It all started with a trip to the grocery store where I noticed a giant pumpkin on display & a prize of $50 in gift certificates if you could guess the weight of the pumpkin:

I went back a couple of days later to take some measurements of the giant pumpkin, bought 4 smaller pumpkins of varying sizes & we were on our way!

**Day 1**

**Act 1**

*What do you know / notice?*

*What do you wonder?*

*Estimate the weight of the pumpkin in pounds:*

I passed around a 1lb bag of barley that all the student We start with a guess that’s too high (but not silly like 5000 lbs), then too low (but not silly like 1 lb). Then they make their best estimate:

Then I have them do a turn & talk with their group (visibly random groups of 3) to discuss what they need to a) measure, b) Google c) calculate in order to solve this problem.

Students made a prediction about which characteristic of the pumpkin the weight would depend on most:

**Act 2:Â **

I revealed some measurements I’d taken of the giant pumpkin:

We had 4 pumpkins of various sizes at stations around the room with a scale to measure weight and rulers & measuring tapes. Groups were sent to their vertical non-permanent surfaces to begin collecting & recording data about any measurements they thought they might need for the pumpkins to help predict the giant’s weight:

Groups recorded measurements and started calculations for volume, etc. in order predict the giant pumpkin’s weight:

At this point we hit the end of the class period. Some groups had some volume calculations but none of them had got to (or really thought of) creating a table or a graph of weight depending on another variable to make a prediction.

**Day 2**

I was away this day & so students had the period to do some independent practice on Volume & Surface area word problems on Khan Academy.

**Day 3**

I wanted students to graph weight VS diameter, weight VS surface area, & weight VS volume. So I created a Desmos Activity to walk them through that process:

I provided students with the raw data they would need (as they had already worked on these types of SA & Volume calculations the previous period – today’s learning goal was all about the linear & quadratic relations between different variables):

They found the line of best fit and quadratic curve of best fit. We had a class discussion about which one fit the data better … quadratic!

They they used that curve to predict the weight of the giant pumpkin based on diameter:

I walked them through that first set of tasks step by step as a whole class making sure everyone understood. Then I turned the Desmos Activity to student-paced mode & let them continue the same graphing tasks for weight VS surface area & then volume (although many of my students gave up working on it once I was no longer leading the class through the activity slide by slide).

Each student had filled out an entry slip for the pumpkin contest at the end of day 1, and I allowed them to adjust their entry if they wanted based on today’s work. I then dropped off all of their entries after school:

**Day 4**

Started class by revealing the weight of the giant pumpkin.

DRUM ROLL PLEASE . . . **166 pounds**!!!

I then presented them with a the 3 models we created, each showing the giant pumpkin’s actual weight as an orange dot & asked which model was the best predictor for the giant pumpkin:

I finished by having the students drag dots to any Math from our course that we used over the last few days with this activity:

Students had the rest of the period to do some individual practice on “Graphing linear functions word problems” on Khan Academy.

My folder with everything for this activity can be found here. The unassociated files are the Pear Deck interactive slide decks.

â€“ Laura Wheeler (Teacher @ Ridgemont High School, OCDSB; Ottawa, ON)