Density

Density = mass / volume (D = m/v)

Mass = amount of stuff (matter)

-- NOT weight, which is mass times gravity

You weigh less on the moon, but your mass is the same.

Density

Volume = amount of space a thing occupies. L x W x H (cm3) or graduated cylinder (ml).

** Density measures how much stuff (mass) fits in a certain amount of space (volume).

Examples

Suitcase analogy

Styrofoam cup

Styrofoam bag vs. paper clip = more mass doesn’t mean more dense.

Density

The more closely packed stuff is, the denser it is.

Water has a density of 1 g/cm3

Is a broken piece of rock the same density as the original rock?

YES.

Density

Temperature = how fast atoms are moving.

Heat excites atoms and they bump into each other... temperature increases.

Excited atoms move apart, so density decreases (less dense).

Temp. vs. Density

Density

Pressure:

Pressure causes volume to decrease.

Atoms get pushed together and packed tightly.

As a result, density increases

Pressure vs. Density

Density

When Earth was formed:

- dense material sank (mantle/core. - lighter material floated (crust)

Density differences = convection.- weather- ocean currents