When one looks around at the world and sees all the water on the earth and watches all the rain that falls from the sky, it is easy to believe that there is a constant supply of water for us. However, this isn’t the case. The earth has only a limited amount of water, and it is recycled over and over again in a process called the water cycle, or hydrologic cycle. The water that is present on the earth today has been here for millions of years. It goes through processes of evaporation, precipitation, and percolation. Sometimes the water will be present in a liquid state, sometimes solid, and sometimes gaseous, as molecules rise from the oceans up to the clouds.The process seems simple, but it is an amazing procedure that has many steps and independent variables. Water falls to the earth as rain, snow, hail, or sleet. When it completes its journey to the earth, it may find a home in the rivers and lakes. It may lie on the ground as snow, or it may freeze to form glaciers or frozen lakes or ponds. It may lie in the rock beds and percolate; it may flow freely, changing the look of the land over which is runs. Eventually the water evaporates, the air drawing molecules of water up to the clouds. When the clouds become heavy, the rain or snow falls once again. Through these and other processes, the same water is used on the earth over and over again.Following is an extensive list of sites available on the water cycle. There are interactive games and quizzes. There are laboratories, activities, and WebQuests to explore. So, come on in and explore the recycling effects of the water cycle.The Water Cycle Song
