How can you tell if a cell is alive?

Normally, when a cell dies, the outside morphology changes, in other words, the cell looks different. For example, if you are growing cells that attach to a plate, when they die they are not able to attach to the bottom of the plate anymore, and they will appear floating in the medium. I am not sure of what kind of cells you are studying; if you told us it would help as to suggest ways of distinguish between live/dead cells.

i believe you meant to say air rather than hair so the answer is below ")

the dead sea, the lowest place on earth at 430 metres (1,410 ft) below sea level, has a correspondingly high typical atmospheric pressure of 1065 hpa.