DensityDensity

Intro Chapter Intro Chapter

Density Demo #1

Density Demo #1

• Problems:– What will happen when the small steel ball

is placed in the water?– What will happen when the large steel ball

is placed in the water?

• Hypotheses:– The small steel ball will _________ when

placed in water.– The large steel ball will _________ when

placed in the water.

Density Demo #1

• What will happen when an egg is placed in beaker 1?

• What will happen when an egg is placed in beaker 2?

Density Demo #2

• Observe the eggs when each is placed in beaker 1 and beaker 2.

• What happened? Why?

Density Demo #2

• What do all objects have?– ___________________

• Remember, all objects are made up of something called _________________

– Because objects have mass and are made up of matter they also have_________________.

– All objects take up space

Breaking Down Density

Density Example

1. Students in a Classroom• Think about the number of students in

this room. If you had 10 students (represent molecules) in the room, how would that compare to having 250 students (molecules) in the room?

Which situation would be denser?

• Write a definition for density. Think about the examples provided.– The amount of matter in a given volume.– It’s a ratio.

Density

• Write an equation for Density.– Remember it’s a ratio.

Density

Example Problems

• Directions: Find the missing values for the following density problems.1. Write the correct equation to use.

2. Plug in the numbers.

3. Circle your final answer. (don’t forget units)

• Example Math Problem:– A student determines the mass of a metal

paperclip to be 1.42g (grams).

– The student also determines the volume and finds that it has a volume of 2mL.

• Determine the density of the paperclip.

Density

Example Problems

2. Mass = 150g

Volume = 30cm3

Density = ?

3. Volume = 70 cm3

Density = 30g/ cm3

Mass = ?

Density of Water / Salt Water

1. Using the appropriate tools, determine the density of water / salt water.

2. Create a table to display your results.

3. Using the data you found, approximate the density of the egg.

• Show your work!

Density Mass Volume

Saltwater

Freshwater

Density Data Table

Density of Water / Salt Water

4. If an object is denser than water, what will happen to it when it is placed in water?

5. If an object is less dense than water, what will happen to it when it is placed in water?

Density of Water / Salt Water

6. If you were to carefully pour the water into salt water trying to keep them from mixing. What should happen?

• Do your calculated results make sense with what you observed in the ice lab?

Salt Water Ice Lab & Density

• Do your calculated results make sense with what you observed in the ice lab?

Salt Water Ice Lab & Density

H20 H20 H20

H20 H20

H20 H20 H20

H20 H20 H20

H20 H20

H20 H20 H20

NaCl

NaCl

NaCl NaCl

NaCl NaCl

NaCl

• During the ice lab, Mrs. Gregory obtained a 10mL sample of the salt water from the beaker and massed it on the electronic balance. She determined the mass to be 9.9g. She then took a 10mL sample of melted blue ice water and massed it on the balance. She figured out that the mass was 9.6g. Calculate the density of both substances and determine which is denser, the salt water or blue ice water. Do your calculated results make sense with what you observed in the ice lab?

Example Word Problem