Environmental Data Analysis BC ENV 3017

Homework 1 - due Th 9/23

Unit Conversions

1.) ( 20p) 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 between H2O molecules in liquid water by making use of two pieces of information: (a) liquid water has a density of 1 g/cm3, and (b) every 18g of water contain Avogadro's number (6.02x1023) of H2O molecules.

3.) (8p) The  consumption rate of water in New York city is 1.5 billion gallons per day. What fraction of the average discharge rate of the Hudson River (12 km3/y) does this represent?

Back of the envelope calculations

4.) (10p) About what fraction of a cubic centimeter of rubber is worn off an automobile tire with each revolution of the wheel?

5.) (10p) How many dentists are there in New York City?

Questions related to the readings

6.) (5p) Summarize in ~ 5 sentences why midwestern states have some influence on the tropospheric ozone concentrations in New York, what EPA is doing about it, and what the current political status is.

7.) (5p) Summarize in ~5 sentences the negative effects of tropospheric ozone on humans etc.