Balloon quality slogan

The mass of the object has nothing to do with the temperature change, so the mass of the balloon remains the same when the temperature rises.

② According to the form

The mass of the object has nothing to do with the temperature change, so the mass of the balloon remains the same when the temperature rises.

② According to the formula ρ= m V, when the mass of hydrogen is constant, the balloon volume increases and the density decreases.

(3) The balloon expands in volume under sunlight, that is, the volume of air discharged increases. According to the formula F float = ρ air gV, the air density remains unchanged, and the volume of the discharged air increases, so the buoyancy of the discharged air increases.

So the answer is:

Constant; Reduce; Increase.