1. The problem statement, all variables and given/known data Glycerin is poured into an open U-shaped tube until the height in both sides is 36 cm. Ethyl alcohol is then poured into one arm until the height of the alcohol column is 30 cm. The two liquids do not mix. What is the difference in height between the top surface of the glycerin and the top surface of the alcohol? 2. Relevant equations 3. The attempt at a solution Well I know that the pressure at both sides has to equal 0....and I know that P(d)=Ptop+pgd, but where does P come from?