Activate your prior knowledge...
I wonder, how old are some of the trees in our school grounds?
I wonder, how do we calculate this?
Talk to your partner, what were the steps to do this?
I wonder, how can you work out the height of a tree?
What do you think?
What strategies can you use with the resources that we have?
Strategies you can use:
I wonder, what strategy could you use?
What way do you think will be the most accurate?
What resources will you need to be successful?