Taken with a grain of salt

By Eric Pettifor

This week we’ll be considering the element known as sodium. What is sodium? Some
might say “Sodium is that which makes salt bad for us,” which would be a mis-characterization born of the fact that we get altogether more salt than we need, largely because of its ubiquity in processed foods.

In fact, we need sodium so much that, in the pre-processed-food-past, salt was highly valued. Our modern word salary is from the Latin salarium, thought to have been either a portion of a Roman soldier’s pay, or an allowance given for the purchase of this critical, life giving substance. Its importance persisted millenia later when the British in India controlled its collection and manufacture, providing tremendous symbolic value to Gandhi when he led his Salt March in 1930. He and his followers gathered salt in peaceful protest of the British law.

We need sodium in order to:

When geophysicist Dan Lathrop wanted a molten metal to slosh around in his 10 foot diameter metal sphere in emulation of the molten iron core of the Earth, he chose sodium because it melts at a much lower temperature than iron.


Wow. Aside from the fun factor, though, wouldn’t it be easier to study planetary magnetic fields using a computer model with virtual values more congruent with the real thing? Sodium isn’t iron, and Lathrop’s sphere, while big for a lab experiment, is tiny compared to an actual planet.

Computer models can’t capture all the complexity of the flow. The whole system likely feeds back on itself — the flowing metal creates a magnetic field, but that field can then exert forces on the iron, changing its flow. This, in turn, can change the field, which will change the flow.

NPR’s David Kestenbaum

So a great big, highly explosive sphere it is then. That’s right, one of the most exciting things about sodium is that it explodes really easily, just add water.

Or for really potentially deadly fun, how about adding some chlorine gas into the mix? Plus just a single drop of water to get the whole thing going…



Man, I should have been a scientist. But back when I was in school, they didn’t let us play with explosives or deadly gasses. About the most fun we had was mixing vinegar and baking soda. Oh well. At least I’m still alive today.

Of course, if you want explosions done big, no one but no one beats the American military.


So there you have it. Sodium: in small amounts critical to brain function, in slightly larger amounts a contributor to increased risk of heart attack, and in large amounts, with water, capable of blowing your head off. Use with caution.

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