Show children the pictures of the different rocks on the slides. How could you organise these rocks into groups? Children to talk through their ideas.
Show children how the rocks have been grouped. What criterion has been used to group these rocks? Children to offer ideas then go through the answer on the slides. Repeat with the second criterion.
Show children how different diagrams and charts can be used to organise rocks into categories. Show children the Venn diagram on the slides. Can you think of a rock that would go in the middle of the two circles? On the next slide, ask children to see if they think the rocks have been sorted correctly on the Venn diagram, giving reasons for their answers.
Why do you think it is important to be able to group rocks according to their characteristics? Invite children to share their ideas.