The process of osmosis is a fascinating natural phenomenon in which pure water migrates through seemingly impermeable cell walls to dilute high concentrations of dissolved substances. Space scientists have been able to synthesize such "walls" and, in reverse, use water pressure to separate dissolved substances from the water. This has developed a filtration process that removes all conceivable contaminants in water extremely effectively. But how exactly do water filters work using this process, and when is such a filter worthwhile for me...?