 OK, so let's try one of these volume displacement density problems. It says, a piece of metal ore weighs 8.25 grams. When a student places it into a graduated cylinder containing water, the liquid level rises from 21.25 mils to 26.47 mils. What is the density of the ore? So let's write down what the problem gives us. Mass equals 8.25 grams. It also told us that the initial volume was 21.25 mils. The final volume it gave us was 26.47 mils. So in order to find the volume difference, so the change in volume, that equals the volume of the object or the ore. That's the mass of the ore, so the volume of that object. So the change in volume, that's going to be the final volume minus the initial volume. Does that make sense? That's a change in volume. So what is that going to be? 26.47 mils minus 21.25 mils. 22 mils. So that's the volume of the object. That's the mass of the object. So density equals mass divided by volume. So the mass of the object is 8.25 grams divided by the volume of the object. 5.22, 8.25 divided by half. So how many is 8.53? So 1.58, and units, grams per mil. So that's the density of the ore. Questions?