# Required Practical 17: Density

## About this practical...

This practical has good links with mathematics so make sure that you link this in your mind. By now, you should understand density and how to calculate it, however, we very rarely get to, or need to measure it ourselves. By the end of this, you should know how to, and more importantly, understand how to measure the density of a regular shape (e.g. a metal cube), an irregular shape (e.g. a chess piece) and a liquid (e.g. cooking oil).

## Method:

Method 1: Density of a regular object

1. Using a balance, find the mass (kg) of a solid block of regular shape (steel cube)

2. Measure the width, height and length then calculate the volume (m^{3})

3. Calculate the density by dividing the mass (kg) by the volume (m^{3}).

Method 2: Density of an irregular object

1. As above, find the mass of the object using a balance and record it (kg)

2. Setup a Eureka can over the edge of a sink and fill with water over the level of the spout

3. Allow the water to drain

4. Place a measuring cylinder underneath the spout

5. Gently lower the irregular object into the Eureka can. Do not put your fingers

6. The volume of water displaced is the volume of the irregular object. Read this value off the measuring cylinder

7. Calculate the density as above. Ensure that you convert to the correct units: mass (kg) & volume (m^{3}).

Repeat for a variety of objects and materials.

## Safety & Managing Risks

Usual lab rules must be followed: Bags and stools tucked away and notify the teacher of any spills or breakages immediately. For more detailed information, please consult CLEAPSS.

## Technician notes:

Eureka/displacement cans

Measuring cylinders (100 ml and 25 ml)

Selection of cubes of different materials

Selection of irregular objects on cotton/strings

Top pan balances

Beakers (100ml)

This page was updated on: 8th January 2022