# Bouyant force in air on hollow object

I understand that the buoyant force is equal to the weight of the air displaced by the volume of the object. I also know that if we had a perfectly solid cube or a hollow cube closed on all sides so that the air inside the cube does not mix with air outside the cube, then the buoyant force will be equal to the weight of the air displaced by the volume of the cube.

However, my question is what will the buoyant force be when the cube is hollow and not covered on all sides, something like shown in this image ...

Will the buoyant force be equal to the weight of the air displaced by the volume of the cube, or will it be equal to the weight of the air displaced by the volume of the material used for making the cube.

Sorry if it is common sense or very simple, I am not the most intelligent person.

Thanks very much!

• Check my answer here: physics.stackexchange.com/q/142697 The buoyant force is proportional to the volume displaced, so in this case, it would be the volume of the 'plates' that build up your box Commented Oct 28, 2014 at 10:05