30 ms·

I would think it's about the "apparent weight" i.e. including the buoyancy in air. So it's density would be 1.2+0.9= 2.1mg/cm^3. Also they count the whole cm^3

• ars 15y ago
  No, the apparent weight would be 0.9 - the air inside the material is "floating" in ambient air, and would not be measured on an ordinary scale. Technically you also have to account for the slight buoyancy the metal has in air (but it's far below the error margin so it's ignored). Basically on earth when you weigh things you are measuring weight, even if you say grams (which are supposed to be mass). If you want true mass you have three choices: 1. Weigh in vacuum. 2. Use a scale that shakes the material on a spring and measure the frequency (i.e. measure inertia). 3. Calculate the volume of the material, calculate the weight of air of that volume and add that weight to your measured weight. No one ever does this since it doesn't matter. But if you want to be exact....