**Activity: Modeling the Formation of Fossils**

**Estimated Time to Complete:**
- Total time: 3 weeks
- Active time: 2 to 3 hours

**Materials Needed:**
- A plastic container (about the size and shape of a shoebox)
- Plastic wrap
- Water
- A ruler
- About 3 cups of sand
- Plastic gloves (kitchen gloves or cleaning gloves)
- 10 to 12 leaves (any kind)
- 10 to 12 twigs and sticks

### Hypothesis and Data Collection

The fossils that scientists find and study today formed thousands to millions of years ago. You can simulate the process of fossilization by following these steps:

1. Line the inside of the plastic container with plastic wrap.
2. Let the ends of the plastic wrap hang out of the container. The overhanging ends will allow you to lift out your formation when it’s complete.
3. Pour four inches of water into the container. Use a ruler to measure the correct depth.
4. Add two inches of sand after adding the water.
5. Spread the twigs and leaves in a thin layer on top of the sand.
6. **Stay safe!** Use gloves when handling the leaves and when checking the inside of your model during the weeks to come. Wash your hands and gloves when you are done.

### Part A
After assembling the materials, record your observations. Describe what the setup looks like and the color of the leaves and twigs. Predict what changes will take place over the next few weeks.

### Part B
Put the container in a well-ventilated area or a protected area outside (such as in a garage or a shed). Ensure that the temperature in the area you choose is above freezing (0°C or 32°F). Check the container at the end of one week, and record any changes in the water level and the appearance of the leaves and twigs. Add another two-inch layer of wet sand on top of the leaves and twigs, and let it sit to dry for two weeks.

### Part C
At the end of three weeks, gently lift the formation out of the plastic container and gently break apart the layers. Examine the changes in the bottom and top layers of sand and in the leaves and twigs. Write down your observations.

### Analyze and Extend

#### Part A
Did your predictions match your observations?

#### Part B
Describe the effect of the leaves and twigs on the bottom sand layer. How does this change relate to the process of fossilization?

#### Part C
What was the purpose of conducting this experiment over a three-week period? Would it have the same results over a shorter period?

#### Part D
Based on the experiment, do you think a fossil can form anywhere on Earth, or does fossil formation require certain conditions? Explain your answer.

#### Part E
Scientists found a layer of rock with several different fossils in it, as shown in the image. Based on your experiment, which of these fossils are the oldest and which are the newest? Explain your answer.

Fossil fuels, such as coal and oil, get their names because they form from fossilized organisms trapped under extreme pressure and heat from the center of the Earth. Explain how your model shows the requirements for fossil fuel formation.