Throwing sodium into a pond

I don’t recall much of my high school chemistry classes back in Sri Lanka. Our teacher was a nice old man who enjoyed telling us the history of chemistry and stories about the chemists of long ago rather than about modern chemistry. But he was a believer in experimentation and demonstrations and one that I remember was when he would cut a small piece of solid sodium and drop it into a beaker. It was fun to see the piece foaming and rushing around the container.

Solid sodium is highly dangerous and can cause severe burns so he would not let us handle it but only do this himself with us watching. I am not sure whether with our increased concern for safety in science classes, this kind of demonstration would even be allowed these days, just as the way we would play with liquid mercury would now horrify people.

But some people have managed to get a large chuck of sodium and recorded what happens when they throw it into a pond, creating essentially a scaled-up version of that demonstration.


  1. says

    That wasn’t much more than you’d get from an M-80. Perchlorate and aluminum. *yawn*

    When I was in college we partially emptied a pond that was a bit smaller than that, using a large amount of flash powder. I mean _large_.

    Stupid kid needs a steadicam; you can get inexpensive ones for $100 ffs.

  2. Trebuchet says

    @1: I shall have to remember that next time we visit my wife’s relatives in central Washington, since I always make it a point to drive through the Grand Coulee.

    I wonder what they were using the sodium for in the war effort? Something at Hanford, I’d have to suspect, since it’s not too far away.

  3. says

    @Trebuchet #3 -- if you’re driving through grand coulee, seriously, get a $50 steadicam instead of a tripod. You can shoot video out a moving car’s window and it’ll look like it was shot by industrial light and magic (just keep the wind off the camera or you’ll have a whirlibird)

  4. Bob Dowling says

    And the fish and plants in that pond?

    Once the alkaline product has diffused across the whole body of water I expect it will make a negligible difference, but near where they threw the sodium in there are going to be dead fish in toxic water.

  5. Trebuchet says

    @6: That’s the reason for the selection of the lake in the link in #1. They’re already alkaline in the lower Grand Coulee. Which has utterly awesome geology, I highly recommend it.

  6. coragyps says

    I am told that 500 grams of sodium beneath a centimeter of ice on the Olentangy River makes a nice late-night pop, too. That’s what I heard….

  7. dean says

    “… just as the way we would play with liquid mercury would now horrify people.”

    You mean like this?

  8. wilsim says

    My high school chemistry teacher did something similar to this. He took the class down to the courtyard near shop/woodworking class and put about a square inch of magnesium into a 4 quart glass bowl of water. I don’t know if he had done the experiment before, or if he was ambitious, or just miscalculated what the reaction would be from a chunk so big…

    The resulting explosion was spectacularly loud (it set off a few car alarms nearby), the glass bowl shattered into millions of tiny pieces -- luckily the most of the glass didn’t travel upward but at a shallow angle to the ground. A couple of us had minor cuts on our legs from the glass shards.

    Mr. Carlsen exclaimed his dismay that his bowl was destroyed and that he wouldn’t be able to repeat the experience for his afternoon class.

    Chemistry is fun.

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