Chapter 2.6

What is density?

DensityDensity is a measure of how tightly

matter is packed into a given volume

Which box has more density?

1st box has more density

Which box has more density?

RED BOX

Formula for Density

To calculate density, we use the formulaDensity = mass

volume

EXAMPLESuppose you know the mass of an object is 30 g and the volume is 15 cm3.Density = mass/volumeDensity = 30g/15 cm3

Density = 2g/cm3

Density ContinuedDensity is a property that can be used to identify an

object.For example…

• gold = 19.3 g/cm3

• mercury = 13.6 g/cm3

• lead = 11.3 g/cm3

• silver = 10.5 g/cm3

• aluminum = 2.7 g/cm3

• rubber = 1.1 g/cm3

• water = 1.0 g/cm3

• cork = 0.24 g/cm3

• air = 0.0013 g/cm3

Sink or Float???• Matter that has a greater density

that water will sink in water. • Matter with a density lower than of

water will float.

Coke vs. diet coke experiment• Which coke will float and which will

sink??? Tell me your prediction.

Did you know???Most people can float because their density is slightly less than that of water.

Self Check- page 441. What is density?2. Which would have more matter – a 1-cm cube of

lead or a 1-cm cube of rubber?3. Suppose you have a metal bar. It’s mass is 57.9

g and it’s volume is 3 cm3. What is it’s density?4. If you cut the metal bar from question 3 in half,

what would the density of each half be?5. What is the metal whose density you calculated

in question 3?6. If you put a piece of cork in a container of water,

would it sink or float? Why? Hint - Use the table on the recent slide to help answer the question.