Density is how much matter(mass) is packed into a given amount of space (volume)
Density is the relationship between an objects mass and volume expressed as a ratio.
Density= Mass or D= M
The ratio will always remain the same for an object even though it may be a different size. As the objects volume increases so does its mass.
For example- 2 pieces of gold
Sample a 38.6g Sample b 77.2g
2.0cm 4.0cm
The density for both samples is 19.3g/cm
No matter what size piece of gold you have it will always have the same density as another piece of gold if it is under the same conditions of temperature and pressure.
As the temperature of an object increases the motion of its particles increases. The particles spread out more, increasing volume. As temperature decreases, the object’s particles contract decreasing volume.
If the volume of an object goes up, its density will go down.
Ex.- 200g density = 5.0g/cm 200g density= 2.5g/cm
40cm 80cm
As temperature increases, Density decreases.
As temperature decreases, Density increases.
As the pressure exerted on an object increases, The particles in the object will be pushed closer together making its volume decrease. A decrease in volume causes the density to go up.
If pressure is removed particles are able to spread out, which will decrease the volume, decreasing the density.
Ex.-50g density = 2g/cm 50g density = 5g/cm
25cm 10cm
As pressure increases, Density increases.
As pressure decreases, Density decreases.
Water does not react the same way to temperature changes as other types of matter do.
Water does not have its highest density in the solid state.
Ice floats so it can’t be denser than liquid water.
As water freezes its particles expand, increasing volume, decreasing density.
Water has its highest density in the liquid state at a temperature of 4 C. Any temperature above or below has a lower
density.
Water’s highest density is 1.0 g/cm at 4 c.
Any object with a density less than water will float on or near the surface of the water.
Any object with a density = to water will float in the middle of the water.
Any object with a density greater than water, will sink to the bottom.
The density of water can be represented graphically.
Another object’s density may be compared to water in graph form.