1. The problem statement, all variables and given/known data For a solar tower compare the total force on the air column in the tower (i) by calculating the pressure at its bottom and top (ii) from Archimedes’ Law. Hint: there is a temperature difference between top and bottom of the tower. I have to estimate height, temperature difference and such. 3. The attempt at a solution According to Archimedes' law the force is just F = g * A * h * (ρ2 - ρ1) with g = 9.81 N/kg, A the area of the tower, h the height of the tower and (ρ2 - ρ1) the difference in air density between top and bottom. (ρ2 - ρ1) can be calculated with the temperature difference. I don't know how I should calculate the pressure directly. I can only think of using the ideal gas law, but I'm not sure how that would work in this situation. Any suggestions? Thanks.