The mohs scale
Did you know there is a way of classifying the hardness of rocks?
Try and find out which rock is the hardest on earth and which one is the softest.
This will give you a bit of background on the Mohs scale.
Make up your own mohs scale of things you can find around your house and rank them from 1-10. (You can just use feel….and they don’t need to be rocks!) For example, lego is very hard when you step on it with bare feet!