Does Aluminum float in Mercury?

Will aluminium float in mercury? My father says it will, I’m not so sure. He say relative density has something to do with it. I have tried to find an answer to this, but have been frustrated.

I don’t have time to properly research this right now, but I’m pretty sure the answer to this question is: drumroll yes!

IIRC, mercury is much heavier than aluminum… so the aluminum would float…

Yes. From, the desities at room temperature are

Aluminum: 2.702 g/cm[sup]3[/sup]
Mercury: 13.456 g/cm[sup]3[/sup]

so it’ll float pretty well.

Yes, but has anyone actually ever tried it?

Somewhere there is a picture of a one ton block of granite floating in a pool of mercury.

Zen, any idea where that pix is? I’d like to see that!

In a chemistry class I had occasion to try this. I can personally verify that yes, an aluminum bar will float in mercury. Unfortunately, the mercury bonded to the aluminum bar’s surface, and the teacher was pissed because he had to throw out his aluminum piece, it was contaminated.

Yes, aluminium will float in mercury. Mercury is relatively dense so many metals will float in it - iron for example, or even lead.

However, mercury reacts with aluminium in bad ways - it breaks down the protective oxide layer on aluminium’s surface and leads to rapid corrosion. This is why mercury thermometers and barometers aren’t allowed on commercial flights - spill the mercury and it’ll eat through your airframe.

Please provide a reference for that last statement about mercury thermometers and barometers.

Please don’t be tempted to try to float any gold in Mercury. It won’t as it is denser, but more importantly, the mercury will form an amalgam and ruin the appearance of the piece.

Cool fact of the Day August 19, 1999

Hazmat shipment indicators (FAA web site)

Not exactly rock-solid, but it has the patina of truth.

One thing I had as a kid was a magic set with two “coins” (actually “slugs”), that looked alike.

One was aluminum, and would sink in water.
The ringer was zinc, which would float, provided you were careful not to break the surface tension.

So you’d make a big show out of how hard it was to float the zinc one and how careful you could be to float it.
Then switch and the other guy can never repeat your trick.

DSYoungEsq: "Please provide a reference for that last statement about mercury thermometers and barometers."


There’s an anecdote about airline staff trying to prevent a passenger from taking an EMPTY mercury barometer on board because barometers were on their prohibited list!

Hey, they used to float fresnel lenses in mercury for lighthouses, why not a chunk of aluminum?

(Yes, I understand density vs. mass, but I couldn’t ignore a chance to link to the coolest GQ ever asked. Rodd Hill, if you read this, how is this one going?)