Lines, Lines and More Lines...

http://edweb.sdsu.edu/courses/EDTEC596/Units/Dive/lines.html

Introduction

In preparation for our unit on diving, we will need to brush up our skills on graphing equations and lines. We will be seeing how this graphing thing applies in real life through the sport of diving.

The Task

The first of the activities, as we said, is to review equations and their graphs.

Plot and graph an equation.
You will need to identify slope, x- and y-intercepts, and y-form linear equations. The second part of this task is an activity that will help you convert from this seemingly hooey mix of x's and y's to a more realistic understanding of just what graphing really is. After the activity, you'll be asked to answer these questions in your groups:
What happens to the slope of each line as you go from running to walking? How about from walking to running?
What would happen to the slope of the line if you stood still?
What would it mean if the graph of some portion of the line were vertical?
Do you think that this graph is an accurate representation of the formula D=(r)(t)?

Resources

You will need some graph paper, a ruler, as many stopwatches as are procurable (for the class) and the students should be dressed for the outdoors. A tape measure for distance is required.

The Process

As we said in the beginning, we were going to practice graphing first.

On your own, graph y = 3x + 1 and y = -x + 3 on your paper.
In your groups, make sure you discuss the following:
- Slope of the equation
- x-intercept
- y-intercept
- Is the slope of the equation positive or negative?
If you don't remember what a term means, ask someone or look it up. You will have about 10 to 15 minutes to do this.
Once you are done, we will discuss it in class. Then you'll get into groups of four and we move outside.
Each team choose one of the running spots marked off.
Each student will be timed for 10 seconds. You may walk or run any portion or all of the 10 seconds, but you must count 10 seconds. When the time is up, measure the distance travelled. Record this information. If you stopped at any time before the time is up, record the time you stopped. For example, if you stopped running after 6 seconds, note this.
Each student will do this twice, but you CAN'T do the exact same thing you did the first time.
Print out this chart so that your group can work on it.
You'll also need to print out the graph if you should need help setting it up.
Record all of this data and come inside and we will record the data on a chart and graph it. Remember to answer the questions that I gave you in The Task section.

Evaluation

Students will be required to view 3 charts similar to the one they just created and write a small scenario that could be represented by each. Remember that we're graphing Distance and Time. One of these graphs is NOT possible. Determine which one and tell why. You recieve 5 points for identifying the illegal graph. For the other two, each slope in the graph needs to be represented in your scenario. Each slope is worth 2 points. Click here for an example.

Conclusion

You now have a better understanding of graphs and how this graphing thing will be used in real life. You should, by now, have an understanding that a graph isn't just x's and y's, but represents a rate of change or a relationship between two rates or items.

Last updated May 18, 1997. Return to the Recreational Diving Page

Based on a template written by Bernie Dodge.