How Fast Do Ants Go?
by Howard Waterman
Type of Activity:
- Introductory Lesson/activity
- An Inquiry Lab
Abstract: This activity is designed so students can make discoveries about some important aspects of biology as a science. Through discovery students learn basic science precepts such as:
- Communication specificity
- Designing procedures to test theories
- Projecting outcomes
- Understanding controls and variables
- The need for standardized units in science
- The need for repetition in procedures - before making final decisions.
Assigned to measure the speed of an ant, students design the procedures and then collect and analyze data to solve the assigned problem "How fast do ants go?" (any available insect can be substituted.) No other information is provided except: 1) the procedure is written with as much technical detail as possible, 2) no harm befalls the ants, and 3) the procedure must be "do-able" (no Martian Ant Rays). From this assignment, students learn a great deal regarding science, mathematics, and the technical problems associated with building and using equipment to collect what appears to be very simple data.
The proposals students write are read only for specificity of technical presentation, not likelihood of success. Vague or abstract proposals are returned for clarification. Examples are read anonymously to illustrate good technical writing and demonstrate how vague writing can be improved - point out that placing an insect under the microscope and under the lens of the microscope are very different places.
Students construct whatever device they proposed. Construction devices are as varied as the imaginations of the students, ranging from sugar coated soda straws, concentric circles, to stretched strings and shoebox race tracks. Students bring ants, and help each other collect data. Soon they discover they cannot control the ants, start and stop watches, and record data all at the same time. Cooperating teams begin to form almost magically. Each student collects data according to their individual plan. Results are posted on the overhead and all students copy the data.
Many students experience difficulty calculating rate because their only experience with rate is from automobiles. They may feel compelled to do conversions to miles per hour. The mathematics of reporting is interesting and many students learn rate by trying to report their ant's speed. The units reported are bizarre. No attempt is made to correct their errors, but only to help implement their technical and mathematical plan.
When completed, the diverse data is copied by each student, much of it in strange and bizarre units. The "home study" assignment is to compute the average speed for all ants. The purpose of the assignment is not to actually calculate the average, but to have students realize the futility of the task. They are admonished to spend no longer than fifteen minutes in the attempt and will get full credit for turning in any work they did in the attempt provided they write a paragraph explaining what the problems were that made it impossible to complete the task in the allotted time.
Students report findings the next day and it is quickly revealed as an impossible task. The notion of uniform reporting and standard units comes up when they discuss their paragraphs and a decision is made in the future to standardize units. Metric units are agreed to because of their wide spread use and the need for conversions is eliminated. Students learn quickly why science, math and technology require standards of reporting and collecting data.
One student's reported ant speed is selected at random and with appropriate fanfare is announced as the correct speed for ants. This always elicits cries of "foul" since no one ant can be representative of all ants. Students quickly begin defending their ants and bring up a list of reasons why no one ant can be declared the winner. These are carefully listed on the board and given careful consideration. The term "variables" is applied to the list and students begin to recognize that many factors influence the quality of their data - everything from the health and age of the ant to the mathematical ability of other student researchers. Variables are identified as "internal" and "external".
The technical merits of each procedure are analyzed and the best technical procedure given due recognition. Procedures for neutralizing internal and external variables are discussed - averaging out variables by repetitive trials usually wins the argument. Students begin to appreciate why technical developments go through such rigorous testing and why it takes so much time to develop a device or procedure to accomplish precise repetitive tasks.
Allowing students to work through the frustrations of solving problems provides the incentive for them to accept the need for uniform procedures in testing, collecting data, and reporting data. Students recognize the need for precision in writing, accuracy in measurement, conformity to standards even though they often need considerable work at developing the skills. Once they see the value of the skill, they are more receptive to becoming willing proactive recipients.