Experiment involving Coke and PC Cola

[anniw]

My teacher conducted an experiment in which he dispersed pop cans into a tub full of water. When he dispersed Pepsi cans and Coke cans (including diet) they both sank to the bottom. Contrastingly, when he dispersed the PC Cola can, it floated. I tried finding answers to why this happened but I wasn't successful. Does anyone have an explanation to this?

 

[rcgldr]

My teacher conducted an experiment in which he dispersed pop cans into a tub full of water. When he dispersed Pepsi cans and Coke cans (including diet) they both sank to the bottom. Contrastingly, when he dispersed the PC Cola can, it floated. I tried finding answers to why this happened but I wasn't successful. Does anyone have an explanation to this?

Assuming PC cola is sugar free, it's because artificial sweeteners require a very small amount of mass to equal the sweetness of sugar, so that the fluid weighs about the same as water. The small amount of gas in the cans results in enough bouyancy for the sugar free cans to float, in spite of the weight of the can. The sugar based drinks are denser than water, and they sink, because the small amount of gas doesn't compensate for the increased weight of the sugar water.

 

[arunbg]

It seems PC cola is less dense than water, whereas the other brands not. Does a can of PC cola weigh the same as other brands in same volume cans? If yes, then I guess PC cola reacts in some way chemically with water so as to make it less dense.

Edit: I thought when you meant disperse, you were talking about pouring the colas into the water.
If you meant whole cans, I think Jeff's explanation is right on the mark.

 

[Kurdt]

It could also depend on what material the can was made out of. Some companies still use steel and others use aluminium. If all the cans are the same material then there will be something that is in coke and pepsi drinks both diet and normal that makes them more dense than the PC cola. Perhaps PC cola doesn't fill their cans up as much etc.

 

[CraigD]

Putting entire sealed cans in is just a function of the density of the liquid in the cans. I would guess that the PC Cola is cheaper and simply has a higher percentage of water and less syrup in it.

CraigD, AMInstP
www.cymek.com

p.s. Lite Beer floats.

 

[rcgldr]

It seems PC cola is less dense than water

PC Cola plus the small amount of gas are less dense than water. PC cola will be slightly denser than water, but as mentioned, the small amount of gas is enough to compensate for the density of can and cola.

 

[Kurdt]

Putting entire sealed cans in is just a function of the density of the liquid in the cans.

I would have to disagree and say that the density of the whole can and liquid is what is important. The displaced water has to be able to support the weight of the can and the liquid inside.