1. The problem statement, all variables and given/known data What is the longest vertical straw you could possibly drink from? 2. Relevant equations 3. The attempt at a solution The solution says to use p = ρgd, but I don't understand why or how you can use it. I have a suspicion p = 101 325 Pa (atmospheric pressure) and ρ = 1000 kg/m^3, the density of water And it actually gives the right answer, which is 10.3 m. I just don't understand why this works or even why you use that formula. Thanks!