Bay Link Lesson Plans
Natural Inverse Variation
(For Graphing Calculator)
Send questions and comments concerning this lesson to author
Stephany Faulkner, Indian River High School, Chesapeake, VA.

Grade Level:
Algebra 2 - TI-81/-82/-83 Proficiency needed


Standards:
A11/T.3 and All/T.20


Objectives:
To graph two different pieces of data from the Chesapeake Bay and to begin to see a Natural Inverse Variation occurring.


Procedure:
Divide your class into groups no larger than five students. Students will enter of
Temperature data and Oxygen data into the calculator (preferably the TI-82/83).

Enter as follows:

STAT -> EDIT

Several columns appear, labeled L1 , L 2 , L3, etc.

L1 = months of temperature (1-12)
L2 = temperature for one year
L3 = months of oxygen (1-12)
L4 = oxygen values for one year

After all data is entered correctly, preview the format/range of the graph as follows.

WINDOW -> FORMAT

Make sure everything is highlighted to the left.

WINDOW

Xmin = 0
Xmax = 13
Xscl = 1

Ymin = 0
Ymax = 26
Ysc1 = 2

To Create the scatterplot:

2nd Y= --> ENTER

(NEW MENU APPEARS)

Make sure ON is highlighted
Type: First box is highlighted
Xlist - L1
Ylist - L 2
Mark - ¥ (First)

Now
2nd --> Y = --> 2

Repeating above with second set of data.

Type: First box (on) is highlighted
Xlist - L
Ylist - L
Mark - + (second)

GRAPH for Temperature
GRAPH for Oxygen
GRAPH for Both

The data has just been graphed as a scatterplot. An analysis of the data should begin.

Look at the Temperature and Oxygen.
  1. What happens in January .?.

    The Temperature is __________

    The Oxygen is __________

  2. What happens in July .?.

    The Temperature is ________

    The Oxygen is ________

Can you figure out what is occuring?

Can you give possible reasons why this may be happening?

Where do you think the fish will be in the summer?


Chesapeake Bay DATA

Temperature & Dissolved Oxygen - 1986-1990


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