Offering an activity-based introduction to geography, this series introduces concepts gradually and simply, and supports them with activities which aim to be both easy and enjoyable - from building a gushing geyser and making a sundial to designing a Treasure Island map. Panel boxes provide real-life analogies, such as showing how toffee sets hard to illustrate how lava turns to rock. Focusing on rivers and oceans, this book starts with a description of the different forms of water in the world, and introduces the water cycle. Among the specific topics covered are the various stages in the life of a river, with a feature page on the Nile; the currents, waves and tides of oceans and seas; underground rivers; lakes; and water pollution. The activities include measuring the speed of a river's current and making a water filter.