Ask students if they know anyone who has never been on the internet. Then tell them that only 15 years ago most people in the world had never heard of the internet. Have a short class discussion about the factors that would cause such rapid growth, and other examples of that kind of growth (for example, cellphones, popularity of musical performers or groups, etc.).
Explain that one of the factors that has made the growth of use of the internet possible is the ability to transmit lots of information rapidly over long distances, and show Futures Channel Movie #5003. After the movie is over, display a graph of the following data:
Year Terabytes per month
1990 1
1991 2
1992 4.4
1993 8.3
1994 16.3
Explain to students that a terabyte is very large quantity of information, and that the graph you are displaying shows how many terabytes were carried on the Internet for the month of December for the first 5 years of the 1990’s.
Ask students if the graph seems to be linear, and guide discussion to agreement that it is not. Display a chart of the data for the graph, and ask students to work in pairs for a few minutes to see if they can find any pattern in the data. Share answers, and guide class discussion to the observation that the number of terabytes seems to roughly double every year.
Explain that this kind of relationship between variables is called an exponential function, and that such functions are very useful for describing some situations in which things grow, and also some situations in which things decrease. Tell students that they will learn how to work with exponential functions in this chapter. |
