A picture perfect process

Teaching Pre K-8, Oct 1994 by Leyden, Michael B

Picture students actively engaged in gathering data and expressing their findings in colorful charts. The science process featured this month is graphing, and the goal is to illustrate how this s can be applied to many curriculum areas.

Specifically, we'll see how graphing concepts can be used when you're teaching art, language arts, history and social studies. Science? Well, it's never very far away. Often, it takes only a few questions before "traditional" science becomes the focus of the lesson.

Graphs are diagrams that organize and display data. They can be thought of as a kind of visual shorthand. Rather than employ a long narrative account to show relationships among quantities, we use a graph. A graph can get the point across in the blink of an eye because, as we've heard so often, a picture is worth more than ten thousand words.

Ninja artists. This activity is ideal for introducing students to graphing. Not only does it involve making a timeline--the simplest of graphs because only one variable is being charted--but it also involves the Ninja Turtles. Actually, it only involves their names, but that will probably be enough to whet the students' interest.

Most children know the turtles' names, but few realize that these crime-fighting, pizza-eating reptiles were named after four of the Renaissance's greatest artists: Donatello (1386-1466), Michelangelo (1475-1564), Raphael (1483-1520) and Leonardo (1452-1519).

After constructing a timeline (see Graph 1), students will learn more about these Italian artists and about a lot of other things as well. (graph omitted)

Axes and variables. A few words about making graphs may be in order here. First, students must remember to label the points on the graph. Bar and line graphs have reference lines called axes. These axes often intersect at a zero point or some appropriate base figure of the data. The independent variable (what is changed) is usually written along the horizontal s. The dependent variable (what is being measured) is usually written along the vertical axis.

Before making this particular timeline, students must determine the lower and upper limits (1386-1564) of the graph. Once this is done, students can determine how many years each square of the graph paper represents. In the graph shown below, each square represents 10 years. (graph omitted)

There are all sorts of questions you can ask while your students study the graph. How old was each artist when he died? When Donatello died, how old was Leonardo? Which of the artists were adults (meaning age 20 or older) at the same time.

Have students think about the ages of these Ninja Artists when they died. Raphael, who died at the age of 37, was probably the "norm" for the time. In the 14th and 15th centuries, it was rare that people lived as long as the other three artists. Today, however, everyone expects to live at least into their 70's. This can lead to a discussion of the changes in medicine and technology that have taken place.

People living longer influences many facets of society. Why should people retire at 65 when they may live another 25 years? With people living longer, is Social Security a concept that has outlived itself?

Suddenly, this process lesson in art history has evolved into a Science-Technology-Society (S-T-S) issue encompassing gerontology, economics, employment, medicine and ethics.

It's a small world. A graph of the world's population presents a dismal picture, no matter how you look at it. (graph omitted) It took from the beginning of time to 1650 for the world's population to reach half a billion. Two centuries later, in 1850, the population had doubled and reached its first billion. In 1930, the population was 2 billion; in 1974, it jumped to 4 billion.

The doubling time has decreased tremendously since 1850, and now there's a net increase (the number of births minus the number of deaths) of one billion people in about 11 years. It's predicted that there'll be 6 billion people in the world by 1998 and 8 billion by the year 2020.

All of this can be rendered visually in a two-variable line graph (see Graph 2). Here, the dependent variable--population--goes on the vertical axis, while the independent variable--time--is on the horizontal axis. (graph omitted) The dependent variable changes from zero to 8 billion. The independent variable changes from the year 1650 to 2050, a span of 400 years.

Here are a few points your students can ponder after they've finished constructing the line graph.

* How accurate is the data?

* How can everyone in the world be counted? * What are some of the problems that are encountered while taking a census of a classroom? a school building; a town or city? the United States? the world?

* List the effects of a population increase in a school or a city.

* What are some of the variables that make the population increase and decrease? (Note: Some of your students are sure to mention war as a leading cause of population decrease. Sounds reasonable, but it just isn't so. All of the Americans killed in wars, for example, are replaced in 100 days.)