Variables & Scientific Method

1. Variables & Scientific Method Unit 1 – Intro to Science

2. Variables Unit 1 – Intro to Science

3. Variables • There are 3 types of variables • Independent Variable • The thing that you change • Dependent Variable • The outcome, depend on the independent variable • Controls • Things you leave the same, a standard of comparison, not all experiments have controls.

4. Constants • Sometimes these are confused with CONTROLS. • Constants are things that remain consistent throughout the entire experiment. • Temperature, materials, location, etc…

5. Example 1- Independent Variable • Investigating how a weight affects the length of an elastic band. • Independent Variable • The weight applied • You decided which weights to use

6. Example 1- Dependent Variable • Investigating how a weight affects the length of an elastic band. • Dependent Variable • Length is the dependent variable. • You measure the resulting length of the elastic band

7. Example 2 – Independent Variable • The longer the amount of time spent studying causes an increase in test scores • Independent Variable • Time spent studying • You decide how long/much to study for a test.

8. Example 2 – Dependent Variable • The longer the amount of time spent studying causes an increase in test scores • Dependent Variable • Test scores • This should change based on how long you study

9. Additional Examples

10. Independent Variable The independent variable is always located on the X axis of a graph. It is usually the “X” in a table or equation. The independent variable stands alone (not dependent on anything) The independent variable is what happens first.

11. Dependent Variable The dependent variable is always located on the Y axis of a graph. It is usually the “Y” in a table or equation. The dependent variable DEPENDS on the independent variable. The dependent variable is what happens second.

12. Scientific Method Unit 1 – Intro to Science

13. Science • “Sci” means “to know” • We know things from facts that can be proven through data and evidence • We gather facts through the scientific method. • The Scientific Method • A pattern that scientist use to investigate or solve a specific problem.

14. Steps in the Scientific Method • Identify a problem • Research the problem • Develop a hypothesis • Design experiment (Independent and Dependent) • Test/Conduct the Experiment • Analyze the Results • Form Conclusions • Repeat / Publish

15. Example 1 • Identify a problem • Noticing that many salamanders near a pond have curved, not straight tails.

16. Example 1 • Research the Problem • Go to library and research reputable journals. • Research using internet but only trustworthy sources. • Prior knowledge or experience

17. Example 1 • Develop a Hypothesis • A hypothesis is a possible explanation for a set of observations or answer to scientific question, predicts an outcome • Should be written as • “I think _______ because______.”

18. Example 1 • Design an Experiment • Is a test made up of variables that can be tested or compared. There are 3 types of variables in an experiment.

19. Example 1 • Carry out experiment • Make observations during the experiment • Types of observations • Quantitative (Quantity) • Using numbers • Qualitative (Quality) • Descriptive • Using your 5 senses (touch, smell, etc.

20. Example 1 • Analyze Data • Charts • Graphs • Tables • Averages • Visual Ratings • Bar Graphs, Line Graphs normally used.

21. Example 1 • Form a conclusion • We summarize what the data (tables, charts and graphs) reveals. • Discuss any changes you may want to make in your experiment and why.