1. What weighs more a ton of bricks or a ton of feathers?
Density
What weighs more a ton of bricks or a ton of feathers?

2. What would take up more space. 50 kilograms of feathers…
What would take up more space??? kilograms of feathers….. or a 50 kilograms of steel?? OR

3. What is Density?
Density: the ratio comparing the mass of an object to its volume
It is dependent on the proximity of like atoms or molecules (particles)
An intensive property

4. Mass & Volume
Mass: Measurement of the amount of matter (or stuff) in an object
Measured in grams (g)
Volume: Measurement of the amount of space an object takes up
Measured in milliliters (ml) or cm3

5. Examples of Density @ 20°C
Water 1.0 g/mL
Gold g/mL
Aluminum 2.7 g/mL
Lead g/mL
Hydrogen g/mL
Oxygen g/mL

6. Sinking or Floating?
Materials will float in substances if their density is less than that substance.
Materials will sink in substances if their density is greater than that substance.
Therefore:
Objects with densities greater than 1.0 g/mL will sink in water.
Objects with densities less than 1.0 g/mL will float in water.

7. Lead floats on liquid mercury!

8. Ice vs. Water

9. Finding Density in Lab:
To find Mass: Use scale/balance
To Find Volume:
Liquids: Use graduated cylinder
Solids:
Regular Shapes –determine the volume by formula
Irregular shapes – Use water displacement method

10. Water Displacement Method

11. Calculating Density Density = mass ÷ volume Units:
grams per milliliters = g/mL
grams per cubic centimeters = g/cm3

12. Calculations Using Density
What is the density of a 5.6-mL object with a mass of 12.5 g?
Convert your above answer to lb./ft3.

13. More Calculations:
2. Calculate the mass of a piece of gold with a density of 19.3 g/cm3 and a volume of 12.9-mL.

14. More Calculations:
3. A student places a lb. sample of metal into a graduated cylinder containing mL of water. The water rises to mL. What is the density, in g/mL, of the metal?

15. More Calculations:
4. What is the mass, in grams, of a piece of aluminum with a density of lb./in3 and a volume of 23.9-mL?

16. One more calculation:
5. A 10.3 g piece of aluminum has a density of 2.70 g/mL. What is the volume of the piece of aluminum?