Lesson 2 of 10
Hard or soft?
Show on a big screenPress an eraser and it dents. A small dip forms. Press a steel spoon and it does not. Which one is harder?
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The idea
The steel spoon is harder than the eraser.
A hard material is hard to press in or scratch. A soft material is easy to press in.
Try to scratch one material with another. The material that leaves a mark on the other is harder.
Step 1 of 4
- A steel file and a piece of glass.
- The file scratches the glass.
- The glass leaves no mark on the file.
- The file is harder.
Try the lab to finish this lesson.