Name Date Class

The Thickness of Aluminum Foil

All matter is made of atoms. A collection of only one type of atom is an element. Aluminum is an element. One use of aluminum is to make foil, which is used to wrap food for storage. Large numbers of aluminum atoms are found in any sample of aluminum metal. Because each aluminum atom is extremely small, a sample of aluminum foil is many atoms thick.

In this activity, you will calculate the size of an aluminum atom by determining the thickness and mass of a piece of aluminum foil.

OBJECTIVES

  1. Measure, indirectly, the thickness of aluminum foil.
  2. Estimate the number of aluminum atoms that give the foil its thickness.

MATERIALS

Inline Figure

balance

metric ruler

aluminum block

100-mL graduated cylinder

piece of aluminum foil

scissors

string

PROCEDURE

  1. Before you begin, form a hypothesis regarding the directly observable data that are necessary to compute the thickness of aluminum foil. Write your hypothesis under Data and Observations.
  2. Use a balance to determine the mass of a block of aluminum metal. Record the mass of the block in the data table.
  3. Fill a 100-mL graduated cylinder with water to the 50 mL mark.
  4. Tie a string to the block of aluminum and lower the block into the water until it is completely immersed. Record the new volume of water.
  5. Calculate the volume of the aluminum block by subtracting the initial volume of water from the volume of water with the aluminum block in it. Record in the table the volume of the aluminum block.
  6. Remove the block from the cylinder, dry the block and return it to your teacher.
  7. Cut a piece of aluminum foil. The piece should be approximately 12 cm × 12 cm. Measure the exact length and width of the foil and calculate its area. Record the area in the table.
  8. Use a balance to determine the mass of the aluminum foil. Record the mass.

DATA AND OBSERVATIONS

Hypothesis:________________________




Mass of aluminum block ______g
Volume of water in graduated cylinder ______mL
Volume of water with aluminum block ______mL
Volume of aluminum block ______mL
Width of the piece of aluminum foil ______cm
Length of the piece of aluminum foil ______cm
Area of foil (l x w) ______cm2
Mass of aluminum foil ______g

ANALYSIS

  1. What is the purpose of the block of aluminum?



  2. What is the density of aluminum? (Density = Mass of aluminum block/volume of aluminum block)



  3. What is the volume of the aluminum foil? (Volume of foil = Mass of foil/Density of aluminum)



  4. What is the thickness of the foil? (Thickness of foil = Volume of foil/Area of foil)



CONCLUSIONS

If one aluminum atom is 2.5 × 10-8cm in diameter, how many atoms thick is the aluminum foil?





EXTENSION AND APPLICATION

Compare the diameters of magnesium, calcium, strontium, and barium atoms. What is the relationship between the elements' atomic numbers and the diameters of their atoms? Why do you think this is so?