1. Density

2. Density Which would have more mass?
How much matter is inside each object?

3. Density Which has more volume?
How much space does each object take up?

4. Density Which has more density?
Density depends on BOTH the size of the object AND the material contained inside.

5. Density Matter is made of atoms which are particles that have mass.
Density depends on mass AND the number of particles packed into a given volume.
Density: the amount of mass per unit volume of a material.

6. Density
Most dense
Least dense
Think of density as a measurement of how close together the particles of a substance are.

7. Density
The volume of air has fewer particles, thus less mass than the same volume of water.
Thus, the density of air is less than the density of water.
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8. Density
D = m V
D – density, the unit is g / cm3 (solids) or g / mL (liquids)
m – mass, the unit is g
V – volume, the unit is cm3 (solids) or mL (liquids)

9. Density
Example: Calculate the volume of a rock that has a mass of 12 g and a density of 3 g/cm3.
V= m D
V= 12 g
3 g/cm3
V= 4 cm3

10. Density
Density depends on the material an object is made from, NOT its size.
An entire chocolate bar will have the same density as just one piece. It’s all made from the same material – chocolate.

11. Density
Density depends on the mass of the particles. (more mass = more density)
Density depends on the distance between particles. (more distance = less density)
Gases are usually less dense than solids or liquids because particles are far apart.

12. Density

13. Density

14. Density

15. Measuring Density Measure its mass. Measure its volume.
Divide its mass by its volume.

16. Measuring Mass For a solid, place it directly on a balance.
For a liquid:
Measure the empty container.
Measure the container AND liquid.
Subtract the container from the total mass.

17. Measuring Volume
For a liquid, use a graduated cylinder.

18. Measuring Volume For a regular solid (all sides are rectangles):
Measure its length, width, height.
Multiply all 3 numbers together.

19. Measuring Volume
For an irregular solid, you have to use the “displacement” method:
Record the volume of water in a graduated cylinder.
Place the object CAREFULLY (without splashing) into the graduated cylinder, and record the new volume.
Subtract the volume of the water from the combined volume. Then you know the volume of just the object.

20. Density is a Physical Property
A physical property is something you can measure without changing the composition of the material.
When you measure an object’s mass and volume, you don’t change it into something else.

21. Density is a Physical Property
Scientists can use density to help them identify substances such as minerals, compounds, etc.
For example pure gold can be distinguished from fool’s gold (pyrite) by comparing their densities.
Gold
19.32 g/cm3
Fool’s Gold
(Pyrite)
5.01 g/cm3

22. Density equals ____ divided by volume. A force B matter C solid D mass

23. Density ____ as the distance between particles in an object ____.
A increases; decreases
B increases; increases
C decreases; decreases
D none of the above

24. 3.1 Density
Calculate the volume of a rock that has a mass of 12 g and a density of 3 g/cm3.
A 9 cm3
B 15 cm3
C 4 cm3
D 4 cm

25. Gold has a density of 19. 3 g/cm3. What is the volume of 19
Gold has a density of 19.3 g/cm3. What is the volume of 19.3 g of gold?
A 19.3 cm3
B 5 g/cm3
C 15 g/cm3
D 1 cm3

26. Density is mass per unit ____. A force B matter C pressure D volume
SCI 8.a
Density is mass per unit ____.
A force
B matter
C pressure
D volume

27. SCI 8.b
A 15g object is placed in a graduated cylinder of water. The water level is at 24 ml. When the object is removed, the water level is at 19 ml. What is the density of the object?
A 5 g/cm3
B 4 g/cm3
C 3 g/cm3
D 19 g/cm3

28. 3-1 Vocab – Density Text p.130-137
atom
mass (text p.11)
volume (text p.10)
graduated cylinder (text p.10)
triple-beam balance (text p.11)
rectangular solid
displacement (text p.136)