1. DENSITY D = m/v (g/cm3) Mass usually expressed in grams
Volume usually expressed in cm3 or liters, etc.

2. 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

3. The “DMV” Triangle for Volume, Mass, and Density
÷ ÷
D X V
Volume = M D
Mass =
D x V

4. What 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 around OR

5. Density is the measure of the “compactness” of a material
How close the atoms or molecules are to eachother
More than “heaviness” - density includes how much space an object takes up!!
All substances have density including liquids, solids, and gases
Bread slice and compacted bread in large flask of water

6. “Compactness”
Hot air balloon - Describe how a hot air balloon works. Defend your argument.

7. 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

8. 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!!
Straw solute
Denser layers to less dense layers…..

9. What would happen???? Mercury density = 13600kg/m3
Lead density = 11340kg/m3
Sinking vial - make it float

10. Lead floats on liquid mercury!

11. Solids
Ice vs. water…..

12. 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
Beans/ping pong ball; Big jug of water in a pool
Wouldn’t you like to have a bunch of THIS dense material?

13. Factors affecting Density
Temperature
Pressure
Add several drops of red food color to each of two 250-mL Erlenmeyer flasks; fill them with warm tap water. (If tap water is not warm, heat some tap water on a hot plate to °C.)
Add several drops of blue food coloring to each of the other two 250-mL Erlenmeyer flasks; fill them with cool tap water.
Predict the outcome when one flask is inverted over the other.
Place a paper card on top of the vessel filled with warm water. Invert the flask making sure to hold the card in place. Stack it on top of one of the cool water flasks. Remove the card. Remain prepared to catch the flasks.
  ** Visual here.
Place a paper card on top of the flask filled with cool water. Invert the flask making sure to hold the card in place. Stack it on top of the other warm water flask. Remove the card.
Wide mouth containers may also be used.

14. Factors affecting Density
Dissolved solids – in liquids
Concentration and kind of substances

15. Relative Density
The density of a material or substance, relative to another substance
Expressed in a ratio: water = 1g/cc
Water is the substance to which we generally compare other substances
ALSO known as SPECIFIC GRAVITY
Relative Liquid densities: Oil, colored water, and corn syrup in a graduated cylinder.
An H2O ice cube floats in liquid H2O but floats in rubbing alcohol. A can of diet coke floats in water while a can of regular coke sinks (can determine density of sugar versus NutraSweet using balance).

16. DETERMINING DENSITY Use a graduated cylinder
Regular Shapes – mass, then determine the volume by formula
EX: cubes, cylinders, spheres, cones, etc.
Irregular shapes – mass, then measure displacement of a liquid (usually water) by that irregularly shaped object
Use a graduated cylinder
Add water to a predetermined level - record.
Gently drop in the irregularly shaped object.
Read the graduated cylinder – record.
Subtract the first water level from the second – this is the volume

17. Density Table SINK or FLOAT In Water (D = 1.0 g/mL) Float Float Float
(alcohol)
Float
(fuel)