Size of an Oil Molecule

[Logan Clendenin]

Scientifically oriented question – What is the estimated size of an oil molecule?

Evidence – Volume of the oil drop: 4/3π(.25)^3=.065 mm^3. Area of the spread oil drop: Radius being 110 mm because the diameter is 220 mm. A= π(110)^2 =38000 mm^2 when rounded to least number of significant figures. The thickness of the oil layer is the volume of the oil drop divided by the area of the spread oil drop. Since the height is the oil patch thickness which is the size of the oil molecule, .065 mm^3/38000mm^2=1.7 x 10^-9 m.

Explanation- By calculating the volume of the drop, 0.065 mm^3, and the area of the spread out drop,38000 mm^2, we could easily determine the thickness of the oil, 1.7 x 10^-9 m, by dividing the volume and area. Since the thickness of the oil is the size of the molecule, the size of the oil molecule is 1.7 x 10^-9 m. The oil molecule spreads across the water until it forms a monomolecular layer only a molecule thick, typically 2 nm.

Connection- This lab shows the importance of being precise in measurement as well as using significant figures. The formulas we used in this lab as well as many other formulas will be used all year long in different labs to calculate measurements.

Communication –The most practical way to communicate this information would be to show the mathematical equations used to get it and examine them to determine if the results are correct. 

Reflection – Other students have put similar things to me because i feel like the majority of us have the same learning style and view things the same way. This lab has helped me think more critcally on the subject of accurate measurements and how they are important to justify your results in an experiment.