Bar graphs compare items and are a visual way to represent research findings. Graphs are constructed along an X, or horizontal axis and a Y, or vertical axis. The X axis is labeled with the various objects that are compared. The Y axis is labeled using a unit of measurement. Bar graphs can be used to display the average speeds of the fastest land animals including cheetahs, gazelles, antelopes and horses. The bars represent the various animals while the bar heights are constructed based on the average speed. Students can easily see that the higher the bar, the faster the animal.
Line graphs can show changes over time. Line graphs can compare the average temperatures from month to month in a specific location. They can also show the growth of a plant from week to week. The units of time are displayed along the X axis. The units of measurements are displayed along the Y axis. Points are plotted to show the height or temperature from one time period to the next. A line connects the points along the graph. Students observe the slope of the line to compare differences over time.
A circle graph shows different parts or classifications of a whole unit. The sections of the circle correspond with the size of each group in relation to the whole. Comparisons of students' blood types can create the sections and sizes in a circle graph. The experimenters can survey the students to determine their blood type. The number of students for each type is converted to a percentage of the whole class. The sections and sizes correspond with the percentages. Larger sections indicate the more common blood types while smaller sections indicate less common blood types.
A pictograph displays symbols or images that represent specific data amounts that are measured or observed. A key is used to determine the numerical value of each symbol. A pictograph can be used with a bird watching activity. Students can record the number of different types of birds for specific species that are observed over a period of time in a designated location. A single bird symbol stands for a specific number such as two, five or ten observed birds. A partial symbol stands for a number smaller than that unit key. The graph displays the total number of birds in each species that were observed.