Discovering Density

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Measure lines help visually represent data, an essential element for data analysis.

*Materials Needed:
Density Cubes
adding machine tape meter stick markers & pencils rulers
calculators 1 set of small vials (water, sugar, salt, air, sand) string
* per group of 4 students

Part I â€“ Regular-Shaped Objects (Density Cubes)

1. Begin by placing all density blocks on the table; mix them up.

2. Using â€śfelt weightâ€ť method, arrange the cubes from lightest to heaviest; This will serve as your prediction. Compare your predictions with others and discuss any variance.

3. Calculate the mass of each density cube and record it on a data table; do the same for the volume (l x w x h).

4. Work together (groups of 3-5) to create a measure line from 0-150 cm. Each centimeter will represent one gram. Tip â€“ mark each 5 & 10 cm increments, prominently.

5. Next, using the data table, place each cube at the appropriate location on the measure line. Tip – If additional space is needed on the measure line, place the cubes above/below the measure line and use an arrow to draw to the correct number.

6. Transfer the data from the table to the measure line; suggest writing the mass above the line with an arrow down to the line & volume below the mass. Beneath each mass and volume location, have students divide to calculate and label the density (see photo, below)

7. Challenge the students to locate and mark the â€śsink/floatâ€ť line.

8. Observe the visual representation of the data and generate/record statements which can be substantiated. Statements can be recorded on the measure line. Be prepared to share/defend your findings.

Notes:

Part II â€“ Irregular Shaped Objects (Vials)

1. Do not open vials; predict each substance.

2. Repeat felt weight method (see step 2 above).

3. Calculate the mass of each vial and record it on a data table.

4. Work together (groups of 3-5) to create a measure line from 0-35 cm. Each centimeter will represent one gram. Tip â€“ mark each 5 & 10 cm increments, prominently.

5. Next, using the data table, place each cube on the appropriate location on the measure line. Tip – If additional space is needed on the measure line, place the vials above/below and use an arrow to draw to the correct number.

6. Using the information on the data table and measure line, record answers to the following questions; complete additional steps to answer the questions, if needed.

Are the white substances the same? Explain

Find the actual mass of the contents of each vial without opening the lid. (Hint â€“ this may be different from the original calculated mass).

List the substances in order from the least dense to the most dense. Create statements about the density of the vials e.g. â€ś1 is denser than 3, but less dense than 4.â€ť

Assume the clear liquid is water. Calculate the volume (mL) of water in the vial

What other questions/tasks could be generated from this activity; focus the questions/tasks on data collection/recording analysis.

Adapted from: Crissman, S. (2011). Measure Lines. Science & Children, 48(5), 32-35.