balloon question

[ytrewq]

school year 7 science question. If I filled two identical balloons with the same amount of gas, one with helium and one with air from the lungs at first the hellium balloon would float and the air filled would not float but they would look the same. What would they look like after two nights? Do hellium balloons go down quicker because their molecules are smaller?

[squarebear]

Yes, the helium molecules are smaller and will pass easier through the balloon skin. This is why many helium balloons are made out of metal foil.

[gen2]

If this is homework, try to use the word 'Diffuse' or 'Diffusion' in your answer.