2DensityIt is a measure of compactness of how much mass is tightly squeezed into a given volume.Is the ratio of mass and volume in an object.D= M/Vg/ml or g/cm3
3DENSITY D = m/v (g/cm3) (g/ml) Mass usually expressed in grams Volume usually expressed in cm3 or milliliters, etc.
4Density Density = amount of matter per unit volume Density is the ratio of mass to volumeIf the volume stays the same and the mass increases the density will increaseIf the mass stays the same and the volume increases The density will decrease
5The “DMV” Triangle for Volume, Mass, and Density ÷ ÷D X VVolume =MDMass =D x V
6Density is the measure of the “compactness” of a material How close the atoms or molecules are to each otherMore than “heaviness” - density includes how much space an object takes up!!All substances have density including liquids, solids, and gasesBread slice and compacted bread in large flask of water
7What would take up more space. A kilogram of feathers… What would take up more space??? A kilogram of feathers….. or a kilogram of steel??ROCKS - pass aroundOR
8“Compactness”Hot air balloon - Describe how a hot air balloon works. Defend your argument.
9Density The density of water is 1.0 g/ml Objects with densities greater than 1.0 g/ml will sink in water
10Objects with densities less than 1.0 g/ml will float on water DensityObjects with densities less than 1.0 g/ml will float on water
11Ice floats therefore it is less dense than water Ice mostly remains underwater with only a portion of it being exposed
13Gases How much kinetic energy do the molecules have?? The greater the kinetic energy……the greater the volume…… and the less dense that gas is!!Therefore, cold air is more dense than warm air
14Low pressure weather system means warmer air tends to rise, High pressure systems indicate a colder more dense air mass that will……. SINK!!!
15LIQUIDSThe more dissolved solids in a solution, the more dense (such as ocean water)Cold water in lakes tend to sink (this creates a constant mixing of water, nutrients, and other substances)Kinetic energy again!!Straw soluteDenser layers to less dense layers…..
16What would happen???? Mercury density = 13600kg/m3 Lead density = 11340kg/m3Sinking vial - make it float
19SOLIDSIce is less dense than water (which is why lakes and ponds have a thin layer of ice covering in winter, with water underneath)Various rocks, woods, metals have a characteristic density specific to that substanceBeans/ping pong ball; Big jug of water in a poolWouldn’t you like to have a bunch of THIS dense material?
20Archimedes and the Kings Crown 250 b.c., the Greek mathematician Archimedes - story
21CalculationsIf 96.5 grams of gold has a volume of 5 cubic centimeters, what is the density of gold?
22CalculationIf 96.5 g of aluminum has a volume of 35 cm3, what is the density of aluminum?
23CalculationIf the density of a diamond is 3.5 g/cm3, what would be the mass of a diamond whose volume is 0.5 cm3?
24What is specific gravity? A comparison of the density of a substance and the density of water is specific gravity
25Density Table SINK or FLOAT In Water (D = 1.0 g/mL) Float Float Float (alcohol)Float(fuel)