1.    Greenhouse gases.  The burning of fossil fuels (oil, coal, natural gas) releases carbon dioxide into the atmosphere.  Carbon dioxide is known as a greenhouse gas because it tends to trap heat in the atmosphere, causing global warming.  In 1995, the United States emitted about 1.4 billion tons of carbon (as carbon dioxide) into the atmosphere. China was second largest contributor, emitting 850 million tons.  US emissions were increasing at 1.3% a year, while Chinese emissions were increasing at 4% a year. Assuming these growth rates continued determine the year when China will exceed US in carbon emissions.  Create a table with a simulation of the growth in CO2 to answer that question.  Round the numbers in each cell to 3 decimal places.  Copy into your Word document the year and CO2 amounts when China exceeds the U.S. production. 

2.  Chicken Bacteria.  The information given below was found on the label of a package of chicken.

Bacteria Count on Chicken
(per square centimeter when refrigerated at 40º F)

a.  By using percentage changes, show that the above data is exponential.  What is the percentage increase in bacteria each day?

b.  It is also noted on the label that at 40º F, the bacteria double in number every 6 hours.  Make a new table showing the bacteria count every 6 hours.  To get you started, you table should look like this:

You should continue your hours column to 120 hours.  Paste your Excel table in your word document.

c.  What is the percentage increase in bacteria every six hours?

3.    Doubling time.  Doubling time refers to the amount of time required for amount to double.  In problem 2, the doubling time was 6 hours.  Let's examine how doubling times are related to the percentage rate of growth. 

Create a simulation examining the growth of an amount at three different rates of growth: 3%, 5% and 7%.  Start each with a beginning amount of 100 and carry the simulation through 80 time periods. 

a.    In which time period did the amount hit 200, 400 and 800 at 3% growth? 

b.     In which time period did the amount hit 200, 400 and 800 at 5% growth? 

c.    In which time period did the amount hit 200, 400 and 800 at 7% growth? 

d.    What seemed to be the doubling times for each of the percentage rates of growth?  Compare that amount to 70 divided by the rate of growth.