Presentation on theme: "DENSITY It 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/V."— Presentation transcript:
It 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/V g/ml or g/cm3 2
D = m/v (g/cm 3 ) (g/ml) Mass usually expressed in grams Volume usually expressed in cm 3 or milliliters, etc.
Density = amount of matter per unit volume Density is the ratio of mass to volume If the volume stays the same and the mass increases... the density will increase If the mass stays the same and the volume increases... The density will decrease
The DMV Triangle for Volume, Mass, and Density M ÷ ÷ D X V Density = MVMV Volume = MDMD Mass = D x VD x V
How close the atoms or molecules are to each other More than heaviness - density includes how much space an object takes up!! All substances have density including liquids, solids, and gases Density is the measure of the compactness of a material
What would take up more space??? A kilogram of feathers….. or a kilogram of steel?? OR
9 The density of water is 1.0 g/ml Objects with densities greater than 1.0 g/ml will sink in water
10 Objects with densities less than 1.0 g/ml will float on water
11 Ice floats therefore it is less dense than water Ice mostly remains underwater with only a portion of it being exposed
Solids Ice vs. water…..
Gases 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
Low pressure weather system means warmer air tends to rise, High pressure systems indicate a colder more dense air mass that will……. SINK!!!
LIQUIDS The 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!! Denser layers to less dense layers…..
What would happen???? Mercury density = 13600kg/m 3 Lead density = 11340kg/m 3
Lead floats on liquid mercury!
Solids Ice vs. water…..
SOLIDS Ice 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 substance Wouldnt you like to have a bunch of THIS dense material?
Archimedes and the Kings Crown daily/images/2007/07/18/archimede s.jpg
21 If 96.5 grams of gold has a volume of 5 cubic centimeters, what is the density of gold?
22 If 96.5 g of aluminum has a volume of 35 cm 3, what is the density of aluminum?
23 If the density of a diamond is 3.5 g/cm 3, what would be the mass of a diamond whose volume is 0.5 cm 3 ?
24 A comparison of the density of a substance and the density of water is specific gravity
SINK or FLOAT In Water (D = 1.0 g/mL) Float Sink Float (alcohol) (fuel)