Would the same helium filled balloon float higher on a sunny summer day or a cloudy winter day?
On a cloudy winter day.Because the balloon will sink more in a rare(less dense) medium than a dense medium.In summer, the warm air rises and expands.This makes the air less dense and the balloon will sink more resulting in a lower height. On the other hand,on a cloudy winter day,the the air temperature will be less and so the air will be cold.This air will be denser and the balloon will not sink much and float at a higher level.
