This is an ABC podcast.

A quick warning, this episode touches on the topic of suicide.

Take care while listening.

That's fizzing, okay.

Now it's smoking while fizzing.

I'm standing in a chemistry lab at Sydney University,

and I'm watching a small

pea-sized chunk of metal slowly disappear in a bowl of water.

It's bubbling away and it's moving around the surface of the water.

Yeah, just going to see if...

Like a Pac-Man.

It is a little bit like a Pac-Man.

Okay, so now it's just disappeared. Our little pebble is completely gone, I think?

It's not vanished. It's reacted.

Right, okay. More accurate.

The substance we've made react, not disappear, is the lightest metal on Earth.

It's got its origins at the very beginnings of our universe, and it's taken in the form of a pill by thousands of Australians every day.

Oh, and it can be flammable, so stand back.

So that was a relatively small amount.

If we had a much bigger chunk, would we see like an explosion or what would happen?

I've never seen an explosion, because I'm a really super safe chemist, but if we had a really large piece,

it would react much more vigorously, produce much more hydrogen, and yet it could set on fire.

...