We like mechanical calculators like slide rules, but we have to admit that we had not heard of the Ott Derivimeter that [Chris Staecker] shows us in a recent video. As the name implies, the derivimeter finds the derivative of a function. To do that, you have to plot the function on a piece of paper that the meter can measure.
If you forgot calculus or skipped it altogether, the derivative is the rate of change. If you plot, say, your car’s speed vs time, the parts where you accelerate or decelerate will have a larger derivative (either positive or negative, in the decelerate case). If you hold a steady speed, the derivative will be zero.
