1. W HAT IS A CONTROLLED VARIABLE ?

2. C ONTROLLED V ARIABLES Variables “Things that change”, they “vary” A controlled variable is something that we can “keep consistent” in an experiment to make our lab results/data as consistent as possible. Helps to reduce error in your results

3. E XAMPLES The Coke experiment: We can control the time of day we are tested, when the person is tested, how much coke/water we drink, what they eat, how much sleep each person gets, etc Any other controls?

4. P EA P LANT E XAMPLE Growing beans A student for a science fair competition decides to see how different color light affects the growing of plants. She tested pea plants and allowed them to grow. She taped different color cellophane to the planter. Her control group was pea plants grown in natural light. What is the IV and the DV? What are the different controlled variables? Ok, amount of water we give each plant, type of soil and plant, amount of sunlight, thickness of cellophane, type of planter, Time of the year, any others?

5. M ORE EXAMPLES Look at your IV vs. DV worksheet. We will be identifying the variables that must stay the same!!