STEP 2 Analyze the following corn experiment.

Imagine that you are a botanist, a scientist who studies plants. You want to breed a new kind of corn plant to help countries that do not have enough land for growing food. You have bred four different types of new corn seeds. You are ready to do an experiment to find out which type of corn seed will grow best in crowded conditions.

Experiment 3: If the type of corn seed is changed, then what happens to its health and growth rate in crowded conditions?

You have four identical pots. You plant 20 corn seeds in each pot. Each pot has a different type of corn seed.

All of the pots have the same amount of soil, and all the seeds are planted at a depth of 4.0 cm. Pot #1 has soil from your back yard. Pot #2 has clay soil. Pot #3 has sandy soil. Pot #4 has topsoil with added fertilizer. You water each pot every day with 500 mL of water.

After 3 weeks, all of the corn seeds in Pot #4 have sprouted and have green, healthy leaves. Many of the seeds in the other pots did not sprout, and those that did were not as tall and healthy. 

You conclude that the type of corn seeds in Pot #4 is the best. You decide to produce a lot of these seeds to sell to people who have a limited amount of land for growing crops. 

Was your experiment a fair test?

1. Record your answers to the questions about the corn experiment on the record sheet.

Participate in a class discussion to review your answers.

My Ideas

The key question for this activity is:

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

1. Based on what you learned in this activity, write your answer to the key question.

Your teacher will go over with you How To Analyze an Experiment Design and Determine if the Experiment is a Fair Test. Compare your ideas to those on the form. You can use this form in the future when you need to analyze an experiment to decide whether it is or is not a fair test.