Weigh balloons a negative weight

Why does a helium balloon fly

Unfortunately, your answer is wrong.
The weight of the balloon must be less than the buoyancy force for a balloon to rise.

Since helium is lighter than air, the weight of the helium balloon is smaller than the buoyancy and the balloon rises.

Back to our example:

The balloon with a volume of 5 liters experiences a buoyancy of 0.064 Newtons.
5 liters of helium have a mass of about 0.9 g, which corresponds to 0.0009 kg. To this we have to add the mass of the rubber skin of the balloon. This weighs about 5g. The balloon thus has a total mass of 0.0059 kg and a weight (F = m * g) of approximately 0.058 Newtons. As you can see from our example, the buoyancy force (0.064 N) is greater than the weight force (0.058 N).

As the name suggests, a balloon is filled with air. The weight of the displaced air volume and the weight of the air in the balloon are therefore equal. It follows that the buoyancy force and weight of the air in the balloon are equal. But here too we have to add the mass of the rubber skin of the balloon to the mass of the air in the balloon, which is why the weight of the balloon increases. Thus, the weight of the balloon is ultimately greater than the buoyancy. The balloon falls to the ground.