What is the size of an oil molecule?

[Hunter Reichenbach]

Scientifically Oriented Question- What is the size of an oil molecule?

 

Evidence- Using the radius of the oil drop, .25 mm, we calculated volume of the oil drop to be .06 mm^3. The radius of the oil drop was 4 mm. Using the formula Area= πr^2, the area of the spread oil drop was 50 mm^2, and the thickness of the oil layer was .01 mm; together which equals 1x10^-5 m. Therefore, the size of the oil molecule is about .01 mm.

 

Explanation- The volume of a sphere is (4/3) πr^3, and the oil drop is a sphere, which is why the formula can calculate the volume of the oil drop. Since the radius of the oil drop is .25 mm, its volume= (4/3) π(.25)^3. Meaning its volume= .06 mm^3. The oil drop spread out after it hit the surface of the water and formed a circle. Since the area of a circle is  πr^2, the area of the oil layer=  π(4)^2= 50mm^2.The height of the oil layer can be determined from the formula for the volume of a cylinder, which is  πr^2h, where H=height and R=radius. So, we plugged in our previous calculations of the area and the volume to determine the height, and we got the equation: 50H=.06. To find the value of H, we divided .06 by 50 and got .01mm as the height. To simplify the calculation, we used the train tracks method to convert .01mm to meters: (.01 mm/ 1) x (1 cm/ 10 mm) x (1 m/ 100 cm). So, .01 ÷ 10 ÷ 100 = 1x10^-5 m. Therefore, the approximate size of an oil molecule = 1x10^-5 m.

 

Connection- This lab shows the importance of knowing how to use and implement significant figures into our equations. It shows that measuring and calculating using significant figures is essential because it makes for the results of experiments and simple calculations to be the most precise and accurate as they can be. This lab also showed the importance of being able to use different formulas and figure out calculations. Both of these tasks are important because we will be using them all year long. In the real world, significant figures and formulas are used in many occupations; for example, the medical field. If calculations are done wrong or significant figures are used improperly, something horrible could happen. Someone could even lose their life if a dosage is to small or large.

 

Communication- The best way to communicate this information to the public would be to make a table showing the formulas, measurements, and calculations so people could visually see the evidence we gathered and how the measurements were used to find the area, volume, and size of the oil molecule. I would show my mathematical work somewhere near the table so people could easily see the method by which I calculated the values.

 

Reflection- Most of the other students have written about the same things about the oil molecule. Several students, including I, have found that these measurements and calculations using significant figures could be used in the medical field. However, conclusions to this lab have varied among some students because some students may have had bigger oil layers than others, so their calculations would be different. However, the major components of each student's findings are justifiably similar.