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.
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.
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.
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.
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.
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.
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
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.
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
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 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.
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 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.
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.
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
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.
and Using Tables
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
of a Table
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.
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.
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.
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.
and Using Graphs
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 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.
a school started a peer-study program with a class of students to see
how science grades were affected.
Grades of Students
in Study Program
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.
Grades of Students
in Study Program
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.
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.
Grades of Students
in Study Program
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.
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.
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.
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.
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
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.
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.
X 360 = 324.75 or 325°
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.