Conversation:

A friend of mine recently filled up a range of water balloons and left them outside overnight to freeze, so that she could use them for outdoor decorations.

This is the result:

https://twitter.com/ladycrafthole/status/278803560492318720/photo/1


As you can see, all the balloons froze except the red one. They were all filled at the same time with water from the tap, and they were all left outside, in the same place, at the same time.

So, why didn't the red water balloon freeze?

I reckon the butler was responsible.

Thanks Icy, I knew we could rely on you for a detailed physics explanation.

What colour were the other balloons? And how light (in brightness) were they? (I can't follow your link)

A pink, light purple, green, blue, yellow and orange. All were quite light in colour.

As she left them outside 'overnight' - and I assume your nights are dark - I don't think the color had anything to do with it. Unless the specific color that was used did something to the structure of the rubber - maybe.

... did it not freeze at all or was it just not fully frozen?
And there's some frost on it, was it wet when it was put in the garden?

She did them all at the same time, so if one was wet I'm guessing more would be.

Maybe she spilled water on it while filling it but didn't do that with the others. But I may be completely wrong here. Frost/snow insulates but I'm not sure how much there has to be to make a difference.
Maybe the red one was the first she filled and the water was still warm from alst time the tap was used? That could also be a reason for the frost, I guess.

Apparently the water warm when they were all filled, she doesn't think she spilled any.

She did some more balloons last night, and those that didn't freeze also had frost on them.

red's hot innit

There are a lot of variables...

The weight of the rubber in each balloon and the diameter of the balloon when inflated (meaning that the more you inflate the balloon the thinner the layer of rubber becomes - thus providing less insulation.

Are the chemicals used to colour the balloons all identical - could something be leaching into the water and acting as an anti-freeze?

Oh, and...

>>>She did some more balloons last night, and those that didn't freeze also had frost on them.

Are we sure that this phrase hasn't gotten its cause and effect inversed?

Could it be possible that the frost itself is having an impact on the water inside and that the phrase should read...

"...those that had frost on them didn't freeze".

I'm going to buy some balloons today and experiment meself.

Not sure if everyone can see the photo or not, I know Gnomon said he had difficulty in doing so.

The balloons all came from the same pack, so I'd assume that they're all the same except for the colouring. They were also all filled to the same size.

But they look like they have different sizes. Maybe the red one was leaking?

It does look slightly smaller, but I think that might be an optical illusion.

Maybe it's further away.

Careful now

FB

Water expands when it freezes. Since the red balloon didn't freeze, it didn't expand.