This unit explains the water cycle through the endless journey of water around the planet. It makes students understand that water is always travelling and transforming itself; makes them aware of the fact that only a very small part of the planet's water is safe to drink; and makes them understand that the water they drink today is the same that a dinosaur once drank! The additional resources stimulate the students' manual, cognitive and creative skills, and favour learning through reasoning and experimentation, that directly involves the student in the acquisition of new knowledge.