How does a reverse-osmosis (RO) purifier turn salty water into drinking water?
Normally osmosis drives pure water toward the salty side.
Normally osmosis drives pure water toward the salty side. In reverse osmosis you apply a pressure GREATER than the solution's osmotic pressure on the salty side, forcing water molecules backward through a semipermeable membrane while the dissolved salts and impurities are left behind. Push hard enough to beat the osmotic pressure and clean water comes out the other side.
Key point
Apply pressure > osmotic pressure to push solvent backward through the membrane, leaving solutes behind.
Common mistake
thinking RO just filters like a sieve with tiny holes for salt.
Memory tip
reverse osmosis = overpower osmosis with pressure to squeeze out pure water.
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