Organizing Information

Classifying

You may not realize it, but you make things orderly in the world around you. If you hang your shirts together in the closet, if your socks take up a particular corner of a dresser drawer, or if your favorite CDs are stacked together, you have used the skill of classifying.

Classifying is the process of sorting objects or events into groups based on common features. When classifying, first observe the objects or events to be classified. Then, select one feature that is shared by some members in the group but not by all. Place those members that share the feature into a subgroup. You can classify members into smaller and smaller subgroups based on characteristics.

How would you classify a collection of CDs? You might classify those you like to dance to in one subgroup and CDs you like to listen to in the next column, as in the diagram. The CDs you like to dance to could be subdivided into a rap subgroup and a rock subgroup. Note that for each feature selected, each CD only fits into one subgroup. Keep selecting features until all the CDs are classified. The diagram above shows one possible classification.

Remember, when you classify, you are grouping objects or events for a purpose. Keep your purpose in mind as you select the features to form groups and subgroups.

Sequencing

A sequence is an arrangement of things or events in a particular order. A sequence with which you are most familiar is the use of alphabetical order. Another example of sequence would be the steps in a recipe. Think about baking chocolate chip cookies. Steps in the recipe have to be followed in order for the cookies to turn out right.

When you are asked to sequence objects or events within a group, figure out what comes first, then think about what should come second. Continue to choose objects or events until all of the objects you started out with are in order. Then, go back over the sequence to make sure each thing or event in your sequence logically leads to the next.

Concept Mapping

If you were taking an automobile trip, you would probably take along a road map. The road map shows your location, your destination, and other places along the way. By looking at the map and finding where you are, you can begin to understand where you are in relation to other locations on the map.

A concept map is similar to a road map. But, a concept map shows relationships among ideas (or concepts) rather than places. A concept map is a diagram that visually shows how concepts are related. Because the concept map shows relationships among ideas, it can make the meanings of ideas and terms clear, and help you understand better what you are studying.

Network Tree

Look at the concept map about Protists. This is called a network tree. Notice how some words are circled while others are written across connecting lines. The circled words are science concepts. The lines in the map show related concepts. The words written on the lines describe the relationships between concepts.

When you are asked to construct a network tree, write down the topic and list the major concepts related to that topic on a piece of paper. Then look at your list and begin to put them in order from general to specific. Branch the related concepts from the major concept and describe the relationships on the lines. Continue to write the more specific concepts. Write the relationships between the concepts on the lines until all concepts are mapped. Examine the concept map for relationships that cross branches, and add them to the concept map.

Events Chain

An events chain is another type of concept map. An events chain map, such as the one on the effects of gravity, is used to describe ideas in order. In science, an events chain can be used to describe a sequence of events, the steps in a procedure, or the stages of a process.

When making an events chain, first find the one event that starts the chain. This event is called the initiating event. Then, find the next event in the chain and continue until you reach an outcome. Suppose you are asked to describe what happens when a sound wave enters your ear. An events chain map describing the steps might look like the one on page 818. Notice that connecting words are not necessary in an events chain.

Cycle Map

A cycle concept map is a special type of events chain map. In a cycle concept map, the series of events does not produce a final outcome. Instead, the last event in the chain relates back to the initiating event.

As in the events chain map, you first decide on an initiating event and then list each event in order. Because there is no outcome and the last event relates back to the initiating event, the cycle repeats itself. Look at the cycle map for photosynthesis and respiration shown above.

Spider Map

A fourth type of concept map is the spider map. This is a map that you can use for brainstorming. Once you have a central idea, you may find you have a jumble of ideas that relate to it, but are not necessarily clearly related to each other. By writing these ideas outside the main concept, you may begin to separate and group unrelated terms so that they become more useful.

There is usually not one correct way to create a concept map. As you construct one type of map, you may discover other ways to construct the map that show the relationships between concepts in a better way. If you do discover what you think is a better way to create a concept map, go ahead and use the new way. Overall, concept maps are useful for breaking a big concept down into smaller parts, making learning easier.

Making and Using Tables

Browse through your textbook and you will notice tables in the text and in the activities. In a table, data or information is arranged in a way that makes it easier for you to understand. Activity tables help organize the data you collect during an activity so that results can be interpreted more easily.

Parts of a Table

Most tables have a title. At a glance, the title tells you what the table is about. A table is divided into columns and rows. The first column lists items to be compared. In the table shown to the right, different magnitudes of force are being compared. The row across the top lists the specific characteristics being compared. Within the grid of the table, the collected data is recorded. Look at the features of the table in the next column.

What is the title of this table? The title is "Earthquake Magnitude." What is being compared? The distance away from the epicenter that tremors are felt and the average number of earthquakes expected per year are being compared for different magnitudes on the Richter scale.

Using Tables

What is the average number of earthquakes expected per year with a magnitude of 5.5 at the focus? Locate the column labeled "Average number expected per year" and the row "5.0 to 5.9." The data in the box where the column and row intersect are the answer. Did you answer "800"? What is the distance away from the epicenter for an earthquake with a magnitude of 8.1? If you answered "720 km," you understand how to use the parts of a table.

Earthquake Magnitude

Making Tables

To make a table, list the items to be compared down in columns and the characteristics to be compared across in rows. Make a table and record the data comparing the mass of recycled materials collected by a class. On Monday, students turned in 4 kg of paper, 2 kg of aluminum, and 0.5 kg of plastic. On Wednesday, they turned in 3.5 kg of paper, 1.5 kg of aluminum, and 0.5 kg of plastic. On Friday, the totals were 3 kg of paper, 1 kg of aluminum, and 1.5 kg of plastic. If your table looks like the one shown below, you are able to make tables to organize data.

Recycled Materials

Making and Using Graphs

After scientists organize data in tables, they may display the data in a graph. A graph is a diagram that shows the relationship of one variable to another. A graph makes interpretation and analysis of data easier. There are three basic types of graphs used in science - the line graph, the bar graph, and the pie graph.

Line Graphs

A line graph is used to show the relationship between two variables. The variables being compared go on two axes of the graph. The independent variable always goes on the horizontal axis, called the x-axis. The dependent variable always goes on the vertical axis, called the y-axis.

Suppose a school started a peer-study program with a class of students to see how science grades were affected.

Average Grades of Students
in Study Program

You could make a graph of the grades of students in the program over the four grading periods of the school year. The grading period is the independent variable and is placed on the x-axis of your graph. The average grade of the students in the program is the dependent variable and would go on the y-axis.

Average Grades of Students
in Study Program

After drawing your axes, label each with a scale. The x-axis lists the grading periods. To make a scale of grades on the y-axis, look at the data values. Because the lowest grade was 81 and the highest was 89, you will have to start numbering at least at 81 and go through 89. You decide to start numbering at 80 and number by twos through 90.

Next, plot the data points. The first pair of data you want to plot is the first grading period and 81. Locate "First" on the x-axis and locate "81" on the y-axis. Where an imaginary vertical line from the x-axis and an imaginary horizontal line from the y-axis would meet, place the first data point. Place the other data points the same way. After all the points are plotted, connect them with the best smooth curve. In this instance, the best smooth curve is a straight line.

Average Grades of Students
in Study Program

Bar Graphs

Bar graphs are similar to line graphs. They compare data that do not continuously change. In a bar graph, vertical bars show the relationships among data.

To make a bar graph, set up the x-axis and y-axis as you did for the line graph. The data is plotted by drawing vertical bars from the x-axis up to a point where the y-axis would meet the bar if it were extended.

Look at the bar graph comparing the masses lifted by an electromagnet with different numbers of dry-cell batteries. The x-axis is the number of dry-cell batteries, and the y-axis is the mass lifted.

Mass Lifted
by Electromagnets

Pie Graphs

A pie graph uses a circle divided into sections to display data. Each section represents part of the whole. All the sections together equal 100 percent.

Suppose you wanted to make a pie graph to show the number of seeds that germinated in a package. You would count the total number of seeds. You find that there are 143 seeds in the package. This represents 100 percent, the whole pie.

You plant the seeds, and 129 seeds germinate. The seeds that germinated will make up one section of the pie graph, and the seeds that did not germinate will make up the remaining section.

To find out how much of the pie each section should take, divide the number of seeds in each section by the total number of seeds. Then multiply your answer by 360, the number of degrees in a circle, and round to the nearest whole number. The section of the pie graph in degrees that represents the seeds germinated is figured below.

129	X 360 = 324.75 or 325°
143

Plot this group on the pie graph using a compass and a protractor. Use the compass to draw a circle. It will be easier to measure the part of the circle representing the nongerminating seeds, so subtract 325° from 360° to get 35°. Draw a straight line from the center to the edge of the circle. Place your protractor on this line and use it to mark a point at 325°. Use this point to draw a straight line from the center of the circle to the edge. This is the section for the group of seeds that did not germinate. The other section represents the group of 129 seeds that did germinate. Label the sections of your graph and title the graph.