Learning about rationality behind African technology is a way to learn about how Sustainability can be achieved. To study water lifting incorporates to understand how a rubber bag is made and used. Dialogue with its users may reveal more if the student suggest an alternative for the traditional technology. When users like to test such an alternative, even more reasons behind the actual situation can be disclosed.
Such alternatives could be the traditional rubber bag, a scalable template for a rubber bag and a pulley and a tripod over a well.