1. I-N-D-E-P-E-N-D-E-N-T variables, dependent variables, and constants
Catalyst
What question is this data table answering?
What is one conclusion we can make from looking at this data table?
Write a hypothesis to answer this question: Why is hydro (water) power used so greatly?
Write in complete sentences!
Don’t talk during the Catalyst!

2. By the end of today, SWBAT…
Objectives
By the end of today, SWBAT…
Identify independent, dependent, and controlled variables in a scientific experiment

3. Experimentation
Key Point #1: A proper experiment always has an independent variable and dependent variable.
The purpose of an experiment is to test how changing ONE THING affects something else.
Bring em in. We discussed making observations, questions (kinda), making hypotheses, lets discuss how we test our guesses to questions.

4. Variables
Independent Variable: what causes the change we are measuring (acts independently)
Dependent variable: what gets changed (depends on other things)
Remember
Variables are always CATEGORIES of things: time, amount, frequency, size, type
Variables are NEVER specific things!!!
Ask your students, what was the thing I changed? What did I measure?

5. Demo
videos/dsc/externalApplications/ virtual_labs-es/Plants/index.html

6. Teacher Models
Scientists have discovered something shocking: if you eat a lot of candy, then you will gain fat. What is the independent variable?
Eat a lot of candy
Type of candy you eat
Amount of candy you eat
How much weight you gain

7. Teacher Models
Happy students learn more in school. So, Mr. LY believes that starting school later would increase test scores. What is the dependent variable?
Starting school later
Happy students
Time that school starts
Test scores

8. ActivExpression 1
Mr. LY believes that the more you study, the better grades you’ll earn. What is the independent variable?
Studying more
Amount of time you study
Grade earned
Type of test

9. ActivExpression 2
Shanel is always cold in class. She hypothesizes that if she wears many layers of clothing to school, then she will be warmer. What is the dependent variable?
Number of layers Shanel wears
How cold Shanel is
Temperature of the room
Shanel will be warmer

10. ActivExpression 3
Mr. LY’s students want to test how easily bought off he is. Students who give him an apple get a “C.” Students who give him candy get an “A.” What is the independent variable?
Type of food
Apples and candy
“A” on the report card
Report card

11. ActivExpression 4
Jenika hates running, but loves listening to music. She believes that if she listens to music while running, then she will run more often. What is the dependent variable?
She will run more often
Listens to music while running
Frequency that Jenika runs
What Jenika listens to

12. If you’re having trouble…
WRONG
RIGHT
4 minutes
26 mg of baking soda
Lifting weights every day
Medium t-shirts
Bullfrog
16 candles
Never gets sick
Time to get dressed
Amount of baking soda
Frequency of lifting weights
Size of t-shirts
Type of frog
Number of candles
Degree of health
Variables will (almost) always have one of these key words

13. Review
Mr. LY believes that the more you study, the better grades you’ll earn. What is the independent variable?
Studying more
Amount of time you study
Grade earned
Type of test
Walk students back through the previous four questions to review answers.

14. Review
Shanel is always cold in class. She hypothesizes that if she wears many layers of clothing to school, then she will be warmer. What is the dependent variable?
Number of layers Shanel wears
How cold Shanel is
Temperature of the room
Shanel will be warmer

15. Review
Mr. LY’s students want to test how easily bought off he is. Students who give him an apple get a “C.” Students who give him candy get an “A.” What is the independent variable?
Type of food
Apples and candy
“A” on the report card
Report card

16. Review
Jenika hates running, but loves listening to music. She believes that if she listens to music while running, then she will run more often. What is the dependent variable?
She will run more often
Listens to music while running
Frequency that Jenika runs
What Jenika listens to

17. Guided Practice Worksheet
8 minutes to complete
3 minutes to compare answers
KEEP THIS to help you with homework tonight

18. Constants
Key Point #2: Everything but the independent and dependent variable must be kept constant.
Constant: variable we keep the same
If many different things change at once, we don’t know what causes the change!

19. Example
Let’s say we want to design an experiment to determine what causes GSP to win fights.
Ask students to identify IV, DV

20. Number of fights that GSP wins
On this slide, we are making a cause-effect diagram.
Write out everything that could possibly affect whether GSP wins. Choose ONE to be the IV---everything else must be held constant! Or else you do not know what is causing the change. Note that “frequency that GSP wins” is a good DV because it is a category.

21. Answer in notes
Jay-Z hypothesizes that if he stops cussing, then he will sell fewer CDs because students like cussing.
What is the IV?
What is the DV?
What are the constants?
Remember, variables are
CATEGORIES.
Sometimes you will have to figure out variables after reading someone’s hypothesis.

22. If [Jay-Z] stops cussing, then he will sell fewer CDs because students like cussing.IV
Frequency that Jay-Z cusses
How often Jay-Z cusses
Amount of curse words in Jay-Z songs DV
Number of CDs Jay-Z sells
How many CDs Jay-Z sells
Constant
Amount of money CDs cost
Number of tracks on each CD
How good each CD is
Sometimes you will have to figure out variables after reading someone’s hypothesis.

23. Whiteboard Practice When Mr. LY says “GO!”
Send up one member of your group to get whiteboards and markers for everyone
Send up another member of your group to get napkins for everyone
Hurry! Remember, we want to stay under 3 minutes of transition time!

24. Practice
You want to know when in the year there are the most love bugs. Every night, you record how many love bugs you find outside.
Time of year (season/month)
IV =
DV =
Constant =
Amount of love bugs

25. Practice
Jenika needs to run a 6 minute mile to pass PE. She believes that if she runs every day, then she will be able to run faster.
IV =
DV =
Constant =
Frequency that Jenika runs
Mile time

26. Practice
Students of different genders were given the same puzzle to assemble. The puzzle assembly time was measured.
IV =
DV =
Constant =
Type of gender
Time to assemble puzzle

27. If there are more students, then there will be more school buses.
IV =
DV =
Constant =
Amount of students
Number of school buses

28. If the cost of beignets increases, then fewer will be sold.
What depends on what?
IV =
DV =
Constant =
Amount each beignet costs
Number of beignets sold
If the cost of beignets increases, then fewer will be sold.

29. If the Saints sign more free agents, then they will win more games.
IV = Number of free agents
DV = Number of games won
Constant =

30. Conclusion
Key Point #1: A proper experiment always has an independent variable and dependent variable.
Independent Variable: what causes the change we are measuring
Dependent variable: what gets changed
Constant: variable we keep the same
Ask your students, what was the thing I changed? What did I measure?

31. Exit Question
Let’s say you want to figure out if drinking milk actually makes you taller. So you drink a glass of milk every day, and record your height every day.
What is the independent variable?
What is the dependent variable?
What are at least two constants?
Write in complete sentences!
Don’t talk during the Exit Question!