A tonne of lead and a tonne of feathers have the same mass because a tonne is defined as 1000 kg. While feathers take up more space than lead, the mass of each is the same since they are equal volumes. Density is calculated by dividing the mass of an object by its volume and compares how compact or spread out the mass is. Higher densities mean more mass is packed into a smaller volume. Common materials like wood, water and iron are provided as examples to compare densities based on a 1 cm3 sample of each.

1. Which is heavier,a tonne of lead or a tonne of feathers?
Tonne = 1000 kg
A tonne of feather is just as heavy
as a tonne of lead

2. •We know that feathers are lighter than lead.
•One tonne of feathers occupies much more space
than one tonne of lead

3. Which has more mass, 1 kg of water or 1 kg
of air?

4. • If you took two identical boxes and
filled one with lead and one with
feathers.
• Which box will be heavier?
• The box full of lead would be much
heavier than the box of feathers

6. Wood Water Iron
1 cm3 1 cm3 1 cm3
0.50 g 1.00 g 8.00 g
• In science, we don’t say lead is heavier than feathers.
• We say that lead has greater density than feathers.
How do we measure density?
Density is the Mass per unit Volume

7. Density = Mass
Volume
g or kg
cm3 or m3
g/cm3 or kg/m3

9. Watch video

10. Measuring mass of solid

11. Measuring mass of liquid

12. Measuring mass of liquid

13. Measuring volume of solid
1- Regular shape

14. Measuring volume of solid
1- Regular shape

15. Measuring volume of solid
1- Regular shape

16. Measuring volume of liquid

17. Measuring volume of liquid

19. Measuring volume of irregular solid

20. Measuring volume of irregular solid

21. Measuring volume of irregular solid

23. Solve the question
Step 1: An empty measuring cylinder was placed on an electronic balance.
The reading on the balance was recorded (54.0g)
Step 2: Salty water was poured into the measuring cylinder. The new reading
on the balance was recorded (115.2g)
Step 3: The volume of the salty water was read from the measuring cylinder
(60cm³)
a) Calculate the mass of salty water
b) Calculate the density of the salty water

25. Solve the question
A rectangular block of steel measures 4cm x 2cm x 1.5cm
Its mass is 93.6g
a) Calculate the density of steel

26. Solve the question
A fish tank measures 80cm x 20cm x 25 cm. it is to be filled
with water, density 1.0g/cm³.
a) Calculate the mass of water in the tank when it is full.