Why Does Cooling Lava Crack?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why does cooling lava crack?

The Big Idea

As lava cools, it shrinks. When rock shrinks, it pulls apart and cracks, a bit like mud drying in the Sun. In thick flows, those cracks can make six-sided columns!

Cooling Shrinks

Step one: cooling shrinks. Most materials get a little smaller as they cool, and lava is no different. The rock tries to shrink, but it is stuck to the rest of the flow.

Cracks Start

Step two: cracks start. The shrinking rock pulls apart and forms cracks, a bit like mud drying in the Sun. The cracks tend to meet each other at angles, like the lines on a honeycomb.

Columns Form

Step three: columns form. In thick basalt flows, the cracks often make six-sided columns that look like giant pencils. The cracks run down as the flow cools from the outside in.

A Closer Look

Let's take a closer look! It starts as thick, hot lava. As it cools, it shrinks. The shrinking makes cracks. And the cracks carve the rock into columns.

Quick Facts

Quick facts! The Giant's Causeway in Northern Ireland has thousands of columns. Devils Postpile in California is another famous place. The columns are often six-sided, but can have four to eight sides. Stay on the paths when you visit, because the rock can be slippery.

Think Like a Scientist

Now, think like a scientist! Mix cornstarch with a little water into a thick paste. Spread it in a dish and let it dry for a day. Look for cracks. What shapes do they make?

Outro

Cooling lava shrinks and cracks, and sometimes makes giant columns. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!