When experimenting, a scientist must be able to record an immense amount of data and process those data into useful information. This is done by converting raw data into tables and charts. Then the data are graphed such that they can be interpreted by the public.
Data are the collection of individual observations or measurements recorded by scientists.
Graphs are visual representations of data. The graph you use depends on the type of data you have and what you are trying to show.
Tables/Charts
· Tables/charts are created for organizing data from raw measurement collections, later turned into graphs.
· The chart should show how a trend occurs over several occurrences (e.g., months, trials, categories) or over time.
Types of Graphs (see examples on back of this sheet)
· Pie graphs (or pie charts)
o Pie graphs are useful in showing percentages.
o Usually drawn as a circle, with “pie slices” representing the percentages that make up the whole (e.g., how I spend my day).
o Displays how categories are represented within a topic.
· Bar Graphs
o A bar graph is used to compare items that are discrete (not continuous; e.g., food categories, types of music).
o Usually drawn on a grid with X-axis and Y-axis.
o Useful when showing comparisons.
o It uses a series of columns to display data.
· Line Graphs
o A line graph shows trends and/or the best relationship between 2 or more variables that are continuous (e.g., student height, days it takes a chick egg to hatch).
o Usually drawn on a grid with X-axis and Y-axis.
o Along the x-axis (horizontal) is the independent variable (the one you changed).
o Along the y-axis (vertical) is the dependent variable.
o Drawn as one or more lines connecting a series of points (the points are your data points).
Constructing a Graph
1. Decide what type of graph would work best.
2. Decide on a scale for your graph.
· Must be as large as possible within the limits of the paper and still include all data.
· Select your scale with ease of locating points (e.g., multiples of 1, 2, 5, or 10).
3. Plot your points—remember, Y-axis = dependent variable!
4. Draw your bars (bar graph) or connect your points (line graph).
5. Be sure to have a title, labels for X- and Y-axes, and the proper sequence for accurate comparison (if applicable)
Examples of Graphs
Pie graphs
Bar Graphs
Line Graphs
What are these?