Using Common Organisms
A few years ago I realized my students had little opportunity to do "real" science if they carried out routine labs with predetermined results or memorized and repeated isolated facts and terms. At that time I had not encouraged individual observations and follow-up experimentation. Then I began to develop my own labs working with common organisms encountered in daily life. After many years of testing and modification through classroom use, these labs have been compiled into two manuals, Learning Under The Sun and Learning For All Seasons.
The labs are based on a process of observation and inquiry that progresses into experiments and/or research using natural materials. Experiments often stimulate more questions, requiring further student observation and experimentation. In follow-up experiments, students learn to formulate and write hypotheses and procedures, list controls and variables, present the results in graphic or chart form, and draw conclusions.
Along with using common organisms in individual labs during class time, I assign other labs weekly as homework to illustrate science concepts, develop skills in observation, data gathering, recording results, and identifying variables. Some examples of weekly experiments include measuring the amount of lettuce consumed by a land snail in a 24-hour period (as a study of metabolism), or studying the effect of garlic on the growth rate of grass seeds (allelopathy).
Teaching science concepts using common organisms is not only good science, it is economical science. The materials needed to carry out the procedures are easily obtained from the local environment or are relatively inexpensive from supply houses. Sample lessons for using three common organisms follow.
Ants
In one lab students study ants in their natural schoolyard setting or bring them into the classroom. Working in teams of 2 or 3, students write 5 to 10 observations about ants. Youngsters often are amazed at the number of discoveries made when they closely watch this creature they have seen many times before, and they enjoy the excitement of learning something new about the familiar. Their observations of the ants and the ant hill give rise to questions such as how often do ants go in and out of the entrance to the hole? How far do ants venture from the hill to find food? Do ants act differently in full sun than they do in shade?
There are always more questions than answers,
and the inquiry process is the essence of science. Students often carry
out simple activities dealing with the behavior of an organism long before
they conduct more formalized experiments following the scientific method.
