1. Press the Right Arrow Button to Advance through the Presentation! SPI 0807.Inq.1 (Variables and Controls)  Notes • Dependent Variables in Experiments • Used with the scientific method Scientific Method (In List Format) Step 1: Ask A Question Step 2: Form A Hypothesis Step 3: Test The Hypothesis Step 4: Analyze The Results Step 5: Draw Conclusions Step 6: Communicate Results Step 7: Make Observations • Use dependentvariables when you test your hypothesis by doing experiments 1

2. Press the Right Arrow Button to Advance through the Presentation! SPI 0807.Inq.1 (Variables and Controls) Notes  2 Types of Variables Independent & Dependent • In an experiment… • …you should only test for ONE key thing at a time • When you repeat the experiment… • …only change this ONE key thing • This one thing is called… • ANYTHING ELSE THAT CHANGES IS CALLED… An Independent Variable A Dependent Variable 2

3. Press the Right Arrow Button to Advance through the Presentation! SPI 0807.Inq.1 (Variables and Controls) Notes  • So What Is A Dependent Variable? • Other factors that change because of the independent variable • These are the things that YOU DO NOT CHANGE…they change on their own • In other words, anything that changes on its own will be a… Dependent Variable • Imagine you are doing an experiment to determine which brand • of gum will have flavor that lasts the longest. • The one thing you will change each time is the brand of gum • So the independent variable is the brand of gum • How long the flavor lasts will change on its own • So the dependent variable is how long the flavor lasts 3

4. Press the Right Arrow Button to Advance through the Presentation! SPI 0807.Inq.1 (Variables and Controls) Notes  Example 01 You decide to do an experiment to determine the reason certain soft drinks are more popular that other soft drinks. You suspect that the popularity of the drinks is connected with the amount of sugar found in them. You decide to use Coke, Pepsi, and Dr. Pepper in this experiment. You first determine how much sugar each drink contains. Then you get 6 students to do a blind taste test with all 3 drinks. They rate each drink on a scale of 1 to 10. The independent variable is… the type of soft drink So what is the dependent variable? HINT: What is a factor that changed without you doing it? The dependent variable is the student’s rating 4

5. Press the Right Arrow Button to Advance through the Presentation! SPI 0807.Inq.1 (Variables and Controls) Notes  Example 02: • A scientist is conducting an experiment to test how • sunlight affects plant growth. • She places one corn plant 1 meter away from a sunlamp. • She places one corn plant 2 meters away from a sunlamp. • She places one corn plant 3 meters away from a sunlamp. The independent variable is… the amount of sunlight So what is the dependent variable? HINT: What is a factor that changed without you doing it? The dependent variable is the plant growth 5

6. Press the Right Arrow Button to Advance through the Presentation! SPI 0807.Inq.1 (Variables and Controls) Notes  Example 03: A student conducts an experiment with ten 8th grade students (5 boys and 5 girls). He uses 3 similar types of sour candy (Sour Skittles, Sour Patch Kids, and Warheads) in a series of 4 trials. He gives 1 piece of candy to each student and records their facial expressions as they eat it. The independent variable is… the type of sour candy So what is the dependent variable? HINT: What is a factor that changed without you doing it? The dependent variable is the student’s facial reactions 6

7. Press the Right Arrow Button to Advance through the Presentation! SPI 0807.Inq.1 (Variables and Controls) Notes  Example 04: A student conducts an experiment to determine which type of glue works best for attaching two pieces of regular writing paper together. He uses 3 types of Elmer’s glue in a series of experiments (1) Liquid-washable, (2) Glue Stick-washable, (3) Glue Stick-nonwashable) He places the same amount of glue (2g) on each sheet of paper. The independent variable is… the type of glue So what is the dependent variable? HINT: What is a factor that changed without you doing it? The dependent variable is how strongly the sheets of paper stick together 7

8. Press the Right Arrow Button to Advance through the Presentation! SPI 0807.Inq.1 (Variables and Controls) Notes  Example 05: A student conducts an experiment to determine which ink color in ballpoint pens will last the longest before running out. She uses 3 ink colors in 3 ballpoint pens in a series of experiments. (1) Black ink pen, (2) Blue ink pen, (3) Red ink pen) She copies text from his science book. She copies the same text over and over. She writes at the same speed. The room temperature remains the same. She writes on the same kind of paper. The independent variable is… the ink color So what is the dependent variable? HINT: What is a factor that changed without you doing it? The dependent variable is how long ink lasted 8