# Potential energy of hydrogen balloon

1. Oct 11, 2011

### Himal kharel

Hydrogen balloon naturally moves from low altitude to high altitude in earth's atmosphere. Any object moves from higher to lower potential. So can we call low altitude high potential region?

2. Oct 11, 2011

### sankalpmittal

No , High potential region is always considered to be the region of high altitude. If object moves higher than its original altitude , then the object is said to be at higher potential.

You just cannot say that Mt. Everest is higher than Mt. K2 , so Mt. Everest is a high altitude potential region than Mt. K2. It is always with respect to something changing location. Yet , you can say Mt. Everest is a higher altitude region than Mt. K2.

3. Oct 11, 2011

### Drakkith

Staff Emeritus
I think in the case of a balloon the potential energy is less as it rises. For something like a rock it would be more potential as you raise it higher.

4. Oct 11, 2011

### Staff: Mentor

5. Oct 11, 2011

### Himal kharel

Consider two points in earths atmosphere A(high altitude) and B(low altitude). In order to take stone from B to A we need to do some work which is stored as potential energy in the stone. So point A is high potential region for objects that have natural tendency to fall.
But for hydrogen balloon we have to do work in order to take it from point A to B. Similarly work done is stored as potential energy. So point B is at high potential than A.
If anything is wrong with my explanation please correct it.

Thanks

6. Oct 11, 2011

### Drakkith

Staff Emeritus
It looks good to me, but I can't be 100% sure.

7. Oct 11, 2011

### Astronuc

Staff Emeritus
It would help if one were to distinguish between gravitational potential and bouyancy. As a hydrogen balloon rises and the atmosphere thins, there is less difference between the effective density of the hydrogen balloon and that of the atmosphere.

8. Oct 12, 2011

### Staff: Mentor

For completeness, you should split the problem into the two different types of potential energy you are seeing: one due to gravity alone, the other due to buoyancy. Both apply to the rock as well, you're just ignoring the buoyancy of the rock.