On each of the following slides there is a story about a scientific experiment. Read the story and I will ask you to identify a variable in the experiment. you will write your answer on the whiteboard and hold it up when I ask you to.

Little baby Kelly does not sleep through the night. This is a problem because her mom kelly is not getting enough sleep. Jill designs an experiment that will test whether playing soft music in her room will reduce the amount of times she wakes during the night. Jill puts Kelly to bed each night at the same time for two weeks. For the first week, Jill does not play any music while Kelly sleeps. For the second week, Jill plays very soft classical music while Kelly sleeps. Jill counts the number of times Kelly wakes up each night.

Little Harry will not stop putting his hands in his mouth. This is a problem because his hands are covered with bacteria that can make him sick. Harry’s dad James is curious to see if putting lotion on his hands every morning will work to decrease the number of times he puts his hands in his mouth. For the first week, James does not put lotion on Harry’s hands and watches him for 2 hours each day. He counts how many times Harry puts his hands in his mouth each day. Then for the second week, James put lotion on Harry’s hands each morning and watches to see how many times he puts his hands in his mouth during the 2 hours.

Jeff wants to improve the number of goals he makes during his soccer season. Jeff usually plays soccer in sneakers. He decides to test if wearing cleats instead of sneakers will increase the number of goals he makes. Jeff plays 10 games this season. For 5 games he wears sneakers and for 5 games he wears cleats. For each game he records the number of goals he makes.

As a teacher I want to find a way to help my students score higher on tests. I develop a plan to stay after school twice a week instead of once a week to see whether that will raise the average test grade. Half of my students can only come once a week for extra help and the other half can come twice a week. After a month I give them the same test and find the average test grade for each group.