ShmoopTube

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[Dino and Coop singing]

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Raisins: you either love them, or hate them.

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And if you hate them, keep it to yourself. [Raisins in the trash]

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Raisins have feelings, too ya know.

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But one thing raisins are good for is experimentation.

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So the next time you encounter one of these little guys, try this: [Raisin jumping in front of some test tubes]

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Put it in a bowl.

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Fill the bowl with water.

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Watch the raisin balloon up before your eyes. [The raisin swells]

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Will it taste like a grape?

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No.

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This isn't Hogwarts.

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C'mon. It's still a raisin.

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But it is a pretty neat example of a process called osmosis.

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Osmosis is the movement of water from a lower concentration to a higher concentration. [Coop pointing at a blackboard]

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So let's go back to our raisin.

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Here's the raisin...

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…and here's the water.

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The water is simply hanging out around the raisin.

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What determines if the water will go into the raisin is how much “solute” is present. [Arrows showing the flow of water]

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Solute just means any sort of substance dissolved into water. [Dino pointing at a blackboard]

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Like when your dad puts a million sugar packets into his morning coffee. [Teaspoon of sugar going into coffee]

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That sugar is a solute!

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When something is plunged in water, the water molecules pass through cell membranes from

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an area of low solute concentration into an area of high solute concentration.

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The water moved into the raisin, since it had more solute, and it swells the raisin [Water molecules shown in the raisin]

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up, making it bigger.

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That's osmosis.

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And guess what?

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Osmosis is used by plants all the time.

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They use it to take in water for themselves. [Plants next to a stream]

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How selfish.

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Anyway, if you've ever seen a dehydrated plant before, the stem might look all floppy and weak. [Plant drooping]

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Water that plant, however, and osmosis occurs, allowing the water to move into the stem, [Water going into the plant stem]

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stiffening it up.

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That's osmosis, too.

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Animal cells can also use osmosis – but there's a risk involved. [Chickens]

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If too much water moves into the cell, that cell can burst, just like a water balloon

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you left under the faucet for too long.

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In cells, this is called “lysis.” [Water balloon explodes in the sink]

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So if you take a cell with some water and solute in it...

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…then place it into a hypotonic solution – which just means a solution that has less

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solute and more water than that cell –

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…then the water will move into the cell, increasing the pressure. [The cell expanding]

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However, if you take the same cell and instead put it into a hypertonic solution – which

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means a solution with more solute and less water...

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Then the water will move out of the cell, leading to shrinking, or plasmolysis. [The cell gets smaller]

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Sounds like some sort of alien technology, huh? [People running away from a laser gun]

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Plasmolysis powered blaster pistols… [Aliens holding the pistols]

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Anyway, you might think this is all a bunch of scientific nonsense with no real world

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application, but consider this…

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What do people do when they drop their iPhone into the toilet? [Phone falls in and turns off]

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Well, after being totally grossed out, they usually fish it out and then place it into

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a bag of rice, drawing the water out and saving their phone from imminent death. [Water molecules leaving the phone]

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That's right, a cell phone saved, all thanks to Captain Osmosis.

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Which even we'll admit is probably not the coolest superhero name in the world. [Guy wearing a mask and a shirt with a big O on it]

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At least it's better than Captain Rice Bag… [Guy wearing a shirt with a big R on it]

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