Learning-By-Doing leaflets in issue 86

In the first section on pressure, students learn some important principles about water and air pressure. They will need to know these principles in order to understand how different types of water pumps work. In the second section, students learn about different sources of water including ground water, which can be tapped into by wells, and run-off water, which can be collected in water tanks or behind dams. Then, they learn about various kinds of water-lifting devices, and finally, about various appropriate technologies for insuring safe water supplies.