Ponderings

Every so often, my brain presents me with a problem that I must do my very best to solve. About a week ago, when I was in Halifax, I woke up with one thought on my mind: Could you give a goldfish a helium balloon for its birthday without the goldfish floating away?

I don't know why the thought appeared, but it did. And since then, I've been questioning others to see what they think. But the opinions of my friends, as lovely as they are, are nothing compared to the power of GOOGLE.

So, a quick search on t'internet provided me with this:
"A mole of air at STP, (for the sake of argument say it's all Nitrogen) will displace ~22.4 L (assuming it's close to ideal gas behavior) and have a mass of 28g. A mole of He will have a mass of 4g. This mass will be somewhat larger as you increase the pressure above atmosphere to fill the balloon. So you can lift ~ 1g/L, including the mass of the balloon; larger balloons should be more efficient if you can maintain a constant wall thickness because the balloon mass will increase like the area, and the lift increases with volume."


Jolly good! It sounds quite sciencey and believeable, and the result is about what other places suggest. So, I have 1 gram of lift per litre of helium. Apparently an averageish helium balloon has a diameter of 10 - 12 inches, which equates to around 10L of helium, give or take. So I can have 10 grams of goldfish, just, if I want it to be able to have its balloon and not float away. Which is sort of like having your cake and eating it, only not.

So, now for the weight of a goldfish.

Bless the google gods (or the 'goodles', if you will). They have given me this.

An averageish goldfish, I am informed, will be about 4 - 5 inches after its first year of life. Which, if we go to the magical calculator, means that it will just be able to be given a balloon for its first birthday as long as it's not an overinflated balloon or a small goldfish, and you have a weighty (but not too weighty!) ribbon to attach the two together. Hurrah!


I'm yet to find rates of goldfish growth, because everywhere is like "it depends". But once I find out, you can bet I won't make a silly mistake like giving a goldfish so many balloons for its birthday that I ensure its early demise.

Take THAT, science!

Incidentally, my googling also told me that a goldfish brain weighs 0.097 grams (size of goldfish was not specified - what type of scientists are these?!). So one helium balloon can lift about 100 goldfish brains. Innnnnteresting....