## Density Destiny

### Julie SearLeon County Schools

#### Description

Which is more dense, a block of wood or a glass marble? Students will answer this question as they measure and investigate the densities of several objects.

#### Objectives

The student knows ways in which substances differ (for example, mass, volume, shape, density, texture, reaction to heat and light).

#### Materials

Materials for class demonstration:

-One can of regular soda
-One can of diet soda
-Transparent container large enough to allow both cans to float/sink
-Water (enough to fill the container ľ way)
-Dry erase board eraser
-Rock
-Triple beam balance
-Ruler
-Calculator
-Dry erase board

Materials for student investigations – (per groups of 2 students):

-Triple beam balance
-12-inch ruler
-Calculator
-Data Analysis Worksheet, one per student (see associated file)
-Glass marble
-2 blocks of wood – different sizes
-“C” battery
-3 X 3 block of Styrofoam
-Paper towels (for clean-up)

#### Preparations

1. Purchase any materials that you do not have available in your supplies, eg.,
-One can of regular soda
-One can of diet soda
-Transparent container large enough to allow both cans to float/sink
-Dry erase board eraser
-Ruler
-Glass marbles - one per group
-2 blocks of wood per class – different sizes
-“C” batteries - one per group
-3 X 3 block of Styrofoam - one per group
-Paper towels (for clean-up)cannot find those listed.
Note - You can purchase glass marbles and Styrofoam at a craft store.
2. Prepare copies of the 'Data Analysis Worksheet', one copy per student. If you do not have access to materials listed in this lesson, you can download the 'Data Analysis Worksheet' and change the information before you make copies.
3. Ask your shop-teacher to cut the blocks of wood for you.
4. Set-up the large container of water and 2 cans of soda for the demonstration.
5. Divide the student lab materials into sets for each team of 2 students.
6. Pre-assign lab groups of 2.

#### Procedures

Note for teacher: Before implementing this lab in your classroom, students must have prior understanding and experience in measuring both the mass and volume of a variety of objects. Prior investigations for mass should include using a triple beam balance. Prior investigations for volume should include measuring a “regular object” (for example, a brick, book, cube, block) applying the equation “length x width x height”. Students should also have practice measuring the volume of an irregular solid, eg., a rock or marble, using the water displacement method.

Attention Getter:

1. Have a large container of water set-up in front of the class for demonstration. Show the students that you have one can of diet soda and one can of regular soda. Ask them what they think will happen when you place both cans into the container of water.

2. After some class discussion, place both cans in the water. Ask the students to describe what is happening and why.

Background Review:

1. Pass out the Data Analysis worksheets to students (students are to complete the Background Review section of the Data Analysis Worksheet as the teacher introduces concepts and practice problems).

2. Introduce the concept of density (students are to write the definition of density as presented by the teacher).

3. Introduce the formula for calculating density, using mass and volume.
Density = Mass (g) / Volume (mL)

4. Review procedures for determining an object’s mass and volume (for regular and irregular objects).

5. Demonstrate this process by (students are to perform calculations along with the teacher):

a. Calculating the densities of the two cans of soda used in the demonstration. **In this case, the volume amount is written on the can!
b. Calculating the density of a rock (small enough to fit in your 100 mL graduated cylinder).
c. Calculating the density of a dry erase board eraser.

Student Investigation:

1. Instruct the students, working in teams of 2 (previously assigned), to collect all materials from a designated area.

2. Instruct the student teams to determine the mass and volume of each of the 5 objects and record the measurements in the data table.

3. Instruct the students to input mass and volume amounts in the density formula and calculate the density of each of the 5 objects.

4. Instruct the students to complete the follow-up questions (see associated file).

5. While students are investigating, visit each group to check for understanding, accurate measurements and calculations.

Wrap-Up:

1. Collect all completed Data Analysis Worksheets.

2. Instruct the students to return lab supplies to a designated area.

3. Instruct the students to clean the laboratory areas.

#### Assessments

Students will complete the Data Analysis Worksheet showing evidence of their knowledge/understanding that different objects have different densities.

(See associated file)

Use a formative assessment to check accuracy of measurement and calculation.

(See associated file for sample answer key)

#### Attached Files

Worksheet and answer key for Density Destiny Investigation     File Extension: pdf