u/Dr0110111001101111

Just barely squeaked in but I’ll take it!

I initially made this app to use in an introductory activity I do with my calculus classes in September. I roll a ball down an inclined plane, we measure the position of the ball over time, and talk about velocity. They already know about average velocity, but the logger suggests the ball has an instantaneous velocity. But the average velocity calculation fails, and so we naturally start to see the motivation for limits. I used to do this with a Vernier motion tracker, but the results kind of sucked and that thing is crazy expensive.

But then I realized I can also use it to illustrate some key ideas about critical numbers- the graph view shows the velocity reaches zero at minimum and maximum values in position.

And then I added a “matching game” for my younger kids. It overlays a piece wise linear graph. One student points it at another and tells the target student how to move in order to reproduce the overlaid graph.

I’m really excited to find even more ways to use it in my classes, but I’m also excited it to share it with other teachers and know what you think of it. Check it out and let me know!

x of t

Video of how it works

Oh, but heads up: you’ll need to update to iOS 26.4 or later. And like I mentioned above, it will only work properly on “Pro” iPhone/iPads because they are the only ones that come with the necessary sensor.