If my class takes a trip to the pumpkin farm, we will do pumpkin explorations with our own individual pumpkins. If not, I buy a few small pumpkins and I put my students into groups to explore the same pumpkin. We measure the circumference with yarn and measure the height with cubes.
Then we predict and experiment to see if it sinks or floats. I like to repeat this experiment with a large pumpkin after experimenting with a small one. Students will often think the large pumpkin will sink, and then are shocked when it also floats!
I always bring in different pumpkin snacks to share as well. I usually bring in pumpkin seeds first and put them in a snack baggie. We use this recording sheet (found here) to lay out our seeds. We look at them closely and count them out.
Mostly because I love food, I grab a few different pumpkin treats from the grocery store. We taste them and then graph on our favorites!
And finally, we carve a pumpkin. I love watching my students' different reactions when they reach in and feel the pulp and seeds.
After we carve our pumpkin, we always do "how-to" writing about the process. We also do many or all of the activities in my Pumpkin Math and Science pack from my TpT shop.
Finally, we get creative with our pumpkins! We had a blast last year turning our pumpkins into our favorite story characters.
So that's what we do. Now go out and get yourself some pumpkins!