Water, Water Everywhere!

Narration: Troy Cline

Transcript:

Transcripts of Water Water Everywhere_Final.mov Music Title: Water, Water Everywhere Water is all around us, and it's importance to nearly every process on earth cannot be underestimated. The process by which water moves around the Earth, from the ocean to the atmosphere to It is the only compound that can found naturally as a liquid, gas, and solid. The process by which water moves around the Earth, from the ocean to the atmosphere to the land, and back to the ocean, is called the water cycle. Water regulates climate, storing heat during the day and releasing it at night, and carries heat from the tropics to the poles, by sea and by air. Let's follow a single molecule of water, beginning in the ocean, through the paths it might take before eventually winding up right where it started - back in the big blue sea. The fuel for this journey will be provided by our planet's prime energy source: the sun. During the day, the sun heats up the air and ocean surface, causing water molecules to evaporate. Evaporation occurs when a liquid molecule of water escapes into the air as a gas. This scientific visualization shows how water evaporation, indicated in turquoise, is driven by the energy of the sun. Notice how the rate of evaporation pulses over land: it speeds up during the day and almost disappears at night. Over the ocean, evaporation appears to remain constant, both day and night. Water in the air in gas form is known as water vapor. The molecule is now fresh water, having left the ocean salt and other particles behind. [Paula Bontempi] The water evaporates and goes into the atmosphere, and then it doesn't necessarily just turn around and fall as rain or snow. [Narrator] Condensation is the process by which water vapor molecules cool, stick together, and become liquid again in cloud formation. This often happens high in the atmosphere where the temperature is much lower than it is near the surface. [Paula Bontempi] What happens in the atmosphere is, just like we have currents in the ocean, we have winds in the atmosphere that actually, to some extent, drive what goes on in the ocean currents. Materials in the atmosphere can travel a great distance, sometimes a quarter of a way around the world, just until they get to the point where they actually turn into rain or snow and thereby fall back to the ocean or fall back to the land. This is called precipitation. precipitation. If the water molecule falls on the land as snow, it may be stored for a very long period of time in a polar ice sheet or mountain glacier, depending on climate conditions. [Matt Rodell] when rain falls or the snow melts, typically the next place it goes, it infiltrates the soil. So soil is not soli It's not like a rock, there are pore spaces that can be filled with water and typically there is a certain amount of water in the soil at all times. If soil was completely dry, plants wouldn't be able to grow. [Narrator] If soil becomes saturated, any additional rainfall will collect in puddles and streams. Soil water that percolates deep enough will help to recharge an aquifer. [Matt Rodell] An aquifer is any underground geologic formation that stores water so it’s typically either rock with a lot of cracks or it's sandy layer, sand has a lot of pore space in it. and can store a lot of water. [Narrator] The water molecule might remain in an aquifer for more than a million years. More likely, it would help to replenish a which would feed into lakes and rivers. Eventually, the water molecule will return to where it started: the ocean. [music] People also have a role in the water cycle. By pumping water out of the ground for irrigation, cutting down forests for development and building roads and other concrete surfaces that lead to runoff, people can have a serious impact on the path a water molecule takes. [Matt Rodell] The most obvious way that people affect the water cycle are the ways that we control the water after it’s fallen on the land surface as rain or melts as snow…But we have put in dams and rivers to hold this water. We’ve also pumped water out and use that. So it's these water resources, as we call them, are really us taking a natural part of the water cycle and using it to our beneift. [Narrator] The water cycle also affects and is affected by climate variations. [Matt Rodell] The water cycle is one of the ways we will feel any changes in climate. So climate changes will feed back to water cycle changes, how much precipitation an area the frequency of droughts and floods and this sort of thing. [Narrator] The water cycle is the adventurous journey that water takes through the oceans, atmosphere, and land, driven by the sun. Improving our understanding of the water cycle and how it is changing will be critical for future decisions related to water management, agriculture, natural resources, and climate change.