How does desalination work for kids

As the number of desalination plants worldwide continue to grow, so do concerns about developing new technology to power the plants. Currently, large-scale desalination efforts require a lot of energy to operate and often are high-maintenance affairs, thanks to lots of working parts like membranes that tend to foul frequently [source: Schirber ].

Costs are another concern: During the past five decades, public and private investment in developing desalination technology has reached more than a billion dollars worldwide. And even with the progress that's been made, the idea that desalination would do away with water scarcity is far from reality. And that's because it's still really, really expensive to plan, build and manage desalination plants [source: Water Science and Technology Board ]. Producing fresh water using reverse osmosis costs about one-third less than multistage flash, largely because of the costs of the thermal energy used by the latter method in the boiling process [source: Water Science and Technology Board ].

Unfortunately, both processes -- as with all desalination techniques -- create brine. This by-product of desalinated water contains high concentrations of salt and, when released back into a natural body of water, can cause damage to marine life. That's because brine, which is usually denser than the water into which it's released, settles atop low-lying sediment where it depletes surrounding waters of oxygen [source: University of Texas at Austin ].

These cost and environmental concerns are all part-and-parcel of the next round of improvements in desalination technology and processes.

Light-weight portable desalination devices are being developed by researchers in Korea and at the Massachusetts Institute of Technology. The units produce enough fresh water to support several people.

The process uses gravity -- simply pour saltwater into the top of the device -- to remove salt and other sediments using 1, filters [source: MIT ]. Like these solar-powered portable units, large-scale reverse osmosis plants, although still in the planning stages, could also greatly decrease desalination plants' reliance on fossil fuels.

In addition to government funding in the United States and abroad, private funding sources are beginning to pay attention to developing more efficient desalination efforts. One thing is certain: If the desalination process improves, it could have the potential to change entire water-poor regions for the better.

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Environmental Science. Earth Science. How Desalination Works. About 70 percent of the world is water, but so little can actually be used because most of it is salt water. Desalination at Work There's more than one way to separate salt from water , but nearly 90 percent of the time, only one of two methods are used: multistage flash and reverse osmosis [source: WorldPumps.

Desalination from Aristotle to the U. Scientists are using new technology to answer this question. In this video, we'll explore the pros and cons of desalination: the process of separating water and salt molecules from seawater to create drinking water.

Below are discussion questions you can use in the classroom in conjunction with this video to engage your students with this innovative technology.

Use this resource to ground your understanding before integrating this video into your lesson. Alternatively, allow your students to practice close reading of scientific texts by passing out the article and the empty version of the chart—let them do the work! Because the issues we're exploring in Flipside Science are complex, we've evaluated how the solution fares across three important dimensions: the environment, the economy, and society.

Weighing the Pros and Cons How do we assess the benefits and drawbacks of various solutions to a problem? To decide how one potential solution compares to another, we have to consider the pros and cons of each from many dimensions: environmental, social, cultural, and economic.

In this activity, students will work together to map out the strengths and limitations of potential solutions to some important water use and conservation issues.

While this video doesn't necessarily cover the following standards in depth, it is a compelling resource you can use to supplement your curriculum that does. Humans depend on water, and our need for this precious resource is growing alongside our population. How will we meet the needs of the future without harming the environment? The pores in the membranes are so tiny that salt, bacteria, viruses and other impurities are separated from the seawater. In essence they act like microscopic strainers.

About half of the water that enters the plant from the sea becomes fresh drinking water. The salt and other impurities removed from the sea water is then returned to the ocean via diffusers, which ensures it mixes quickly and prevents impacted the marine environment.

The desalinated water is then subject to further treatment to meet drinking water standards before it reaches our customers. Outside is best. We left our bowl in direct indoor sunlight for about five hours and were only able to collect about two tablespoons of water during that time. It should taste fresh! In fact, our water tasted much better than our filtered water usually does. The process we used to desalinate the water is also how water distillation works, which is an effective water purifier.

Monkey was not convinced that this water science for kids activity would produce freshwater until she drank the desalinized water we made.

She was surprised at how effective it was!