1. Graphs in Physics PowerPoint #4

2. A graph is… A convenient way to show data.

3. 3 Types of Graphs A bar graph is used to show relationships between groups. The two items being compared do not need to affect each other. It's a fast way to show big differences.

4. A circle or pie graph is used to show how a part of something relates to the whole. This kind of graph is needed to show percentages effectively.

5. A line graph is used to show continuing data; how one thing is affected by another. It's clear to see how things are going by the rises and falls a line graph shows. This kind of graph is needed to show the effect of an independent variable on a dependent variable.

6. Independent & Dependent Variables Independent Variable: (controlled by the experimenter) Goes on the X axis (horizontal) Should be on the left side of a data table. Dependent Variable: (changes with the independent variable) Goes on the Y axis (vertical) Should be on the right side of a data table.

7. Using A Graph to Find Values: Interpolation predicting data between two measured points on the graph Extrapolation extending the graph, along the same slope, above or below measured data.

8. What does the graph look like? What is the generic equation of the trend line? write this: y = m(x) + b write this: y = b write this: y = m(x 2 ) + b What is the b value? b is the y intercept, the number on the y axis that intersects with the trend line. What is the slope (m) of our trend line? Use this equation to solve for slope: m = 0 No slope Use this equation to solve for slope: What is the mathematical equation (model)? y = __(x) + __ Fill in the __ with the slope value and the b value y = __ Fill in the __ with the b value. y = __(x 2 ) + __ Fill in the __ with the slope value and the b value

9. Using Excel to Graph Information: Put your numerical x data in the a column and your numerical y data in the b column. Leave out any words. Highlight your data

10. Click on the chart (graph) wizard Choose xy scatter with no lines, then click on next

11. Make sure the series is columns, then click on next. Put in correct title, value x and value y, then click on the gridlines Tab.

12. Click on the value (x) major gridlines box, then click on the Legend tab Unclick the show legend box and then click on finish

13. Double click in the plot area then change the plot area to none. Then click on OK. Go up to chart and slide down to Add Trendline.

14. There are different types of trendlines, in this class you will almost always use a linear trendline. Usually it is the default selected trendline. Then click on the Option tab. The option tab allows you to do a number of things. Click the display equation on chart box, set the intercept(b value) to 0 and click the box. You can set the b value to anything you need. Lastly, have the trendline Forecast Backward the exact number equal to your first x value. In this graph the first x value is 1. Then click OK

15. Right click on the trendline, you will see a Format Trendline choice, slide down to it then left click on the Format Trendline. For some reason the program now gives you a third tab called Patterns. You want to make the style of the trendline dashed. In this tab you can change the color and weight of the trendline as well. Then click OK

16. Click in the upper left hand corner somewhere in the chart area that is out of the graph. You are trying to get the black squares appear around the entire chart area. Go up to the top and choose format then slide down to Selected Chart Area

17. Click on the Font tab and then unclick the Auto scale box in the bottom left hand corner. In the tab you can change the font of the graph change the color and a number of other things. Feel free to personalize your graph.Then click OK

18. Slowly double click in the chart title area. You should see a cursor appear where you double clicked. Now use the arrow keys on the keyboard to get the cursor all the way to the right of the title and then touch enter on the keyboard. You have just created a new line in the title which you can put your name and period on.

19. Go to print preview and make sure you are only going to print the graph. If you get the data table and the graph, go back to the graph and make sure that the black squares appear around the chart area, you do this by clicking anywhere on the chart. Now go back to print preview and you should just have the chart.