Designing a Fair Test

Scene: Debate after the Race

Duration: Approximately 50 minutes

In this Science Scene, a dialogue to read aloud as a class, students are introduced to the idea of a fair test through a discussion about an unfair running contest. The characters discuss why it was unfair and uncover the problems that occur when the principles of a fair test are not included.

Most students have had some exposure to competitions and contests that try to determine the “best” at some skill. This unit's scene demonstrates a group of students struggling to understand what makes a contest fair.

LEARNING OBJECTIVE

Students will closely examine the details of the narrative and consider the necessary elements for a test (team tryouts) to be fair.

Students are introduced to the Focus Words, scientific language used throughout this unit.

Students practice using this important vocabulary and scientific terminology.

Teacher Tips

• Think ahead about how you will assign the three roles (Gregory, Angelina and Monique), perhaps in groups or by having volunteers read in front of the class. Note that students often willingly take on roles regardless of the gender of the characters.
• While it is possible for the students to read the PDF of the script online, we suggest printing the script for the students so they can hold it in their hands and mark it as they read. Consider scaffolding the lesson for English language learners: you could let them preview the script before the lesson or read the dialogue silently once and ask questions to a partner.
• Prior to the reading the script, explain to students that they will encounter new vocabulary terms and ideas that may not be familiar. Reassure them that this lack of familiarity is okay. The reading is meant to introduce the ideas, not explain them completely.
• Review the focus words of the week. The focus word chart linked on the unit overview page should be used as a resource for students to review definitions and sample sentences.
• This activity is intended only as an introduction to the concepts.
• When roles are assigned, it is recommended that the teacher read the part of the narrator.

Teacher Tune-up

• How are variables, objective measurement and multiple trials part of designing a fair test?

Paraphrase and discuss:

You may hear a younger brother or sister say “that’s not fair” when a parent allows an older child to attend an event late at night. This use of the word “fair” is subjective (not objective) and cannot be tested.

In science class, we use the word “fair” in a different way. To be fair, we measure and/or test something using a specific process in order to get as close to the truth as possible. For example, if we want to find out if water or alcohol evaporates faster, we would control variables such as the amount of liquid, the shape of the containers, and where they are placed in the sun.

Some teachers have several groups of students read at the same time. Other teachers select a few students to "perform" in front of the class.

While it is possible for the students to read the PDF of the script online, we suggest printing the script for the students so they can hold it in their hands and mark it as they read. Consider scaffolding the lesson for English language learners: you could let them preview the script before the lesson or read the dialogue silently once and ask questions to a partner. When roles are assigned, it is recommended that the teacher read the part of the narrator as it is there that the focus words are explained.

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The Script:

Setting: Gregory pushed the door hard as he walked out of school. It had not been a good day. There had been a contest to figure out who was the best runner in the school. He had been sure that he would win, but he had lost to Evan. His friends Angelina and Monique were waiting for him when he came out the door.

Angelina: Why are you so mad about losing? Get over it. You lost.

Gregory: That contest was not fair!

Angelina: What do you mean “not fair?” You ran a race and you lost.

Gregory: But that’s just it. I only got to run one race. I know I’m faster than Evan. He knows it too. If I had a chance to run again, I’m sure I’d beat him.

Monique was quiet. She had watched the race and was thinking about whether Gregory might have won if he had done multiple trials.

Monique: I don’t know if you would have won if you got to run more than once. Evan ran pretty fast.

Gregory: I also had to run right after lunch. Everyone knows you never run your fastest right after eating. Evan had lunch an hour earlier!

Monique: Okay, I guess I can see how lunch might change how fast you can run.

While Monique agreed that eating lunch was a variable in the race, Angelina didn’t think it was why Gregory lost.

Angelina: You can’t say lunch was the problem. Maybe some people run faster after lunch because they have more energy. You lost. Stop whining.

Gregory: Oh come on. Evan also had on brand new sneakers. I just have my old ones. How is that fair?

Angelina: You both ran the same distance. He crossed the finish line before you. Finish lines don’t lie.

Monique agreed that using the finish line was an objective way to figure out who was fastest, but she thought Angelina was being too tough on Gregory.

Monique: Gregory, you seem to think lots of things about this contest were unfair. What would you do differently?

Gregory: I just think the whole process is wrong. The way that they choose the BEST runner shouldn’t come from only one race. Things have to be more fair. There need to be some more rules.

Angelina: Like what? How are you going to make the contest better?

Gregory thought for a while. There had to be a way of controlling variables in the contest to make sure it actually tested who was the best runner in the school.

Gregory: Everyone should have to run in the morning. No one should get to wear brand new clothes or special shoes for running. I think things like that would make it more fair.

Angelina: I guess you have a point. Saying something is the best doesn’t make a lot of sense unless the test is fair. Maybe next year you can see if the teachers will change some of the rules.