In what ways can we measure density?

Topic 1: Density

What is density?

Density is the amount of matter in a given amount of space.

Density can be compared in solids, liquids and gases.

What is the formula for density?

Density = Mass Volume

Formula can be arranged to solve for any variable.

Volume = Mass or Mass = Density x Volume Density

Density Units: for a regular object is g/cm3

for a irregular object is g/ml

Example: A radio has a mass of 120.0 g and a volume of 12.0 cm3. Determine its density.

What instruments are needed to measure the mass and volume?

~ triple beam balance and a ruler

Density = Mass Volume

= 120.0 g = 10.0g/cm3

12.0cm3

Does a change in size or shape affect density?

No, if you change the size or shape of the same material, the density remains the same

What happens to density if the temperature of an

object changes?

As temperature increases, density decreases. This is an inverse relationship = meaning when one variable goes up, the other goes down.

What happens to density if the pressure on a object changes?

As pressure increases, density increases. This is a direct relationship = when one variable goes up, so does the other.

What is the density of liquid water?

The density of water is 1.0 g/ml.

How do you determine the relative density of an object?

In order to determine relative density, put the objects (solid, liquid or gases) in order from most dense to least dense.

In the example below, the liquid is water. Determine the order of blocks A-E of most dense to least dense.

A, C, E, B, D

How do phases of matter affect density?

Solids have the highest density because their molecules are tightly packed together.

Gases have the lowest density because their molecules are loosely packed together.

Liquids are in between solids and gases: they have “medium density and medium packing”

What phase of matter is water the most dense?

The phase of matter in which water is most dense is liquid @ 4°C