How Fossils Form Part 1

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SWBAT compare and identify fossils and explain how fossils are formed.

Big Idea

In this lesson, students model the process of fossilization by making fossils using small toy figures and melted chocolate.


8 minutes

I begin this lesson by asking students how we know about plants and animals that lived on Earth thousands of years ago?  (Many students respond with fossils)   Next I ask students to define what a fossil is?  I tell students that a fossil is a remainder of something that lived a long time ago. Many times, fossils can be imprints of footprints or bones. To make a fossil, a footprint or a dead animal or plant first gets covered with soil, mud or silt. Eventually, the organism decomposes and the hard parts (such as the bones) are left to make an imprint in the soil.

Next, I play the first part of this video. I stop it at 2:44.  Engaging students in science with short video clips is a common practice I use.  Videos are a great way to show students something new or exciting and instantly hook them in a lesson.  Video clips are also a great way for students to see something and then begin to ask questions and wonder about what they saw. 


 In this video you can hear a student defining what a fossil is. fossil definition


30 minutes

Next I tell students that today, they will make their own fossils.  I show a small toy imprint and ask students to think about how it is different from a real fossil?  I tell students that in the natural world, all parts of the dead organism would decompose so fast that a fossil would not be formed looking like a whole animal. Bones take much longer to decompose, and so fossil imprints are often found of just the bones of an organism or the structure of a plant.

Fossils can give clues to how a region's environment changed over time, and engineers can use this information to create models of global climate change over the life of the Earth. Engineers can even use the knowledge from fossils to develop processes to address global warming and species extinction. Also, engineers are deeply involved in the development of technologies that use fossils (and fossil fuels) for materials and energy production.

I tell students that today, we will focus on the process of how fossils are made, and we'll ignore the fact that most of the organism would be decomposed. Next I direct students to imagine the toy is a dying organism, and it falls to the muddy ground. Eventually, this organism (toy) gets covered by more mud. Over time, the mud hardens so we can break open the mud and observe the fossil (ignoring the now decomposed organism).

Then I tell students we’re going to model this with chocolate instead! Directions for Chocolate Fossils)



Part 1 Wrap Up

10 minutes

To wrap up Part 1 of this lesson, I instruct students to write about the day in their science notebooks by answering the following writing prompt:

Why do engineers care about fossils?  How are fossils made? 

You can see some students responses here. 


Later, when I look at students responses, I will look to see if students answer that engineers learn from fossils. Engineers design technologies to help locate and create three-dimensional imaging of fossils. Fossils can give engineers clues to how things used to work, and engineers can use the knowledge from fossils to develop processes that could help people and the environment today.)