[umgud]

We used to have sticks of sodium metal in our lab at school. It came packed in oil. It was a soft material we could shave pieces from and throw in a tub of water, which erupted really greatly depending on the size of the sodium metal piece.

[trebb]

Yep - a science teacher dropped a BB-sized piece of Sodium into an aquarium set up for the purpose and it took off zooming around when it hit the water...

[Hootowl99]

Yep, elemental sodium does blow up good when exposed to water including just the humidity in air. A chemist I worked with was transferring a chunk of sodium from a gallon can of diesel to the airlock of an inert gas glove box when it squirted from the forceps like a watermelon seed. It headed straight for the lab sink. The chemist took off running, very prudent, and the sodium chunk made a perfect bulls eye into the sink drain. The explosion blew out the sink and trashed the cabinet.

[Western Phil]

I think this experiment has been done before, although the only evidence I have seen was a letter over 50 years ago. Supposedly my brother & friends confiscated a significant quantity of sodium, sealed it in a canning jar, floated it out on a pond and triggered it with a 22 rifle shot to the jar. Would have liked to seen that, but was too young to tag along.