Book 30, Question 17 · Video
Why are lakes on the Canadian Shield so rocky and clear?
The Canadian Shield is a huge area of very old, hard rock. The rock is mostly granite and similar kinds, which dissolve very slowly, so the lake water carries few dissolved minerals. With so few nutrients to feed algae, the water stays clear. Because there is little limestone to balance acid, many Shield lakes are slightly acidic and can be sensitive to acid rain. These lakes are famous for cottages, canoes, and loons.
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What Crafty Clover says in this video
Intro
Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why are lakes on the Canadian Shield so rocky and clear?
The Big Idea
Canadian Shield lakes are famous for clear water! And lots of rocks. Why?
Ancient Rock
Step one: Ancient Rock. The Canadian Shield is a huge area of very old, hard rock. Some of these rocks are over three billion years old.
Few Minerals
Step two: Few Minerals. The rock is mostly granite and similar kinds, which dissolve very slowly. So the water carries few dissolved minerals, and with so few nutrients for algae, it stays clear.
Sensitive Lakes
Step three: Sensitive Lakes. With little limestone to balance acid, many Shield lakes are slightly acidic and can be sensitive to acid rain. These lakes are famous for cottages, canoes, and loons.
A Closer Look
Let's take a closer look! Hard and old. Few nutrients. Sensitive. Famous calls.
Quick Facts
Quick facts! Some Canadian Shield rocks are over three billion years old. Granite dissolves slowly. Sensitive to acid rain. Great for canoes.
Think Like a Scientist
Now, think like a scientist! Find a smooth, hard rock. Find a crumbly rock. Rub each one with your fingers. Which one loses bits more easily? Which would give more minerals to water?
Outro
The Canadian Shield is made of very old, hard rock like granite that dissolves slowly, so lake water carries few minerals and nutrients and stays clear. With little limestone, many Shield lakes are slightly acidic and sensitive to acid rain. Science is amazing! Keep wondering and keep exploring! Share what you learned with someone at home, and see what they think! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!