1. 10-25-16 Get ready for bell work
Density 2
Get ready for bell work

2. 1. The image above is a model showing various types of fossils embedded in layers of sedimentary rock.
The law of superposition would predict that layer three is...?
a. ...older than layer 4 and younger than layer 2
b. ...older than layer 1 and younger than layer 5
c. ...younger than layer 2 and older than layer 1

3. This diagram shows layers of rocks that contain fossils
How can you determine that fossil number six and fossil number four are similar in age?
a. These two fossils are the same species.
b. Both of these fossils are sea shells so they must have lived at the same time.
c. These two fossils are in the same layer of sedimentary rock.
d. They do not have a similar age.

4. 3. If deforestation continues unchecked in the Amazon rain forest, certain trees, birds, and other forest dwellers such as jaguars may go extinct.
Which choice below correctly describes the consequence of this decrease in biodiversity?
a. disturbances in weather patterns, leading to a higher average global temperatures
b. a decrease in the number of herbivores due to a lack of natural predators
c. native people will have less food sources, and the food web will be disrupted
d. an increase in the number of producers after a herbivore population boom

5. 4. In the United States, Kudzu vines from Japan were planted next to highways to control erosion starting during the 1930s. These vines grow quickly and rapidly spread out to cover large areas. Kudzu vines smother other plants by blocking sunlight and occupying most of the good soil.
Kudzu vines reduce biodiversity for flora (plants), but they also reduce biodiversity for fauna (animals) and other organisms.
Which choice below correctly describes how Kudzu reduces biodiversity for fauna?.
a. Kudzu vines reduce biodiversity by covering other plants which blocks sunlight and kills them.
b. We have discovered that anti-inflammatory medicine can be made from Kudzu plants.
c. When Kudzu eliminates native plants, then the animals that eat these plants are also effected.
d. Kudzu is beneficial to the soil because it increases the amount of nitrogen in the ground.

6. A student designs an experiment to determine how surface type affects the amount of force needed to roll a ball 20 meters.
What is the independent variable?
a. the type of surfaces used
b. the type of ball chosen
c. the lengths of the surfaces
d. the force needed to roll the ball

7. 6. Dr. Livingston investigated the effect of carbon dioxide on plant height. Over a 6-week period she grew plants in several closed and sealed containers. All the plants received the same amounts of water and light, but the air in each container had a different amount of carbon dioxide.
Which choice is the best example of a control experiment that Dr. Livingston might have done?
a. She could increase the duration of the experiment to 12-weeks.
b. Repeat the experiment over, but do not place any plants in the sealed containers.
c. Dr. Livingston could add more carbon dioxide to each container.
d. Duplicate the experiment, but do not add any carbon dioxide to the containers.

8. 7. Some students measure the mass of a small pile of leaves before and after the leaves decompose. Each time the students measure the mass, they place a container with the decomposing leaves on a balance.
Before recording the mass of the leaves, the students must do which of the following?
a. Add leaves from the other plants to the container
b. Allow the leaves to settle in the container for a few days
c. Subtract the mass of the container
d. Use a metric ruler to measure the volume of the container

9. Think about sinking and floating: Density

10. 1. The image above is a model showing various types of fossils embedded in layers of sedimentary rock.
The law of superposition would predict that layer three is...?
a. ...older than layer 4 and younger than layer 2
b. ...older than layer 1 and younger than layer 5
c. ...younger than layer 2 and older than layer 1

11. This diagram shows layers of rocks that contain fossils
How can you determine that fossil number six and fossil number four are similar in age?
a. These two fossils are the same species.
b. Both of these fossils are sea shells so they must have lived at the same time.
c. These two fossils are in the same layer of sedimentary rock.
d. They do not have a similar age.

12. 3. If deforestation continues unchecked in the Amazon rain forest, certain trees, birds, and other forest dwellers such as jaguars may go extinct.
Which choice below correctly describes the consequence of this decrease in biodiversity?
a. disturbances in weather patterns, leading to a higher average global temperatures
b. a decrease in the number of herbivores due to a lack of natural predators
c. native people will have less food sources, and the food web will be disrupted
d. an increase in the number of producers after a herbivore population boom

13. 4. In the United States, Kudzu vines from Japan were planted next to highways to control erosion starting during the 1930s. These vines grow quickly and rapidly spread out to cover large areas. Kudzu vines smother other plants by blocking sunlight and occupying most of the good soil.
Kudzu vines reduce biodiversity for flora (plants), but they also reduce biodiversity for fauna (animals) and other organisms.
Which choice below correctly describes how Kudzu reduces biodiversity for fauna?.
a. Kudzu vines reduce biodiversity by covering other plants which blocks sunlight and kills them.
b. We have discovered that anti-inflammatory medicine can be made from Kudzu plants.
c. When Kudzu eliminates native plants, then the animals that eat these plants are also effected.
d. Kudzu is beneficial to the soil because it increases the amount of nitrogen in the ground.

14. A student designs an experiment to determine how surface type affects the amount of force needed to roll a ball 20 meters.
What is the independent variable?
a. the type of surfaces used
b. the type of ball chosen
c. the lengths of the surfaces
d. the force needed to roll the ball

15. 6. Dr. Livingston investigated the effect of carbon dioxide on plant height. Over a 6-week period she grew plants in several closed and sealed containers. All the plants received the same amounts of water and light, but the air in each container had a different amount of carbon dioxide.
Which choice is the best example of a control experiment that Dr. Livingston might have done?
a. She could increase the duration of the experiment to 12-weeks.
b. Repeat the experiment over, but do not place any plants in the sealed containers.
c. Dr. Livingston could add more carbon dioxide to each container.
d. Duplicate the experiment, but do not add any carbon dioxide to the containers.

16. 7. Some students measure the mass of a small pile of leaves before and after the leaves decompose. Each time the students measure the mass, they place a container with the decomposing leaves on a balance.
Before recording the mass of the leaves, the students must do which of the following?
a. Add leaves from the other plants to the container
b. Allow the leaves to settle in the container for a few days
c. Subtract the mass of the container
d. Use a metric ruler to measure the volume of the container

17. I Can… Calculate the density of an object given its mass and volume.
TOC #12 Density Problems 2

18. Density Problems # 1 Answers
1. Which square is the densest? Why?
2. Which square is the densest? Why 
I can calculate the density of an object given its mass and volume.

19. Density Problems # 1 Answers
3. What is density? The amount of matter (mass) in a given space (volume)
4. What is the formula for Density? D = m / v
5. What are the units for Density? g/mL or g/cm3
6. Why are these units for density? The units represent the equation that you are working.
I can calculate the density of an object given its mass and volume.

20. Density Problems # 1 Answers
7. Frank has a paper clip. It has a mass of 9g and a volume of 3cm3. What is its density? 9 g ∕ 3 cm3 = 3 g/cm3
8. Frank also has an eraser. It has a mass of 3g, and a volume of 1cm3. What is its density? 3 g ∕ 1 cm3 = 3 g/cm3
9. Jack has a rock. The rock has a mass of 6g and a volume of 3cm3. What is the density of the rock? 6 g ∕ 3 cm3 = 2 g/cm3
I can calculate the density of an object given its mass and volume.

21. Density Problems # 1 Answers
10. Jill has a gel pen. The gel pen has a mass of 8g and a volume of 2cm3. What is the density of the rock?
8 g ∕ 2 cm3 = 4 g/cm3
11. Alicia has a watch. It has a mass of 4g and a volume of 2cm3. What is the density of the watch?
4 g ∕ 2 cm3 = 2 g/cm3
12. Mia has a wallet. It has a mass of 15g and a volume of 5cm3. What is the density of the wallet?
15 g ∕ 5 cm3 = 3 g/cm3
I can calculate the density of an object given its mass and volume.

22. Density Problems # 1 Answers
13. Which layer has the highest density? 4
14. Which layer has the lowest density? 1
15. Imagine that the liquids have the following densities: Which number would go with which layer?
4 10g/cm g/cm3
g/cm g/cm3
I can calculate the density of an object given its mass and volume.

23. Density Problems # 1 Answers
16. Which liquid has the highest density? 3 – syrup
17. Which liquid has the lowest density? 1 – oil
18. Which liquid has the middle density? 2 – water
I can calculate the density of an object given its mass and volume.

24. Density Problems # 1 Answers
Liquid Layers – Check out picture 3:
19. Imagine that the liquids on the right have the following densities: Which number would go with which layer?
g/cm g/cm g/cm3
g/cm g/cm g/cm3
I can calculate the density of an object given its mass and volume.

25. Density Problems # 1 Answers
20. What is the formula for density?
D = m / v
21. What are the units for density?
g/mL or g/cm3
22. What happens if you pour together liquids that have different densities?
They will separate into layers with the least dense on top and most dense on the bottom
I can calculate the density of an object given its mass and volume.

26. Density Problems # 1 Answers
23. Will the liquid on the top have the highest or lowest density?
Lowest
24. Will the liquid on the bottom have the highest or lowest density?
Highest
I can calculate the density of an object given its mass and volume.

27. Density Problems # 1 Answers
25. Jake has a book, a ruler, and a balance. How can Jake find the density of the book with the tools he has? (Hint: Explain HOW you use EACH tool for your answer to be correct!)
Jake would find the volume of the book using the ruler, than he would multiply the L x W x H in cm3.
Jake would find the mass of the book by measuring it on the balance in g.
 Lastly, Jake would find the density by D = m / v in g/cm3.
I can calculate the density of an object given its mass and volume.

28. Density Demonstration: Coke vs. Diet Coke
Compare and Contrast
Discuss with your elbow partner: Coke vs. Diet Coke
Look at the two cans.
What similarities are there? (e.g. same shape)
What differences are there? (e.g. one can is red, one is silver)
What happens when both cans were place in the tank of water.
Why is one can floating?
Looks at the difference between 39 grams of sugar in Coke vs 100 mg of sweetener in Diet Coke
The more “stuff” (matter) is crammed into the same amount of space or VOLUME , that increases the MASS. The relationship of Mass to Volume is Density. The more matter in a defined space, the denser it becomes. The density of water is 1g/cm3. An object will float if the density is less than 1.
I can calculate the density of an object given its mass and volume.

29. Answer the items on the Density Problems #2 Worksheet.
I can calculate the density of an object given its mass and volume.

30. The following liquids were spilled into the tank:
•a green liquid that has a volume of 48 mL and a mass of 36 g
•a blue liquid that has a volume of 144 mL and a mass of g
•a red liquid that has a volume of 96 mL and a mass of g
•a black liquid that has a volume of 120 mL and a mass of 96 g
1. Calculate the density of each liquid. Show your work! Don’t forget the units.
Green liquid: 36 g / 48 mL = .75 g/mL
Blue liquid: g / 144 mL = .90 g/mL
Red liquid: g / 96 mL = 1.2 g/mL
Black liquid: 96 g / 120 mL = .80 g/mL
I can calculate the density of an object given its mass and volume.

31. 2. Determine the order in which the liquids have settled in the tank.
First (bottom): Red Liquid
Second: Blue Liquid
Third: Black Liquid
Fourth (top): Green Liquid
3. What kind of property did you use to distinguish among these four chemicals?
a chemical property C. a liquid property
a physical property D. a natural property
I can calculate the density of an object given its mass and volume.

32. Use colored pencils to color each layer and label the position of the layers in the tank on the diagram shown below.
Green
Black
Blue
Red
Now that you know where the red chemical is inside the tank, how would you remove it?
You would use the drain at the bottom of the barrel to drain the liquid out since it is on the bottom with the greatest density.
I can calculate the density of an object given its mass and volume.