1. A student conducts an experiment to determine the relative strength of boys versus girls. She has six 8 th grade students participate (3 girls and 3 boys). She conducts three trials. In each trial she has each student, one at a time, lift a weight above their head (s) as many times as they can. 1 st trial: The weight is 5 pounds 2 nd trial: The weight is 10 pounds 3 rd trial: The weight is 15 pounds Question: (1) What is the independent variable in this experiment? (2) What other factor(s) changed during this experiment? Bell Work SPI 0807.Inq.1 (Variables and Controls) Aug 19, 2013 0 Press the Right Arrow Button to Advance through the Presentation! Independent variable was the amount of weight Other changed factors include the number of repetitions, how much each student strained, how much sweat they produced, how heavy was their breathing, etc. These other changed factors are called dependent variables

2. Today’s Plan 1) Discuss objective(s), bell work, and birthdays. 2) View my website, discuss plan for this week 3) Collect duct tape 4) Give out textbooks 5) Watch PP presentations about dependent variables 6) (Time Permitting) quick review activity Copy this into your agenda! Get school supplies! Silly Thought Why do stores that are open 24 hours a day/7 days a week have locks on their doors? 0.5 SPI 0807.Inq.1 (Variables and Controls)

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

4. 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… Notes SPI 0807.Inq.1 (Variables and Controls) 2 2 Types of Variables Independent & Dependent

5. Notes SPI 0807.Inq.1 (Variables and Controls) 3 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… 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

6. The independent variable is… Notes SPI 0807.Inq.1 (Variables and Controls) 4 The dependent variable is the student’s rating 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. Example 01 the type of soft drink So what is the dependent variable? HINT: What is a factor that changed without you doing it?