1. Scientific Methodology

2. Science is a process of inquiry that includes repeatable observations and testable hypotheses

3. The scope of science is limited to the study of structures and processes that we can observe and measure, either directly or indirectly.

4. Verifiable observations and measurements are the data of discovery science.

6. Can Science Answer all Questions?

7. What is an example of a question that science cannot answer?

9. Observation
Question

10. Hypothesis
Tentative solution
Possible answer
Not an educated guess!

11. A good hypothesis: Reflects past experience Must be testable
Can be eliminated but not confirmed with absolute certainty.

12. Experimentation
Testing of the hypothesis

13. Controlled Experiment

14. Dependent Variable
The variable which will be measured, counted or observed.

15. Independent Variable
The experimental condition which is manipulated.

16. Although there are many factors which might affect the dependent variable – only one is chosen. Why?

17. Controlled Variables
Variables which must be kept constant so they do not affect the dependent variable.

18. Design of procedure:
Includes -

19. Level of Treatment The value set for the independent variable.
Based on previous research.

20. Replication
Repeating the procedure several times.

21. Control Treatment:
Portion of the experiment in which the independent variable is held to an established level or is omitted.

22. Control Experimental

23. Positive control groups are control groups where the conditions guarantee a positive result. Positive control groups are effective to show the experiment is functioning as planned.
Negative control groups are control groups where conditions produce a negative outcome. Negative control groups help identify outside influences which may be present that were not unaccounted for, such as contaminants.

24. If both the treatment group and the negative control produce the result, it can be inferred that another variable acted on the experiment and the data is discarded. If the positive control does not produce the result, there may be something wrong with the experiment procedure and the experiment is repeated.
If both controls behave correctly, the results of the experiment are concluded to be the effect of the desired variable.

25. Collection and analysis of data.
A first step usually involves constructing tables and graphs

26. Sample Data Table
Title: The Effect of the independent variable on the dependent variable
Column for independent variable
Column for dependent variable
Column for derived quantity
Label – with units if necessary
Label – with units if necessary – multiple trials included
Label – with units if necessary. Example = average of trials 1 4 2 6 3 7 9

28. The type of graph to use depends on the type of data collected.
Bar vs. Line Graphs - Which Should I Use?
The type of graph to use depends on the type of data collected.
Two kinds of data: Discrete and Continuous
Discrete data are categorical like days of the week, color, and brand of battery. Intervals between the data have no meaning.
USE A BAR GRAPH
Continuous data are associated with measurements
involving a standard scale. Measurements should be able to show a trend or relationship. Intervals between data have meaning.
USE A LINE GRAPH

30. We don't use graph titles in college lab reports--only figure legends
We don't use graph titles in college lab reports--only figure legends. For example: Figure 1. Effect of catalase concentration on reaction rate. Different volumes of yeast catalase were mixed with H2O2 and the amount of remaining substrate (H2O2) measured by titration.

31. If you are doing formal write-ups, every figure or table should have a paragraph-long caption, not just a title. The reasoning is that most readers of a journal article only read the abstract and look at the pictures. If the figures are mysterious, they never read the paper, so the figures and captions have to convey the main ideas of the paper. Even those who do read the full paper generally thumb through and look at the pictures first. The figures and captions should amount to a poster presentation of the whole paper.

32. Lines of best fit:

33. Lines of best fit:

36. The knowledge that any individual measurement you make in a lab will lack perfect precision often leads a researcher to choose to take multiple measurements at some independent variable level. Though no one of these measurements are likely to be more precise than any other, this group of values, it is hoped, will cluster about the true value you are trying to measure. This distribution of data values is often represented by showing a single data point, representing the mean value of the data, and error bars to represent the overall distribution of the data.

39. What is wrong?

41. Problems with the preceding figure:
Title below figure
First word only capitalized
Title incomplete
Y-axis – no label
No increment marks between numbers
No data points
Labeling of lines is confusing

42. Analysis may involve statistical methods
Interpreting data
Draw conclusions

43. Revise hypothesis?
Publication?
Peer review

44. Hypotheses that are supported by many researchers may gain the status of theory.
NOT the same meaning as in everyday conversation!

45. Theory is the highest level of proof in science.

46. Standards for your lab reports:

48. Science can be distinguished from other styles of inquiry by:
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

49. (1) a dependence on observations and measurements that others can verify, and
(2) the requirement that ideas (hypotheses and theories) are testable by observations and experiments that others can repeat.

50. Laws are observations for which there are no known exceptions.
Laws are explained by hypotheses (theories)

51. Types of research:
Quantitative
Descriptive / Observational / Correlational