Whirled Peas: A Case Study in Legume Buoyancy

November 13, 2008 By: erik Category: Food, Geeky, Musings, Science, Videos, Weird 775 views

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Whirled PeasI make a lot of salads, more in summer months, but probably at least 50 per year. I also have been known to, on occasion, blogaboutsalads. One of our favorite salad ingredients is peas. We buy them frozen in a bag, pour a few into a glass, and add warm water to thaw them. One of the things that puzzles and fascinates me every time I thaw peas is that 20% of them float. And it’s roughly the same percentage every time. Why would this be? Do the sinking peas have a skin breach that is letting in water? Do the floating peas contain air, or is it some property of the cell tissue? Is the freezing and thawing process relevant to this phenomenon? Do fresh peas float?

Naturally I made a video to demonstrate this phenomenon. The stirring allows the floaters and the sinkers to segregate.

You can see why I don’t get much sleep at night.

  • Paul

    Those are the young, sweet peas on top. As peas convert sugar into starch, the specific gravity of the peas increases, since starch is more dense than sugar. Want a sweeter salad? Throw twice as many peas into the water, then throw the sinkers to the birds.

    And thanks for aiming a question at one of my knowledge bases. I did a science fair project on specific gravity 50 years ago.

  • I checked the sound on my computer twice figuring I must be missing the whirled peas sound track . . .

  • I didn’t put a soundtrack on this one, unfortunately. I guess Lennon’s Give Peace a Chance or Cat Steven’s Peace Train might have worked. I might rectify that.

  • You don’t sleep at night thinking about peas? I think there are a lot more interesting things that could keep you awake…but to each his own. 😉 Tell me, do you run your hands through the legumes at the store? Now that’s soothing… 🙂

  • Posts like this are what the Internet was made for.

  • aquariumdrinker

    Had a friend once, a dedicated Allman Brothers fan, who wanted to showcase both her fanship and her commitment to world peace by having her license plate communicate “Peach for Peace”. Unfortunately, NC would only allow 8 characters, so she ended up with PCH4PEAS. Before she went down to the DMV, I asked whether she was sure people would understand. She said she figured they would because of the classic “whirled peas” joke. I think she was overoptimistic.

    I can’t be too judgmental, though, as I supported my accountant wife in getting a license plate that said “I DO #S”, without it ever occuring to me that people might read that as “I do pounds”, “I do hash” or “I do number five”. (The last of these suggests some transdimensional bodily function of unspeakable horror (which is now officially what I will suggest to people as a band name — “Transdimensional Bodily Function of Unspeakable Horror” (which makes me wonder whether there will ever be a license plate that says “TBFUH4PEAS”)).)

  • What a fantastic comment thread!

    Paul: Thank you for clearing that up. I will do a taste test next time to verify your hypothesis.

    Betsy: Soundtrack added. Much better now. It’s hard not to hear the word “peas” in the song.

    Theresa: Remind me never to buy garbanzos from the open baskets in Pamplona. “To each his own,” indeed.

    Simon: I agree.

    Aquariumdrinker: Gah! I don’t feel so well. I think I need to go take a big fat TBFUH.

  • Excellent musical choice. You certainly are a responsive blogger.