Catapults as a Culminating Task

In Grade 10 math we’re working towards our mastery of quadratics and problem solving, and are currently analyzing the trajectory of a pompom flung from a catapult as our culminating task for the course.

Each group of 4 students got a small sandwich bag with 10 popsicle sticks/tongue depressors, 3 elastics, a plastic spoon and a pompom. Each group also got some tape, a measuring tape, a print out of a target, and a work package to help them direct their learning and organize their information.

There were many different ways that groups designed their catapults. It is interesting to see how varied the trajectories were!

Groups came one at a time to the hallway to use the app “Visual Physics” to video their projectile.

The app lets you step through the video frame by frame and locate the position of the pompom. We used a white pompom to see it against our purple wall. It’s important to use a meter stick to add a calibration scale so our data can all be reasonable and comparable when it is exported.

The video and data points are then exported to a different app called “Graphical GW” to be analysed. We can select different ways to show the data. We chose a table and a graph, comparing the horizontal and vertical distances as x and y. We can apply a curve fit too which will provide an “a”, “b” and “c” value for the standard form equation.

We can see that the table will let us create an equation in vertex form, and we can calculate the “a” value and compare it to what we have from the curve fit. We can use the equations to calculate the x intercepts and predict where the pompom will hit the ground.

All seven groups got their catapults made and data collected today. Tomorrow we will work on the analysis and get some feedback and think of some good extension questions to tackle.

Our final step will be to give students a set of data, similar to what they used today, and have them repeat the process individually, and answer some extension questions.

Each time we work through this process, I try to refine what I do. Last year, prepackaging the materials was my improvement. This year it was to give them a target and measuring tape, and to scaffold the collection of data and analysis with a work package. Next year it will be to establish a “how to clean up” process, as with all the excitement we ended up with a lot of debris around the room!

As with a lot of these tasks, it is important to let go of the reins a little, and let students take control of their learning and own the task. Since we have worked in groups all term, we have broken down many barriers, and students are getting very good at helping each other and asking each other good questions. At this point in the year they have learned a lot and are getting quite confident with their skills, which is great to see.