InterActions in Physical Science

To answer this question, you deliberately changed the pendulum length. Each pair of partners had a pendulum with a different length. To find out what happens when the pendulum length changes, you measured how much time it took for the pendulum to make 10 back and forth swings. Was the design of this experiment a fair test? That is, were all pendulums treated in the same way?

To figure out if the design of the pendulum experiment was a fair test, review the pendulum activity (Activity 2) and then answer these questions.

4.In the experiment, the length of the pendulum was changed and the time to make 10 back and forth swings was measured. Were any other variables deliberately changed?
5.What variables were kept the same in the pendulum activity?
6.Was the design of the pendulum experiment a fair test? State your reasons.

Participate in a class discussion of these questions.

Make Sense of Science Words

Consider the key question for this activity: “What makes the design of an experiment good or poor?” To understand how scientists might answer this question, you need to know the meaning of some terms:

variables	manipulated variable
relationship	hypothesis
fair test	responding variable

Science Words
variable: something
in an experiment that changes or can be changed

A variable is something about an object or event that can change or be different. For example, the length of someone’s hair can change over time. The color of someone’s eyes does not change over time, but one person may have green eyes and another person may have brown eyes. Hair length and eye color are variables. Variable comes from the verb “to vary,” which means to change.