density [Applause] just like all matter water has physical properties that can be measured and calculated to find the mass of water you need a beaker and a scale first find the mass of the empty beaker then fill the beaker up with your desired amount of water next use the scale to find the mass of the filled beaker to find the mass of just the water we need to subtract the mass of the empty Beaker from the full beaker our sample is 100 grams the volume of water can be measured using a graduated cylinder our sample is 100 milliliters density is calculated by dividing the mass by the volume plug in your measured Mass we measured ours to be 100 grams divide that by the measured volume R volume was 100 milliliters water's density is one gram per milliliter objects with a density greater than one will sink when placed in water objects with a density of less than one will float when placed in water if a block has a density of 0.1 it will float because its density is less than one another black with a density of 0.5 will also flow because its density is less than one notice that more of the block was below the water line another block with a density of 0.9 is also less dense than water so it will float we can see that as density increases more of the block is below the water line scientists have discovered that the Block's density tell us exactly where the block will come to rest if the density is 0.1 then 10 percent will be below the water line to calculate where a block will come to rest just convert density to a percent density also explains why ice floats if you freeze water it expands let's use the black dots to represent the atoms in water when you freeze water no new atoms are added to the water so because of the expansion there is more room between the atoms compared to the atoms in liquid water the atoms in the ice are not as tightly packed together causing the ice to float so try calculating density for yourself its mass divided by volume