Here are three situations involving the relative concentrations of solutions across a semi-permeable membrane. You can cut them out, put sets into baggies, and (optional) tape them to playing cards to make them durable. Have students do card-sorting activities:
1. Match Picture-Name-Arrow-Description for each type of membrane situation
2. Use the cards to explain (with a partner's help) what's happening in current lab / demo
I had students sort / make pictures with their card sets in class to solidify the day's lecture. I put this document on Edmodo for them, also, so they could practice at home with their own set. I'll use some of the same pictures on their quiz.
This is the third of three card-sorting sets we used for Membrane Transport this year.