Desmos, which you may know as that awesome and free online graphing calculator, is now producing awesome and free lessons. They refer to their lessons as, “Hand-crafted classroom activities. Designed by teachers. Built with love by Desmos.” These activities are computer based, and provide the classroom teacher with all kinds of formative data about how the class is progressing through the lesson.
Water line has students create height vs. time graphs representing the height of water in various different shaped containers. Work your way through it. It’s kind of fun.