Measurements eight not always be the same due to different factors, so by taking the average scientist takes in account all of the measurements and finds one value that satisfies them all. The volumes of the two metals that were given were very similar, ml and ml for Copper and Aluminous respectively. Their masses in the other had are very different, the copper had a mass of 160. G and aluminous 47. G. Since their volumes are similar but their masses are different this must mean that their densities differ. As shown above this is true, Copper that has a higher mass has a higher density of 8. , and Aluminum with the less mass has a density of 2. 7. If the experimenters had another piece of the same material but a mass twice as big then the density would remain the same. Mass and volume are directly related so when one goes up the other increases as well, and since the formula is d=m/v if they both change the result will remain the same. When an object is heated it expands outwards therefore occupying more space. This means that the density will decrease because the mass will remain the same. So taking account the formula above if only Volume is increased and mass remains instant then the result which is density will decrease.
That is why hot air will rise when heated. Hot air has less density than cold air so the more dens air will fall down and the less dens will rise up and take its place. Ice floats because it is about 9% less dense than liquid water. In other words, ice takes up about 9% more space than water, so a liter of ice weighs less than a liter of water. The heavier water displaces the lighter ice, so ice floats to the top. The same things happen in balloons and airships that use helium gas, the gas has less weight than and less density than the air so it floats and goes up.