Graphing in Physics

Graphing

• A way to display data that is collected in an experiment.

• They must be constructed accurately so data is understood.

• Three main types of graphs: line, pie and bar.

4 parts of a graph

1. Title & Axis labels

2. Independent variable

3. Dependent variable

4. Scales for variable

Parts of the Graph

Title- Depicts what the graph is about. It should be a statement placed above the

graph to help explain the graph. Axis labels give units and description of data.

The Independent Variable- it is the ONE thing in the experiment that is controlled by the experimenter. It usually concerns time, depth, or temperature. It is on the horizontal or x-axis.

Parts of a Graph

• Dependent Variable –is the variable that is directly affected by the changes in the independent variable. This variable is placed on the vertical or Y-axis.

• Scales for each variable- In order to plot a graph you must set a scale to include all the data points. The scale will start with 0 and climb in equal intervals such as 2,5,10 etc. The scales for the x and y axis can be different.

Graphing Scientific Data

• Use the best fit line. You don’t connect dot-to-dot but draw a line that goes through most of the points.

• Interpolation- is used when you get approximate values that are between points.

• Extrapolation- is used to approximate values beyond the range of the data.

Accuracy & Neatness in graphing

• To convey the data correctly all parts of the graph must be accurate and neat.

• Rulers and graph paper should always be used.

• Graphs must fit the graph paper you can adjust the scale so they fit.

• A graph is incomplete if the title and axis labels are missing.