Density

Question 1

What is density?

Answer 1

A measure of how much mass a substance has, per unit of its volume.

Question 2

What is the equation for density?

Answer 2

Density = Mass / Volume

m
———
ρ x v

ρ = rho

Question 3

What is density normally measured in?

Answer 3

Density (kg/m³)
or
Density = (g/cm³)

This is because mass is measured in kg or g, and volume is measured in m³ or cm³.

Question 4

How do you calculate the density of a solid experimentally?

Answer 4

1. Find the mass and the volume of our object

To find the mass, simply place our solid on a ‘balance’ and measure the mass.
The volume depends on whether it is a regular or irregular shape. If it is *(regular(( (like a cube/cuboid), we can find its volume by measuring and then multiplying its length, width and height.
If it is an irregular shape, then you must find its volume using a eureka can that has been filled with water, and an empty measuring cylinder. We place our solid into the eureka can, and a volume of water will flow out of the outlet exactly equal to that of the solid.

2. Lastly, simply plug our values into the density equation.

Density = Mass / Volume

Question 5

How do you calculate the density of a liquid experimentally?

Answer 5

1. Place an empty measuring cylinder onto a balance, and zero the balance to reset it.
2. Pour some of the liquid into the cylinder, and record the mass of that amount of liquid.
3. Divide the mass by the volume, and that gives us our density.

The larger the volume you measure, the more accurate the density will be This is because it minimises the effects of uncertainty in taking your measurements. You could also take multiple measurements and look for anomalies, and then calculate a mean average.