1. Density
12 November 2018 Objectives: To compare materials in terms of density. To calculate density from experimental measurements. Homework Revise for test on Monday

2. Starter (5 mins)
Place a range of objects on the front bench and ask the students to decide the order of weight. The students are not allowed to touch them.

3. Discuss the findings of the Starter to establish students’ understanding of mass and density supported by section P4.1 of the Student’s Book.
Show them two identically sized objects with different densities and ask why they have different masses/weight
Answers should include keyword: particles

4. What can you tell me about these four diagrams?

5. Density takes into consideration mass and volume
If an object has the same volume, but weighs more, it has a different density

6. Practical
Students now measure the densities of some regular and irregular objects

7. Mass Volume Mass Volume Working out the Density of different materials
To work out the density of any particular material, you need two different pieces of information. These are:
Mass
How much stuff there is in the material (measured in g)
Volume
How much space the material takes up (measured in cm3)
To work out the density of a material, you do the following calculation:
Mass
Volume

8. Mass Volume Density = Working out the Density of different materials
Measured in g
Measured in cm3
Measured in g/cm3
Measured using scales
Measured using a ruler
Find out the width, the length and the height
Multiply these together

9. Length x Width x Height = Volume
Working out the Density of different materials
Length x Width x Height = Volume
1cm x 1cm x 1cm = 1cm3
1cm x 5cm x 1cm = 5cm3
1cm x 4cm x 2cm = 8cm3
2cm x 3cm x 2cm = 12cm3

10. Length x Width x Height = Volume
Working out the Density of different materials
Length x Width x Height = Volume
7cm
10cm
5cm
10cm x 5cm x 7cm = 350cm3

11. Copy the equation into your book
Mass
Density =
Volume

12. How do we work out density?
Material
Mass (g)
Volume (cm3)
Density (g/cm3)
Brick
2000
1020
Gold bar
193 10
Wood 14 20
Ice Cube 7 8

13. The volume of a cuboid
Volume of a cuboid = a × b × c =abc where a, b and c are the lengths of the sides of the cuboid.

14. Demonstrate
Material
Mass (g)
Volume (cm3)
Density (g/cm3)

15. Working out Density
You will be given a set of different materials. For each one, you will need to work out the density. Record your results in a table like the one below:
Material
Mass (g)
Volume (cm3)
Density (g/cm3)
Stone
Iron
Aluminium
Wood
Polystyrene
Use these results to rank the materials in order of most dense to least dense.

16. I want to find out the density of this rock…..

17. Working out the volume of an irregular object
Stage 1
Stage 2
Stage 3

18. Density of Water is 1g/cm3
Floating or Sinking?
Density of Bone is 1.8g/cm3
Density of Cork is 0.24g/cm3
Density of Cork is 3.01g/cm3
Density of Ice is 0.90g/cm3
Density of wood is 0.77g/cm3
Density of Water is 1g/cm3

19. Plenary (5 mins)
Show two similarly sized objects made (ostensibly) of the same material, but one hollow and the other solid.
Explain how the objects look the same, have the same volume, and appear to be made of a similar material, yet have very different masses.