Lesson 6 Rocks and Soils: Attributes Hardness

Hello, young scientists!

Let’s get into our fourth and final attribute of rocks and minerals: hardness.

Hardness is exactly what it sounds like: how hard a rock or mineral is.

Look at the digital poster below to see how hardness is measured using something called the Mohs hardness scale. The column to the far right on this poster shows you the hardness of everyday objects you’re familiar with.

Get your science journal and collected rocks ready for today’s activity. We are going to test the hardness of your rocks!

 

visual Visual

Hardness chart

Hardness alt tag.docx Download Hardness alt tag.docx

 

Assignment

Materials needed:

  • your science journal
  • a pencil
  • colored pencils
  • rocks you collected three days ago
  • a penny

Science Journal Entry:

  1. To test the hardness of a rock, take one of the rocks you collected and scratch it against another rock. Did it leave a streak or line of color? If it did, that means it is harder than the rock it scratched. If the rock you scratched does NOT have a streak on it, that means it is the harder rock. Illustrate what happened between these two rocks in your science journal.
  2. Now rub one of your rocks against the penny (with your parent’s permission, of course!). Did the rock leave a streak or scratch on the penny? What does the result of this scratch test tell you about the hardness of the rock? Illustrate what you saw and record your response.

 

 

 

 

[CC BY 4.0] UNLESS OTHERWISE NOTED | IMAGES: LICENSED AND USED ACCORDING TO TERMS OF SUBSCRIPTION