How many atoms thick is aluminum foil?

Asked by: David A. Biche

Answer

Approximately 193,000 atoms thick.

This is a fairly rough estimate, from classroom data. We took squares of aluminum foil, measured the surface area and mass. By dividing the mass by a known density value, we obtained the volume of aluminum foil in our sample. By dividing that by the surface area, we found the thickness of the aluminum foil in cm. (The value was 2.86 *10^-3 cm.) The value converted to be 2.86*10^5 angstroms. Each aluminum atom is about 1.48 angstroms, so we can divide. Assuming that each aluminum atom is stacked directly on another one (which they aren't, but we can't measure without making this assumption), we come up with 1.93 * 10^5 atoms thick. There may be different types of aluminum foil, but these results were fairly precise among our class's data, so I hope it is at least somewhat helpful.
Answered by: Andy Clemons, High School Student