2. oneone CS-6B Objective: To determine if substances will sink or float in order to conclude about their relative densities. CSI Note: Why do substances sink or float? HAVE YOU FOLLOWED THE STEPS FOR STARTING CLASS?? Drill: 1. Get a Lesson Sheet from the SET. 2. Complete the Drill portion only.

3. oneone CS-6B Let’s Review

4. oneone CS-6B To find the density: Divide the mass by the volume. Density = Mass ÷ Volume

5. oneone CS-6B Units for Density: g/mL or g/cm 3

6. oneone CS-6B **The density of a substance at a given temperature is the same for all samples of that substance, thus making density a characteristic property.

7. oneone CS-6B HOMEWORK CHECK

8. oneone CS-6B Calculate the density: Show 3 lines of work. (2 decimal places) Substance 1: Mass = 85 gVolume = 10 cm 3 Density = Mass ÷ Volume Density = 85 g ÷ 10 cm 3 Density = 8.5 g/cm 3

9. oneone CS-6B Calculate the density: Show 3 lines of work. (2 decimal places) Substance 2: Mass = 150 gVolume = 2.5 cm 3 Density = Mass ÷ Volume Density = 150 g ÷ 2.5 cm 3 Density = 60 g/cm 3

10. oneone CS-6B Calculate the density: Show 3 lines of work. (2 decimal places) Substance 3: Mass = 33.92 g Volume = 3.2 cm 3 Density = Mass ÷ Volume Density = 33.92 g ÷ 3.2 cm 3 Density = 10.6 g/cm 3

11. oneone CS-6B If you had 200g of Substance 1, what would the density of the substance be? 8.5 g/cm 3

12. oneone CS-6A If you had 5.0 cm 3 of Substance 2, what would the density of the substance be? 60 g/cm 3

13. oneone CS-6B If you had any amount of Substance 1, what would the density of the substance be? 8.5 g/cm 3

14. oneone CS-6B WHY???? Density is a characteristic property!!! It does not change for a given substance!!!

15. oneone CS-6B Review Activity a.Look at your tag. b.Compute the density of your substance. c.Based on the density, locate all of the students that could possibly have the same substance.

16. oneone CS-6B Think about these questions. What will grains of sand do when dropped in water? How much might a cruise ship weigh? Do you need to make any corrections to your drill answer?

17. oneone CS-6B Why do substances sink or float? It’s not based on the weight. It’s based on the density.

18. oneone CS-6B Substances that are more dense than the substance they are in tend to sink. Substances that are less dense than the substance they are in tend to float.

19. oneone CS-6B THE DENSITY OF WATER IS 1 g/cm 3. What does this mean?

20. oneone CS-6B Use your knowledge of sinking and floating and the density of water to complete the chart in your lab.

21. oneone CS-6B You may not always know the exact densities of substances, but you can tell the relative densities of substances (whether one substance is more or less dense than another) based on sinking and floating. This concept is used when creating a density tube.

22. oneone CS-6B 1. Look at the information below. Substance 1 Density = 7.03 g/cm 3 Substance 2 Density = 7.2 g/cm 3 Substance 3 Density = 7.15 g/cm 3 Substance 4 Density = 0.75 g/cm 3 2. Order the substances by their densities from least to greatest. 3. Diagram how the substances will layer.

23. oneone CS-6B Density Tube http://www.youtube.com/watch?v=-CDkJuo_LYs Extra Credit

24. oneone CS-6B Homework: In you Log Book, write about 3 things you learned today.