand is a very loose material that will never harden well, so it is not a material that is used to form mold fossils in nature.

When you place the plaster slip mixture inside the temporary mold and let it dry, you can make a cast fossil of your plastic animal!

• Can you think of some items that make up most of the mold and cast fossils you find today?

Head to the Got It? section to find out!