Are You Dense?Deborah McMurtrie, Ph.D.Bridget Coleman, Ph.D.Gary Senn, Ph.D.

University of South Carolina Aiken

Handouts for this session can be found on the AMLE2015 app

Density

• DENSITY is a physical property of matter; how tightly packed the molecules are

• The symbol most often used for density is ρ (the lower case Greek letter rho).

• The formula to calculate density is ρ = m / V

ρ = m / V

Density = Mass divided by Volume

What does that mean, exactly?

What is Mass?

• Mass is the amount of matter in an object.• Mass is how heavy something is (but without

gravity).• We measure mass in grams (g) and kilograms

(kg).

What is Volume?

• Volume is how much space something takes up.• Volume is the amount of 3-dimensional space

an object occupies.• We measure volume in milliliters (mL), liters (L),

cubic centimeters (cc), or cubic meters (m3).

Displacement

To find the volume of an irregularly shaped mineral (Garnet):

1. Fill the beaker with water up to the 10mL line.2. Carefully place the mineral in the water.3. Where is the water line now? 4. Subtract 10mL from the new measurement.5. That number is the volume of your mineral.

(Cubic centimeters)

Density of Minerals

• The minerals in your box all have the same VOLUME but each has a different MASS.

• Feel each mineral sample. Estimate the order from lightest to heaviest. Record your guess.

• Measure the MASS of each mineral and record your results. Compare.

• You will have 15 MINUTES for this activity!

Estimate the Order

Bauxite Galena

Fluorite Pyrite Garnet

Quartz

Take 4 Measurements

• You will have 10 MINUTES for this activity.• Six substances: Water, sand, salt, wood, iron

filings, and rubbing alcohol• You will take 4 measurements of one

substance: 25mL, 50mL, 75mL, and 100mL. Record your results for each on your data sheet.

Calculating Density

• Use your calculator to calculate the density of your substance.

• Density = MASS divided by VOLUME (g/mL)• Record your answers.

Graphing Density

• Your team will plot the data for ONE substance on a transparency.

• X axis: Horizontal (bottom) shows VOLUME • Y axis: Vertical (side) shows MASS• Connect the 4 data points by drawing a

straight line.• When you have finished, please bring your

transparency to the front.

Putting It All Together

• Density is the relationship between mass and volume.

• Graphing the data points shows this relationship.

• Water has a slope of 1.• Substances with a slope >1 will sink.• Substances with a slope <1 will float.

Related Middle Grades Standards

• Science: Density, Mass, Volume, Formulas, Minerals, Measurement

• Technology: Calculators, Measurement Tools

• Engineering: Inquiry, Engineering Design Process

• Math: Data Analysis, Graphing, Formulas, Slope, Measurement

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CEU Code:

GP-54

CEU CodeEarn Continuing Education Units (CEU) to maintain your teaching certification. Write down the CEU Code for every session you attend on the CEU card located in the back of the program book.