1. TOPIC: Lab Skills AIM: How do we determine density?
DO NOW: Explain how layers exist in cappuccino.
Layers exist in cappuccino because ________________________________________________________________________________

2. Density
The measure of the amount of mass that is in each unit of volume
mass per unit volume

3. Instruments needed To measure density
Triple beam balance for mass
Graduated cylinder for volume of a liquid
Metric ruler for volume of a solid

4. Units used for density or
Grams/ml or
Grams/cm3

5. Box A has a greater density than Box B
Because Box A has a greater mass (more matter/ molecules) in the same volume

7. Warm air rises b/c it is less dense than cold air which sinks.

8. Density of water
1 gm/mL

9. Why will an object
float or sink?
FLOATS when the density of the object is LESS than the density of the liquid.

10. SINKS when the density of the object is GREATER than the density of the liquid.
Less dense than water
More dense than water

11. Which is more dense?
Salt water

14. Warm water rises b/c it is less dense than cold water which sinks.

15. Each pure substance has it’s “own density” no matter what size it is.
Facts
Each pure substance has it’s “own density” no matter what size it is.

16. Cut the substance in half each half would still have the same density
So……If I
Cut the substance in half each half would still have the same density
cut it in half

17. Cut the block in half M = 20 gm V = 10 mL M = 10 gm V = 5 mL
Density = 20/10 = 2 gm/mL
Cut the block in half
M = 10 gm V = 5 mL
Density = 10/5 = 2gm/mL

19. wood
plastic
rubber
copper

20. How is denisty calculated?
AIM:
Mass
How is denisty calculated?
Density =
Volume M D V

21. M D V Denisty = Mass / Volume Mass = Density X Volume

22. Example #1:
1. What is the density of a metal block that has a mass of 525 gm and a volume of 50 cm3?

23. D = m v
D = 525 gm
50 cm3
D = 10.5 gm/cm3

24. What is the block made of?
Silver =
10. 5 g/cm3

25. Example #2
The mass of a marble is 8.8 gm. It has a volume of 2 mL. What is it’s density?

26. D = m v
D = 8.8 gm
2 mL
D = 4.4 gm/mL

28. Example #1
M = 45gm
D = 20.1 gm/mL
Volume = ? M D V

29. V = M D
V = 45 gm
20.1 gm/mL
V = 2.2 mL

30. It’s density is greater than the density of water (1 gm/mL)
Will this
object
float or
sink in
water?
Why?
Sink
It’s density is greater than the density of water (1 gm/mL)

31. Example #2
D = gm/mL
V = 1.6 mL
Mass = ? M D V

32. M = D x V
M = 3.5 gm/mL x 1.6mL
M = 5.6 gm