Australia's Science Forum

We put a can of coke and a can of diet coke in a beaker of water, and they both float - the regular coke's supposed to sink. Is there something we're missing?

I did this a few years ago and it worked properly. Air bubbles under the can? Maybe try another can of normal coke?

definitely works....

also check the temp of the water it may be a factor. I'm assuming both cans were room temp?

We have tried this too with no success. I just assumed that the pictures I had seen were American or something because they have a different recipe (everyone I know who has been there says "Don't drink the coke!"). A teacher tried with bottles first, and my thought then was the air bubble was making it float but then the cans did too.

tried different cans, room temperature in tap water - all float
we using 200ml size; would that make a difference?

The ones we used were the regular 357ml, also at room temp.

we used full sized (375mL) cans. I think we used Coke v Coke Zero as well

hmmm... perhaps the water is too cold? What if you tried cold cans and room temp water? Our water comes out pretty cold, so might be worth adding some hot? I think we tried it last term so it would have been really cold then.

no coldies atm; just tried in hot tap water - same deal, both float
weighed 2 cans, about 14g difference