Why does frozen ground push rocks up to the surface?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why does frozen ground push rocks up to the surface?

The Big Idea

Every spring, farmers in cold places find new stones in their fields. Where do they come from? Frozen ground pushes them up!

Freezing Water

Step one: Freezing Water. When water in soil freezes, it expands and pushes the soil upward. This is called frost heave.

Thawing Out

Step two: Thawing Out. When the ground thaws, the soil settles. But stones that were lifted do not drop back down exactly, because loose soil slips in beneath them.

Many Winters

Step three: Many Winters. Over many winters, rocks slowly work their way to the surface. That is why farmers in cold places find a fresh crop of stones in their fields each spring.

A Closer Look

Let's take a closer look! Water fills the soil. It freezes into ice. The ice lifts the soil and stones. Stones end up a little higher each year.

Quick Facts

Quick facts! Frost heave can crack roads and make bumps. It can also lift sidewalks. Some farmers built stone walls from the rocks they cleared from their fields. Ice takes up about one tenth more room than liquid water.

Think Like a Scientist

Now, think like a scientist! Fill a small plastic cup with water. Mark the water level with a marker. Ask a grown-up to put it in the freezer. The next day, check the ice. How much did the ice rise above your mark?

Outro

Frozen ground pushes rocks up through frost heave. Freezing water lifts the soil and stones, and when it thaws, the stones do not drop all the way back, so they rise a little each winter. Science is amazing! Remember, every big discovery starts with a small question. Keep looking, keep learning, and keep asking why! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!