Environmental Data Analysis EESC BC 3017

Homework 2 - due Tu 9/22

Unit Conversions/Back-of-the-envelope calculations

1.) ( 10p) Benjamin Franklin dropped oil on a lake's surface and noticed that a given amount of oil could not be introduced to spread out beyond a certain area. If the number of drops of oil was doubled, then so was the maximum area to which it would spread. His measurements revealed that 0.1 ml of oil spread to a maximum area of ~430ft².

a) How thick is such an oil layer? Express the result in 'Angstrom'. The Angstrom is a convenient unit because lighter atoms such as hydrogen, carbon, and oxygen are on the order of 1 Angstrom in diameter. The answer is about 25 A. For the oil that Franklin used this is approximately equivalent to the thickness of one molecule. Please show how you get the result.
b) Franklin actually showed that 1 teaspoon of oil would spread to cover about 0.5 acre. Determine how many cubic centimeters there are in a teaspoon.

2.) (8p) Estimate he average spacing (distance) between H₂O molecules in liquid water by making use of two pieces of information: (a) liquid water has a density of 1.00 g/cm³, and (b) every 18g of water contain Avogadro's number (6.02x10²³) of H₂O molecules.

3.) (8p) Perform excercise #8 in the textbook, page 78 as discussed below (It is about baseball players). Print out the results as stated and hand them in:

An analyst has collected 2007 data including salary and batting average for major league players. Examine the data that have been collected.
Open Baseball.xlsx (in Chapter 2 folder) and

a.) Display only those players whose career batting average is 0.310 or greater. Print a list of those players.
b.) Add a new column to the worksheet, displaying the batting average divided by the player's salary and multiplied by 1,000,000.
c.) Sort the worksheet in descending order of the new column you created. What are the top ten players in terms of batting average per dollar? Print your results (just teh top 10).
d.) Examine the number of years played in your sorted list. Where do most of the first-year players lie? What would account for that? (Hint: What are some of the other factors besides batting average that may account for a player's high salary?)