Water is essential to sustain human life. Water is used for drinking, cooking, bathing, and growing food. This liquid covers 70% of the surface of our planet and is found in rivers, rain, glaciers, clouds, oceans, lakes, underground aquifers, snow, and even as dewdrops on the morning grass. Interestingly, it doesn't stay in one form for too long. Snow melts, water vapour in the sky falls to Earth as rain, rivers flow into the ocean, groundwater bubbles up to the surface through springs and geysers, and lakes constantly lose water into the atmosphere. This process of water changing from one form to another as it moves through the Earth's environmental systems is called the "water cycle". The water cycle shows the continuous movement of water within the Earth and atmosphere. It works by using the energy of the sun to exchange water from the earth's surface to the atmosphere and back again in a continuous cycle, whether liquid, solid or gas. It's always happening, all around us, all the time.