Today we did the Vroom Vroom lab designed by Fawn. Basically, each student got a little pull back car and took data on the relationship between pulling back the car and how far the car would travel. The students entered the data into Desmos and played with the sliders on a linear equation to find a line of fit. Then they had to predict how far to pull it back to hit different distances. The winner was the person who got closest to that distance. We also got into a discussion on when the models do and do not work. At a certain pull back distance the little cars would do a circle and shoot off in weird ways, or not go at all.
I used a great template designed by Mr Orr and made a few adjustments to the distances based on the cars I had. I wanted one to be obtainable and another to cause more problems for at least some of the students. The biggest issue was the lack of Desmos enabled devices (we had 2 for the class to share), but that turned into a positive when early finishers turned into mentors helping their classmates enter and predict.
The students seemed to enjoy it and the math talk it produced was fantastic. They became attached to the cars, giving them names and makes. They also found reasons to love their car. One went the farthest, one was very predictable, etc.