1. CATALYST 1.) Pick up your HOMEWORK PACKET and graded quizzes in the graded work folders. 2.) Answer the following questions on the LEFT PAGE: What is an independent variable? What is a dependent variable?

2. Agenda Quick Reminders Quiz Tracker Variables Independent Dependent Practice Wrap Up General Science – Tues, 09.02.2008

3. Quick Reminders Bring science fair notebook tomorrow! HW Packet #3 Due Friday, 09.05.2008. Quiz #3 on Friday, 09.05.2008. General Science – Tues, 09.02.2008

4. QUIZ TRACKER General Science – Tues, 09.02.2008

5. Objectives SWBAT: Articulate what independent and dependent variables are. Write a statement which contains independent and dependent variables.

6. Variables 09.02.2008

7. Variable Definition “varius” (Latin) means “changing” “able” (Latin) is used to form words that describe (adjectives) and means “capable or worthy of” So when you combine the two roots of the word variable you get the meaning: Something that is capable of changing

8. Variables 09.02.2008 Origin-Varius (“changing”) + able (“capable of”) = variable (“capable of changing”)

9. Variable In a scientific experiment, a variable is any factor or trait or condition that can exist in differing amounts or types. EX: The effect of weather conditions on the amount of citrus fruit produced.

10. Why are variables important in scientific inquiry? Scientists use variables in their experiments to search for Relationships in nature.

11. Variables 09.02.2008 Origin Importance -Varius (“changing”) + able (“capable of”) = variable (“capable of changing”) - Helps find relationships in nature

12. Why are variables important in scientific inquiry? In other words, they design an experiment so that changes to one item cause something else to vary (change) in a predictable way.

13. Variables 09.02.2008 Origin Importance -Varius (“changing”) + able (“capable of”) = variable (“capable of changing”) -Helps find relationships in nature - Setup expmts. to change one item & see how affects other items

14. Types of Variables An experiment usually has three kinds of variables: independent, dependent, and controlled. Today we are only going to talk about independent and dependent variables.

15. Independent Variable An independent variable (IV) is a variable in the experiment that the experimenter changes or manipulates I ndependent variable is what I can change.

16. Variables 09.02.2008 Origin Importance Types -Varius (“changing”) + able (“capable of”) = variable (“capable of changing”) -Helps find relationships in nature - Setup expmts. to change one item & see how affects other items - Independent (IV) – experimenter changes (“Independent = I change”)

17. Independent Variable As the scientist changes the independent variable, he or she observes what happens.

18. Dependent Variable The dependent variable is what changes when the independent variable changes The dependent variable is what we measure

19. Variables 09.02.2008 Origin Importance Types -Varius (“changing”) + able (“capable of”) = variable (“capable of changing”) -Helps find relationships in nature - Setup expmts. to change one item & see how affects other items -Independent (IV) – experimenter changes (“Independent = I change”) - Dependent (DV) – what changes when IV changes; what we measure

20. Dependent Variable The scientist focuses his or her observations on the dependent variable to see how it responds to the change made to the independent variable. The new value of the dependent variable is caused by and depends on the value of the independent variable.

21. Practice Identifying Variables QUESTION 1 How much water flows through a faucet at different openings (closed, half open, fully open)? INDEPENDENT VARIABLE DEPENDENT VARIABLE

22. Variables 09.02.2008 Types Examples -Independent (IV) – experimenter changes (“Independent = I change”) -Dependent (DV) – what changes when IV changes; what we measure - Q1: How much water flows through a faucet at different openings?

23. Practice Identifying Variables QUESTION 1 How much water flows through a faucet at different openings (closed, half open, fully open)? INDEPENDENT VARIABLE Water faucet opening (closed, half open, fully open) DEPENDENT VARIABLE Amount of water flowing measured in liters per minute

24. Variables 09.02.2008 Types Examples -Independent (IV) – experimenter changes (“Independent = I change”) -Dependent (DV) – what changes when IV changes; what we measure - Q1: How much water flows through a faucet at different openings? IV1: Water Faucet Opening (Closed / Half Open / Fully Open) DV1: Amount of Water Flowing

25. Practice Identifying Variables QUESTION 2 Does heating a cup of water allow it to dissolve more sugar? INDEPENDENT VARIABLE DEPENDENT VARIABLE

26. Practice Identifying Variables QUESTION 2 Does heating a cup of water allow it to dissolve more sugar? INDEPENDENT VARIABLE Temperature of the water measured in degrees Celsius DEPENDENT VARIABLE Amount of sugar that dissolves completely measured in grams

27. Practice Identifying Variables QUESTION 3 (ON LEFT PAGE) Does an electric motor turn faster if you increase the voltage? INDEPENDENT VARIABLE DEPENDENT VARIABLE

28. Practice Identifying Variables QUESTION 3 (ON LEFT PAGE) Does an electric motor turn faster if you increase the voltage? INDEPENDENT VARIABLE Voltage of the electricity measured in volts DEPENDENT VARIABLE Speed of rotation

29. Variables OVERVIEW Independent Variables What I change Dependent Variables What is being measured

30. SUMMARY & PRACTICE Take 3 minutes to write your summary. When you are done, begin working on your HW Packet!