1. Scientific Laws & Theories
Scientific Knowledge
Scientific Laws & Theories

2. Theory
if something is said to be “just a theory,” it usually means that it is a mere guess and unproven.
In scientific terms:
Scientific theory implies that something
has been proven and is generally accepted
as being true.

3. Theory A THEORY: a well-supported EXPLANATION of a set of
related observations or events based upon
proven hypotheses and verified multiple times
by different researchers. One scientist cannot
create a theory; he can only create a
hypothesis.
(Example: Theory of Evolution)

4. Theory THEORIES MUST: Be supported by data
Be verified by other experiments (LOTS OF TESTING)
Subject to review by peers (other scientists)
May be modified or expanded if additional data
is found

5. LAWS A DESCRIPTION of a specific relationship under given conditions
in the natural world.
(Why do objects fall toward the earth?)

6. LAWS DESCRIBES the way the world works.
It is generally accepted to be true based
upon the fact that they have always been
observed to be true.
(Example: Law of Gravity)

9. There Are Different Forms of the Scientific Method!
Science
defined as a methodical approach
to the acquisition of knowledge.
There Are Different Forms
of the Scientific Method!

10. use experimental forms of the may use a form of the scientific method.
Physical Sciences: (physics and chemistry)
use experimental forms of the
"scientific method."
- do experiments to gather numerical data from which
relationships are derived, and conclusions are made.
Descriptive sciences: (zoology and anthropology)
may use a form of the scientific method.
- involves gathering of information by
visual observation or interviewing.

11. considered data, and how data is
Common among all sciences
is the making of hypothesis:
- to explain observations
- gathering of data, and based on this data
- drawing of conclusions that confirm or
deny the original hypothesis.
The difference is in what is
considered data, and how data is
gathered and processed.

12. Data for a Physical scientist are numbers numbers are often plotted on graphs Graphs can be used to derive equations that can be used for making predictions. Data for an Anthropologist could be a recorded interview interviews can be compared to other related information.

13. Steps in the Scientific Method
Observation
Hypothesis
Experiment
Data Collection
Conclusion
Retest 13

14. Observations Gathered through your senses
A scientist notices something in their natural world

15. Observations
An example of an observation might be noticing that many salamanders near a pond have curved, not straight, tails

16. Hypothesis A suggested solution to the problem. Must be testable
Written as an If…Then… statements
Predicts an outcome

17. Hypothesis
An example of a hypothesis might be that the salamanders have curved tails due to a pollutant in the moist soil where they live.

18. A procedure to test the hypothesis.
Experiment
A procedure to test the hypothesis.

19. Variable – factor in the experiment that is being tested

20. A good or “valid” experiment will only have ONE Testable variable!

21. Controls and Variables Control, Independent & Dependent

22. Scientific Experiments Follow Rules
An experimenter changes one factor and observes or measures what happens.

23. The Control Variable
The experimenter makes a special effort to keep other factors constant so that they will not affect the outcome.
Those factors are called constant variables.

24. What is the Purpose of a Control?
Controls are NOT being tested
Controls are used for COMPARISON

25. Other Variables
The factor that is changed is known as the Tested (Independent) variable.
The factor that is measured or observed is called the Outcome (Dependent) variable.

26. Example of Controls & Variables
For example, suppose you want to figure out the fastest route to walk home from school.
You will try several different routes and time how long it takes you to get home by each one.
Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.

27. What are the Variables in Your Experiment?
Varying the route is the independent variable
The time it takes is the dependent variable
Keeping the same walker throughout makes the walker a control variable.

28. One more thing… it is best to make several trials with each independent variable.

29. Valid Experiments what constitutes a valid experiment?

30. To be a Valid Experiment:
Two groups are required --- the control & experimental
There should be only one variable

31. Data Results of the experiment
May be quantitative (numbers) or qualitative

32. Data
Must be organized
Can be organized into charts, tables, or graphs

33. Displaying Data Tables, charts and graphs are convenient ways to
clearly show your data.
Be sure to consider how to best show your results with appropriate graph forms.
Be sure to give your charts and graphs an
appropriate title that explains what the data measures.
On line and bar graphs, the x and y axis must be appropriately labeled with correct unit of measure
(in metrics where applicable).
Displaying Data

34. Bar Graph relationships between groups.
A bar graph is used to show
relationships between groups.
The two items being compared do not
need to affect each other.
It's a fast way to show big differences.

35. A typical chart or table for this graph might look like this:
Notice how easy it is to see what was done in the experiment below with bean plant growth and different brands of fertilizer.
A typical chart or table for this graph might look like this:

36. Line Graph A line graph is used to show continuing dependent variable.
data; how one thing is affected by another.
It's clear to see how things are going by the
rises and falls a line graph shows.
This kind of graph is needed to show the
effect of an independent variable on a
dependent variable.

37. A typical chart or table for this graph might look like this:
In the sample below, the pulse rate of a person is shown to change over time. As time continues, the pulse rate changes.
A typical chart or table for this graph might look like this:

38. Pie Chart A circle graph is used to show how a part
of something relates to the whole.
This kind of graph is needed to show
percentages effectively

39. A typical chart or table for this graph might look like this:
In the sample below, the preference of Ice Cream flavors determined by a survey conducted of the people of Twin Groves.
A typical chart or table for this graph might look like this:

40. Conclusion
The answer to the hypothesis is based on the data obtained from the experiment

41. Conclusion
Should be written WITHOUT BIAS (the hypothesis may be WRONG so the experimenter must be OBJECTIVE and not try to make the experimental results come out the way they want them to); ETHICAL
Should state whether the hypothesis WAS or WAS NOT supported
Experiment only VALID (correct) if scientist is honest & unbiased

42. verify the results, experiments must be retested.
In order to
verify the results, experiments must be retested.

43. Replication vs. Repetition

44. Replication vs. Repetition
What is repetition?
conducting multiple trials of measurements or observations in a scientific investigation. YOU!!!!!

45. Replication vs. Repetition
What is replication?
the reproduction of a scientific investigation by another person or group to ensure the accuracy of an experiment. OTHERS!!!!

46. Replication vs. Repetition
Why should experiments be replicable?
All scientific investigations and experiments should be replicable (able to be replicated by
other scientists) to ensure the accuracy of the investigation/experiment and the results of the investigation/experiment.
Be able to compare methods (procedures) and
results obtained in a scientific investigation.

47. Solving a Problem 1) Identify a Problem
2) State Observations about the problem
3) Form a Hypothesis about the problem (if…then…)
4) Design an Experiment to test the hypothesis
5) Collect Data
6) Form a Conclusion
7) Retest

48. Scientific Method Reminders:
1. All measuring is to be done accurately and consistently
using metrics where applicable.
2. Keep a detailed daily record or log book for
measurements, changes and problems.
3. Take photographs, make diagrams or drawings of various
phases of your experiment.
4. Observations and measurements should be organized in
tables or charts that are clearly labeled.
5. Results should be graphed using one of the three
methods described above.
6. Don't become discouraged; work diligently and repeat an
experiment, if necessary.