Setting: Erin scanned the crowded cafeteria and saw her friends Clara and Jose sitting at a table near the window. She quickly joined them, claiming the last empty seat at the table.
Clara: Hey Erin! Didn’t you try out for the gymnastics team yesterday? How did it go?
Erin: It was really awful. I had to do all of these jumps and flips, which was fine. But sometimes the coach wanted me to land on one foot. I was not happy. I fell every time.
Clara: I’m sorry. That sounds really bad.
Erin: I just have no balance. I guess I’ll never be on the team.
Jose: Don’t think like that. You know what? I think I can help you improve your balance!
Jose: Really. So, last year my cousin got this special bracelet for Christmas that is supposed to help with balance. It had magnets or something in it. She said it helped her so much that she made the dance team on her first try.
Clara: Jose, do you actually believe that was why she made the team? How can a bracelet make you a great dancer?
Erin: I don’t know. But, what if it really works?
Clara: I bet it’s just another one of those silly things that people tell you on TV so they can take your money. Last year my dad bought some machine that was supposed to make his stomach flat. He still has a belly and the device is now in the closet.
Erin: How can a company say that? How can they make a claim like that without proof? I’m sure the company selling the bracelet tested it to see if it really did help improve balance.
Jose: Well, I’ve got my evidence. It worked for my cousin, and that’s enough for me.
Clara: I’m not so sure that the company conducted the kind of experiments that would prove the bracelet helps with balance. There are so many variables that can affect a person’s balance. For example, I had an ear infection two weeks ago. One morning I almost fell getting out of bed because I was so dizzy. My mom said that your inner ear plays a role in balance, which seems strange to me.
Erin: Well, why don’t we conduct our own test? Let’s buy a bracelet and see if it works under different conditions.
Erin believed that the claim that the bracelet could improve balance was definitely testable, and that conducting the test would show if the bracelet worked. Clara was still skeptical, and Jose realized they might have a problem.
Jose: We could do an initial test with one bracelet, but I think in the end we’d have to test more than one of them and my cousin said they are expensive.
Clara: I think we will be better off if we investigate how other variables might affect Erin’s balance in the tryouts. One variable could be the food you eat. It could be that your balance was off because you were feeling weak. Maybe all you needed was to eat breakfast. Another variable could be the amount of sleep you get. Maybe you didn’t get enough sleep the night before the tryouts.
Erin: You really think there are that many variables that can affect balance? Variables–such a great word!
Clara: Of course. All we need to do is figure out, I mean determine, what might help you improve your balance so you make the gymnastics team.
Jose: Let’s all investigate. And Erin, just remember, we can always buy you a bracelet if nothing else works!
The friends decided that they would investigate variables that might improve a person’s balance. They made a plan to meet the next day.