Soil is made up of different layers. How far down do you need to dig to find the soil horizon, or the place where bits of leaves and branches become soil?

With this cool floating rocks project, your child will get some hands-on experience with buoyancy and learn why certain rocks like pumice are able to float.

Science fair project which tests various sedimentary, igneous and metamorphic rocks to find out whether one rock family is stronger than the others.

How do organic materials become soil? This science experiment measures what materials biodegrade.

Check out this cool science fair project on identifying rocks and minerals for kids.

Science fair project that compares the ecology of different soil samples by identifying which sample has the most invertebrates living in it.

Test out the pH levels of soil in your backyard versus soil in more wild environments to solve this science case.

Find out whether soil amendments can improve soil conditions and help you grow a bigger beanstalk in this ecology experiment!

This science fair project idea measures and compares effects of chemical weathering, specifically carbonation, on different kinds of rocks.

Learn how different types of soil affect how animal tracks form in this experiment!

Soil and energy don't go together, right? That would be as bizarre as a pairing of peanut butter and marshmallows! Well, actually...

Science fair project that identifies the differences between soils from different environments and attempts to figure out why those differences exist.

The objective of this science fair project is to test the growth rate of a plan in a crystal medium in comparison to traditional soil.

This fun and easy middle school science fair project idea explores the topic of pollution and demonstrates if polluted soil affect the growth of green plants.

Play with balance and simple engineering as you hurry to create a sturdy rock tower.

Check out this cool science project idea to learn about rocks and explore the cycles of formation, breakdown, and reformation of rocks in the Earth's crust.

What is mulch? Kids will provide soil with a wet blanket of mulch and see if that helps keep drought-stricken soil damp.

Do plants get crowded? Have your curious kid investigate how plants respond if they're forced to grow together in a confined space.

Science fair project that examines the behavior of water and gravel in creek beds and the formation of sedimentary rocks.

Kids learn how to prevent erosion by growing grass. They'll test soil with grass against raw soil in this revealing science fair project idea for 4th grade.

This science fair project idea studies which kind of rock (sedimentary, igneous, or metamorphic) is most damaged by frozen water.

Determine which kind of rock (igneous, sedimentary, metamorphic) has the greatest reservoir capacity, which is the ability to hold the most oil and natural gas.

Did you even wonder why some rocks are round and smooth while others are broken up into small pieces?

In this experiment, students will discover how heat and pressure turn clay into slate, phyllite, and finally schist.

Wiggly worms are known for staying buried in the soil, but how does that affect plants? Are earthworms and plant growth related?