Activity 4

Evaluating Experiment Designs

Purpose

In the last activity, you learned about good and poor experiment designs. A good design involves a fair test of the experiment question. A poor design does not. Scientists have developed criteria (standards) for evaluating an experiment. The criteria are used to decide if the experiment is a fair test. The purpose of this activity is for you to practice using these criteria. Here is the key question for this activity.

What are the criteria for evaluating an experiment design for a fair test?

Record the key question on your record sheet.

Explore Your Ideas

Imagine that for a science project, you do the following experiment:

Experiment: If different Earth’s materials are heated by sunlight, is the final temperature the same or different for each? 

You decide to work with two of the Earth’s materials, dirt and water. You fill one bucket with dirt and half-fill an identical bucket with water. You place them so each bucket receives the same amount of sunlight. You place identical thermometers at the same depth and location in each bucket. You make sure each thermometer reads the same temperature at the beginning. Two hours later, you measure the temperature of each bucket. You compare the two temperatures. Is this experimental design good? Is the experiment a fair test?

   Analyze the Experiment

1. 1. What is the question the experiment is designed to answer?
2. 2. Identify the manipulated variable (the variable that was deliberately changed) and the responding variable (the variable that was measured).