I’m starting to see this stuff more places. This one could be fun. This one is easier mathematically than the Penny Pyramid that Dan Meyer describes here. In Dan’s 3 Act Format, here it is.
Act I
Ask the kids what they wonder about. They could go lots of interesting directions with this one.
Act II
This video will give them the information they need, assuming their perplexing questions require them to know how many watermelons are in the pyramid.
Act III
The answer is in the form of a Word document with a photo and some calculations. I’d love a video. If anyone has the budget for 385 watermelons, the patience to stack them, and the video editing skills to insert a counter to the filmed stacking, I’d gladly take it.
Sequels
What is the mass of the pyramid?
What is the cost of the pyramid?
How many watermelons could we stack in this room?
If the truck is 20 m from the pyramid, how long would it take to build?
Any other sequels? If so, throw them into the comments.
Download
This zip file (29.7 MB) contains both videos.

If you stacked every watermelon there, how tall would that be?
John, I loved this Amazing Race episode, as so many groups had issues with the structural integrity of their pyramids. All groups started by making the 10×10 watermelon base, then placing the 9×9 on top. It made me wonder if there is a better “mousetrap”. Is there an optimal strategy for stacking the melons.
Would it make more sense to start with a 2×10 base, then start the next level (a 1×9 row) on top of that. Then do the next row of 10, then the next row of 9 on top of that…in which case you’d be ready for the first row of 8. I thought perhaps this approach would increase even-ness at all levels, rather than having a few good levels, then some which we hope stay intact.
Or maybe I need to get out more….
Great blog. Please visit mine and say hello: mathcoachblog.wordpress.com
Tried this today with low ability Y8 – no watermelons, but built with Maltesers!
How did it go?
I had to Google “Maltesers”. Now I want some!
You’ve never had Maltesers!
It worked really well; they settled really quickly and were hooked by the video, later in the day they were heard telling other students “we did watermelons in maths today” and then explaining what this meant. They came up with varied ways to represent their recording/working out in diagrams and pictures as well as calculations. It is the first idea of this type that have used with a lower group. The maltesers were an afterthought as I remembered I had some for a prize, so after we built pyramids we had to eat them of course!
Thanks for suggesting this.