The Scientific Method

1. The Scientific Method Virginia Standard of Learning 6.1

2. SOL 6.1 The student will plan and conduct investigations in which: • observations of living organisms are recorded in the lab and in the field; • hypotheses are formulated based on direct observations and information from scientific literature; • variables are defined and investigations are designed to test hypotheses; • graphing and arithmetic calculations are used as tools in data analysis; • conclusions are formed based on recorded quantitative and qualitative data; • sources of error inherent in experimental design are identified and discussed;

3. SOL 6.1 The student will plan and conduct investigations in which: • validity of data is determined; • chemicals and equipment are used in a safe manner; • appropriate technology including computers, graphing calculators, and probeware, is used for gathering and analyzing data and communicating results; • research utilizes scientific literature; • differentiation is made between a scientific hypothesis and theory; • alternative scientific explanations and models are recognized and analyzed; and • a scientific viewpoint is constructed and defended (the nature of science).

4. The Scientific Method • An organized way to solve a problem through experimentation & observation.

5. 6 Steps of the Scientific Method • State the problem. • Collect information • Form a hypothesis • Design experiment • Collect & analyze data • Draw Conclusions & communicate results

6. 1. State the Problem • Form a question about a specific event or reaction EX: Mouthwash kills bacteria. Which brand works best?

7. 2. CollectInformation • Research the problem EX: Read the labels of 3 common brands of mouthwash and see which has the most antiseptic (germ-killing) ingredients.

8. 3. Form a hypothesis • Make an educated guess based on your research. A hypothesis can be recognized by an “if, then” statement. EX: If Listerine has more antiseptic ingredients than Scope or Wal-Mart brand, then it will kill more bacteria.

9. 4. Design an Experiment • Devise a way to test your hypothesis. Create a CONTROLLED experiment.

10. A controlled experiment MUST have 2 groups. CONTROL GROUP: all conditions remain the same (to compare) EXPERIMENTAL GROUP: only the condition that you are testing for is changed ONLY 1 condition is changed!

11. Establish the variables for your experiment. INDEPENDENT VARIABLE: variable that I, the experimentor, change manipulated (X axis for graphing) DEPENDENT VARIABLE: it responds to the manipulation of the independent variable; it is measured. (Y axis for graphing)

12. Mouthwash Experiment Control Group -no mouthwash Petri dish Bacteria grown from swab Listerine Experimental Groups Scope Wal-Mart brand

13. Mouthwash Experiment INDEPENDENT VARIABLE: Type of Mouthwash DEPENDENT VARIABLE: Amount of bacteria killed

14. 5. Collect & Analyze Data • Run the experiment & document the data

15. 2 Types of Data QUANTITATIVE: data involves NUMBERS & deals with specific quantities, usually in the form of a graph or chart QUALITATIVE: descriptive data involves words; describes how something looks, smells, sounds, or feels; deals with qualities

16. 6. Draw Conclusions • Determine from the data collected if the hypothesis was correct or incorrect EX: Listerine did kill more bacteria than the other brands because it had more antiseptic ingredients.

17. QUALITATIVE EX: The control group and the Wal-Mart brand have a strong smell; the Listerine & Scope don’t smell as bad. QUANITATIVE EX: Area of Inhibition for Mouthwash Brands

18. Progression of Ideas in Science • Hypothesis- a possible explanation to a question based on information the scientist has already gathered - If experiments show a hypothesis to be correct, other scientists may accept it as support for a scientific theory. EX: Plants obtain their energy from the sun.

19. Progression of Ideas in Science • Scientific Theory- a general statement of why things work based on hypotheses that have been tested many times • Scientific Law- a statement of what happens in a certain event based on verified observations & experiments

20. Progression of Ideas in Science - Theories are used to explain & predict the outcome of other experiments - Theories must be tested - Sometimes they are wrong & must be modified or discarded EX: The Earth is flat.

21. Progression of Ideas in Science - Explains what happens & not why - Summaries of the results of many, many experiments & observations - When results of a series of experiments are the same each time they no longer need to be tested EX: Newton’s Law of Gravity

22. Progression of Ideas in Science • Which one is most likely to be wrong- hypothesis, theory, or law? 1. 2. 3. Hypothesis Theory Law

23. Scientific Method Vocabulary • Observation-observing with the senses (touch, taste, smell, feel, see, etc.) • Inference-a quick conclusion that attempts to explain an observation • Prediction- to forecast; to guess the outcome of a situation beforehand • Analysis-to separate or break apart into smaller sections for study

24. Scientific Method Vocabulary • Conclusion- to close or bring to an end; to accept or reject a hypothesis in an experiment • Data-recorded observations or measurements • Hypothesis-educated guess that can be tested by further investigation

25. Scientific Method Vocabulary • Theory-explanation of a large body of information, experimental and inferential, and serves as an overarching framework for numerous concepts. It is subject to change as new evidence becomes available. • Law- a basic scientific theory that is no longer tested & is generally accepted as true (Newton’s Law of Gravity)

26. Scientific Method Vocabulary • Controlled Experiment- an experiment in which all variables except the ONE being tested are identical in order to make the experiment fair & the results reliable • Variable- any factor in an experiment that could affect the results & is therefore tested separately

27. Scientific Method Vocabulary • Controlled Variable- a variable that is not changed (for comparison) • Independent Variable –variable that I, the experimentor purposely change (manipulated variable) • Dependent Variable-variable that ismeasured & responds to the independent variable (responding variable)

28. Scientific Method Vocabulary • Quantitative Data- data that involves numbers or measurement usually in the form of a chart or graph • Qualitative Data- descriptive data involving words (does NOT involve numbers or measurement)