GRAPHING IN SCIENCE

Graphing Guidelines Descriptive title Label each axis. Include Quantity and Units Choose an appropriate range Maximize your graph area a. Label each axis at regular increments b. Use convenient increments 5. Plot points clearly and accurately. 

Variables Independent – The data you know ahead of time, X-AXIS, the variable that is experimentally varied Dependent - – What you are trying to find out, What is observed, Y-AXIS - It’s dependent on the independent variable

Dependent Variable Independent Variable

Example Place a D for dependent and an I for Independent below the correct variable. Then label the axes on the graphs. 1. Candy and Cavities Candy – Cavities - I D Cavities Candy

Example Place a D for dependent and an I for Independent below the correct variable. Then label the axes on the graphs. 2. Grades and Hours of Studying Hours of Study – Grades - I D Grades Hour of Studying

Best Fit Line A best fit line shows what you would expect to happen if you gathered more data than you have It’s the one, straight line that is closest to all data points Does not necessarily connect all data points Like an average of all the points

Drawing a Best-Fit Line

GRAPHING RELATIONSHIPS

DIRECT RELATIONSHIP 5 As one variable increases, the other _____________ Line will slant ______ Y 4 Increases 3 Up 2 1 1 2 3 4 5 X

DIRECT RELATIONSHIP Examples Human Population versus Pollution As the population increases, pollution increases

INDIRECT or INVERSE RELATIONSHIP 5 As one variable increases, the other _____________ Line will slant ______ Y 4 Decreases 3 2 Down 1 1 2 3 4 5 X

INDIRECT or INVERSE RELATIONSHIP Example Elevation versus Air Temperature The higher up you go in the sky, the air temperature is colder (decreases)

CONSTANT RELATIONSHIP 5 As one variable increases, the other _____________ Line will Y 4 Stays the same 3 2 Go across or up and down 1 1 2 3 4 5 X

CONSTANT RELATIONSHIP EXAMPLE Hours in the day Always stays at 24

CYCLIC RELATIONSHIP USED TO PREDICT CHANGE 5 As one variable increases, the other_____________ Line will Y 4 Increases then decreases then increases, etc 3 2 1 Up, down, up, down, etc 1 2 3 4 5 X USED TO PREDICT CHANGE

CYCLIC RELATIONSHIP Tides