Why Does the Seafloor Get Recycled But the Continents Don’t?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why does the seafloor get recycled but the continents don’t?

The Big Idea

The seafloor gets recycled, but the continents mostly stay! Heavy seafloor sinks back into the mantle. Lighter continents float too high to sink, like a cork in a bowl of water.

Dense Seafloor

Step one: dense seafloor. The seafloor is made of dense, heavy rock. When it gets old and cold, it becomes even heavier, so it is ready to sink.

Subduction

Step two: subduction. At subduction zones, the seafloor sinks back into the mantle. There it slowly melts and mixes with the mantle, ready to be used again.

Light Continents

Step three: light continents. Continental crust is lighter and thicker, so it floats too high to sink. Old continents even get new bits added over time, like volcanoes and mountains.

A Closer Look

Let's take a closer look! Seafloor is made of heavy, dense rock. At a trench, it sinks into the mantle. There it melts, and the rock is recycled. Continents are too light to sink, so old rocks survive on top.

Quick Facts

Quick facts! Heavy sinks and light floats, even for rock. So the seafloor is never older than about 180 million years. Continents hold rocks billions of years old. Earth is like a giant recycling machine that never stops.

Think Like a Scientist

Now, think like a scientist! Fill a bowl with water, and drop in a cork and a small stone, one at a time. Which one floats, and which one sinks? Which one is like a continent? And which one is like the seafloor? Heavy sinks and light floats!

Outro

The seafloor is recycled, and continents stay on top. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!