Imagine a dry sponge sitting in a shallow puddle of water. The sponge is “zero concentration” of water. The puddle is “high concentration.” Water moves into the sponge until the sponge is just as wet as the puddle.
This is the universal rule of nature. Things want to balance out. Energy wants to be even. Sound fades into silence. And your favorite salad dressing will eventually stop separating if the ingredients have similar concentrations.
This is also why you should never put a freshwater fish in saltwater. The salt concentration outside the fish is much higher than inside. The fish’s body would desperately try to balance the salt levels by losing water, basically turning the fish into a salty raisin. Not nice.
The Pickle Crisis
Here is a story that made me smile. My friend Nick put a slice of pickle on a slice of white bread and left it for an hour. When he came back, the bread was soggy and the pickle was limp.
That bread had a lower salt concentration than the pickle brine. Water moved from the bread into the pickle to try and make the concentrations equal. The pickle “drank” the bread’s moisture.
So when you make a sandwich for lunch tomorrow, remember Nick’s pickle. You are watching osmosis in action. You are a mad scientist at the kitchen table.
