Capacitor Bottle Model and Exponential Decay

An activity that can provide the central focus for a whole lesson of teaching on capacitors and exponential decay. Students explore and discuss the flow of water out of a hole in a bottle as an analogy for the discharge of a capacitor. They are then required to design an experiment and take measurements in order to determine whether this is exponential decay. The activity is fairly challenging and the teacher should actively engage with and support students as they work through it, especially if capacitors are the first context in which they have studied exponential decay experimentally. It can be completed with students working in groups and reviewing each others work to provide effective differentiation and peer learning. I have included teacher notes to explain the activity and the ways that you might help student engage successfully with it.