# Working with Great America Data

To work with your data, install Logger Pro if you have it available in your school or use a computer that has Logger Pro installed. If not, you can go to the Vernier website and download a 30-day free trial version. Install that program and then use it to open your files. Follow the suggestions below.

Here are some suggestions for you that may help you get more out of the data you've collected at Great America. The same instructions apply whether you are using a PC or a Mac. Logger Pro has many features built in to make the display of your data better.

## Acceleration vs. Force

The units for the data you collected are N/kg. This emphasizes the nature of what you were feeling while you were riding. Gravity is normally 9.8 N/kg, or approximately 10 N/kg. So by dividing the values you get by 10, you will see how many times the force of gravity the force was that you felt, or how many g's.

But the units are called acceleration! Yes, but if you work out basic units, N/kg is the same as m/s2. In reality, though, we are measuring the force on a tiny mass unit inside the device. The force is proportional to the acceleration that it is undergoing, or that you underwent. Focus on the force, even though we call the device an accelerometer.

Think this way: What kinds of forces did I feel at various places on the ride? How large were those forces? Why did I get those forces of those sizes at those places?

## Title the graph

You can put a title on a graph by double-clicking anywhere in the field of the graph. Simply type in the title you wish to use.

## Identify Axes

If we didn't already do this, change the names of the columns in your data table by double-clicking on the old label and typing in the new one as follows:
 New Meaning Vertical Up and Down Lateral Side to Side Longitudinal Front or Back
After a change in direction from California's Great America, we are carrying the WDSS units in a DataVest. We know which axis is which because of the orientation of the unit. The x-axis is what we normally call "Vertical" with positive being upward, the y-axis is what we call "Lateral" with positive being to the right, and the z-axis is what we call "Longitudinal" with positive in the forward direction.

## Smoothing Data

Go to Data, then choose New Calculated Column. Title it "Smooth Vertical" and give it units of "N/kg". With your cursor in the space labeled "Equation", use the drop-down menu labeled "Functions" to choose "smoothAve". Note that the cursor stays inside the parentheses. Now use the drop-down menu labeled "Variables" to choose "Vertical". Finally, click on the tab "Options" and choose a good color using the scroll window on the right. By clicking [Done], you will have created a new column in your data table for smoothed vertical force data.

Repeat to create columns for "Smooth Lateral" and "Smooth Longitudinal". You can also create a "Smooth Altitude" column, too.

To see the smoothed data on a graph, click on the label for the y-axis, then choose the data you wish to see. You may wish to click the button with the capital A in it, Autoscale, to expand or contract the data to fit the screen better. It's often best to look at the smoothed data as details can sometimes get lost in the jumpiness of the raw data.

Go to Page on the menu bar and choose Auto Arrange. This will make the graphs larger, filling in any extra space you created.

## Printing

If you want to print out a portion of the data table plus the two graphs, all you need to do is make sure none of the windows is selected (click in an empty space on the screen). Go to File > Page Setup to arrange for Landscape printing. Then go to File > Print.

If you want to print out a graph go to File > Print Graph.

## Word or Powerpoint

If you want to put your graph into Word or Powerpoint, or any of the modern word processors or presentation programs, simply click near the top of the graph, selecting it. Then go to Edit > Copy. Now switch over to your other program, position your cursor, then go to Edit > Paste. The graph should appear in the new application just as you saw it in Logger Pro. It may need to be re-sized to fit your document in some programs.

## Making Annotations

If you wish to point out special places on your graph, click on the graph to select it. Then go to Insert > Text Annotation. A box will appear on your graph inside of which you can type your information like "When we were upside down". Click outside the box you were typing in, then move the cursor back into the box until it becomes a hand. Using a left-click and holding it down, you can re-position the box on the graph. Then grab the end of the line that comes from the box and move it until it touches the graph where you want.

Once you have made an annotation like this, when you copy the graph and paste into another program, the annotation will go along with it.

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There are lots of other not-so-secret secrets for working with Logger Pro and your data. Be sure to save the changes you made after you're done.

Again, thanks for using the Electronic Data Center, and good luck with your work on the amusement park data.