Density Lab

In the lab you will calculate the density of certain liquids and solids from measurements of volume and mass. You will also calculate the percent error of their density measurements by comparing what you find to their known densities.

In order to calculate the density you will use the following formula

D=m/v. Units are g/ml

Materials: Balance, graduated cylinder, beakers, distilled water, liquid samples, and solid samples.

Part I. Density of water

  1. Weigh and empty, dry graduated cylinder.
  2. Place approximately 20.0ml of water in the graduated cylinder.
  3. Record the exact volume of water. (Remember your estimated digit!)
  4. Find the mass of the water and the graduated cylinder
  5. Find the mass of the water
  6. Calculate the density using D=m/v

Data Table #1

Mass of the Graduated Cylinder
Volume of Water
Mass of Cylinder and Water
Mass of Water / Show Work
Density of Water / Show Work

Part II. Density of an unknown liquid

  1. Measure the mass of a 25.0ml cylinder
  2. Obtain a sample of unknown. Record the letter of the sample here:______
  3. Fill the graduated cylinder to about the 9ml mark with the unknown. Record the exact volume! (remember to have 1 estimated digit)
  4. Now weigh the cylinder again with the unknown liquid and record the mass.
  5. Do NOT pour the liquid down the drain. Place in waste container!

Data Table #2

Mass of Cylinder
Volume of Liquid
Mass of Cylinder + Liquid
Mass of Liquid / Show Work
Density of Liquid / Show Work

Part III. Density of an irregular solid.

a. Obtain an unknown solid from your teacher and record the letter here:_____

b. Mass the object.

c. Fill the graduated cylinder about ½ full with water. Measure and record the exact volume of water.

d. Carefully tilt the cylinder so no water spills out and GENTLY slide the metal into the water. This process is called water displacement.

e. Dry off and return the solid.

Data Table #3

Mass of Solid
Volume of water
Volume of water with solid
Calculate the volume of the solid / Show Work
Calculate the density of the solid / Show Work

Part IV. Calculating Percent Error:
(Observed Value - True Value)
Percent Error = ------x 100 =
True Value

Calculate the percent error for the water, liquid, and solid.

Denisty of water is 1.00g/ml

Find the density of the liquid matching your results on the overhead.

Find the density of the metal matching your results on the overhead.

Part V. Find the Thickness of Aluminum Foil

a. Using a 10. cm X 10. cm piece of aluminum foil, a meter stick or ruler, balance, math and your brain, find a way to determine the thickness of Al Foil

b .Express your answers in cm with two significant figures and in scientific notation

c.Express your answers in nm with two significant figures and in scientific notation

______

Part VI. Questions. Include the answers to the following questions in your lab report.

  1. Why is the accuracy of the balance used the investigation important? What affect would a less accurate balance have on your results?
  2. Explain how someone could look at the density of a sample, such as wooden duck, decoy, and predict whether or not it will float in water?
  3. Explain why water wings, a life jacket, or lungs filled with air make it easier for a person to float in water.
  4. When if first begins to rain or mist after a very long dry spell, roads become dangerously slick. Explain how this is a result of the comparative densities of the oil and water.