One of the more useful skills that you can gain is to become adept and order of magnitude estimation (you will amaze your friends and maybe even win money from them ...:) )

This skill will also allow you to think our your feet better and to develope a more quantitative view of any problem. This is probably the most useful skill you can learn in this class.

Today we will try a bunch of practice problems to hone our skills.

The basic rule set for doing an estimation problem is

1. Understand the problem and what is being asked

2. choose a set of consistent units

3. try to scale up a local example that your familiar with

4. devise an estimation plan

5. turn the crank on your plan

6. perform a reality check on your result this important step is often completely forgotten

To begin with, I will work out the procedure for estimating the number of grains of sand on all the world's beaches. This will give you an example of how to approach these problems.

Estimation questions: (some of these are easy, some are very hard) No fair Googling for the answers in class!

The goal of this exercise is to compare answers and methodologies for arriving at these various estimates. Answer each question first in the worksheet and then publish the answer to that question. When all results are in, we will move to the next question.

Fill in your estimates in this worksheet The worksheet has been structured along the lines above.

1. How many gallons of gas are used in US automobiles on a daily basis?





2. How many square inches of pizza are consumed by all the students at the University of Oregon during on academic year?





3. Suppose that in a 24 hour period it rained 2 inches throughout the entire Willamette valley. Given that the density of water is 1 gm/cm³, what is the total mass of water that fell. Express you answer in tons.





4. In the 1989 Loma Prieta earthquake in California, approximately 2 million books fell off the shelves at the Stanford University library. If you were the library administrator and wanted to hire enough part-time student labor to put the books back on the shelves in order in 2 weeks, how many students would you have to hire? (You may assume that the books just fell off the shelves and got a bit mixed up but books in different aisles did NOT get shuffled together.)





5. The Federal Budget Deficit is approximately $100 Billion this year. Compare this to what we spend on what we eat by estimating the total amount US consumers spend on food in grocery stores, markets, and restaurants in one year.





6. Estimate the total number of sheets of 8.5 x 11 inch paper used by all the students at the University of Oregon in an academic year. Now assume these sheets are stacked on top of each other (the thickness of an individual sheet is 0.001 inches). How tall is the stack and in terms of volume, how many equivalent 100 foot high Douglas Fir trees does this represent.





7. How many gallons of water are used annually for washing clothes in the US?





8. How many total miles does the United STates Interstate Highway system contain?





9. How many Douglas Fir Trees are there in Oregon (this one is very hard)?