Preparing for the challenge! They started practicing with their rubber bands before the actual showdown.
Making connections to the activity. Got them to write down the energy changes taking place in their bodies while shooting rubber bands on the Bull’s eye board. 
Both managed to get the energy conversions written down. I helped to refine some of it. 
2nd activity. Tearing paper! It’s recycled paper, so it’s not that wasteful. I demonstrated how to tear the paper to get the results I wanted 
Their final challenge is to ‘make a mountain out of a molehill’, ie, to stack the bits into as high as they could within 1 minute. Again, I got them to think of the energy changes taking place in them as they were carrying out the activity. Meaningful interaction and engagement. The last part of the lesson was to complete some seat work as part of practice.