Scientific Graphing Objective: To be able to graph results from an experiment and interpret the results

Data Tables Independent Variable (IV) Dependent Variable (DV) Observations from an experiment are organized into a data table. The Independent Variable is always located on the left side of the data table and the Dependent Variable is on the right.

How to set up your graph 2. Label axis's: x-axis (horizontal axis) with your independent variable (IV) y-axis (vertical axis) with your dependent variable (DV)

Setting up your scale Scale: Spread the graph so that data will cover most of the page but NEVER allow the data points to extend past the last square on the graph page. Step 1: Determine the variable range Subtract the lowest data value from the highest data value for each variable (DV and IV). Example: Range of seeds that germinated : 10 (highest #) - 0(lowest #) = 10 Step 2: Determine the scale of the graph Range / # of lines on the graph Example: 10 seeds / 20 lines = .5 seed per line, which is 1 seed every 2 lines, because we cannot have .5 seeds. (always round up) Step 3: Number each axis

Plot your data: Use a different color dot for the control and experimental points Draw the Line of the Graph: Draw the line or curve that best fits the data points. Most scientific graphs are not "connect-the-dot" graphs. The purpose of the graph line is to show the general trend of the data. The line does not necessarily have to touch every data point.

Title: Should reflect your hypothesis Title: Should reflect your hypothesis. (place this in an open space on the grid) Example formats: The dependence of (insert your dependence variable) on (insert your independent variable). The effect of _____________ on _______________. Key: If a graph has more than one set of data, a "key" must be included to identify the different lines. Like the title, a graph key should be placed in an open space inside the grid - not in the margin of the paper. If the graph only has one set of data, a key is not needed

Interpreting Graphs Remember that a scientific graph is usually a straight line or a curved line - not "connect-the-dots". Each type of line represents a certain relationship between the two variables. Straight lines - indicate a direct relationship between the two variables. Every time the Independent Variable changes by a certain amount, the Dependent Variable changes by a certain amount. Curved lines - indicate a changing relationship between the two variables. Every time the Independent Variable changes by a certain amount, the Dependent Variable changes by different amounts