1. What is science? And scientific method

2. What is science?
Organized inquiry into the natural world and its phenomena.
GOAL of science….develop a deeper understanding of the natural universe without human bias.
Science is not exact or perfect. From time to time, scientific explanations may change as new data is presented. The process of testing and fine-tuning theories never ends as scientists try to gain new insights into old problems. Scientists use the scientific method to test these explanations.

3. Scientific Method: Meme Version

4. Steps in the Scientific Method
Observation
Hypothesis
Experiment
Results
Conclusion
(Retest)

5. 1. OBSERVATION – Make observations to gather information and form a question.

6. 1. Observations Gathered through your senses
A scientist notices something in their natural world
An example of an observation might be noticing that many salamanders near a pond have curved, not straight, tails

7. 2. Hypothesis and 3. Experiment
2. HYPOTHESIS – A hypothesis is a possible explanation or prediction that must be TESTABLE!!
3. EXPERIMENT– Test the hypothesis by conducting an experiment.
If unable to test using an experimental design then the statement remains a hypothesis. Hypotheses can be proven wrong, but can never be confirmed with absolute certainty.

8. Redi’s Experiment on Spontaneous Generation
OBSERVATIONS/PROBLEM: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
HYPOTHESIS: If meat is covered, then no maggots will appear.
CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation did not occur.

9. There are RULES in an experiment
Experiments need a control group to use as a standard for comparison.
Scientist must contrast an “experimental group” with a “control group”. The two groups are EXACTLY alike except for the ONE variable being tested.
Only test ONE variable during an experiment, so you know what caused the change!
Experiments contain variables which are factors in the experimental design.

10. 3 Types of Variables
Constants are variables that remain the same in each group. They do not change.
Independent Variable:   (IV) is the factor that changes or is being tested in the experiment
Dependent Variable: (DV) is the result from the change made in the experiment.

11. 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.
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.

12. 4. Data and 5. Conclusions
4. DATA – Gather data and analyze results. (displayed in graphs or tables)
Quantitative data is represented by measurements
Qualitative data is represented by descriptions.
5. CONCLUSIONS - Data from the experiment can SUPPORT or REJECT the hypothesis.

13. Retest
In order to verify the results, experiments must be retested. (Multiple trials must be done)

14. EXAMPLE #1.
After studying about recycling, members of John’s biology class investigated the effect of various recycled products on plant growth. John’s lab group compared the effect of different aged grass compost on bean plants. Since decomposition is necessary for release of nutrients, the group hypothesized that older grass compost would produce taller bean plants. Three flats of bean plants (25 plants/flat) were grown for 5 days.
The plants were then fertilized as follows:
Flat A: 450g of three-month-old compost;
Flat B: 450g of six-month-old compost;
Flat C: 0g of compost.
The plants received the same amount of sunlight and water each day. At the end of the 30 days the group recorded the height of the plants (cm).
Ind/Manip variable is
Dep/Resp variable is
Control is
Constant is

15. EXAMPLE #2
Jackie read that Aloe vera promoted healing of burned tissue. She decided to investigate the effect of varying amounts of Aloe vera on the regeneration of planaria (worm). She bisected the planaria to obtain 10 parts (5 heads and tails) for each experimental group. She applied concentrations of 0%, 10%, 20% and 30% Aloe vera to the groups. Fifteen mL of Aloe vera solutions were applied. All planaria were maintained in a growth chamber with identical food, temperature, and humidity. On day 15 Jackie observed the regeneration of the planaria parts and categorized development as full, partial, none.
Ind/Manip variable is
Dep/Resp variable is
Control is
Constant is

16. DEVELOPMENT OF SCIENTIFIC KNOWLEDGE
Goal of science = understand universe without bias
Inferences = assumption/conclusion based on observations

17. Theory How are THEORIES formed?
A scientific theory is an explanation of things or events based on knowledge gained from many observations and investigations. It is not a guess
Scientific Theories join together well supported and related hypotheses.
Theories can be changed if new evidence presents itself. (testing & revising theories is a continuous process)

18. Law
While experimenting we may observe the same behavior all the time, and therefore be able to predict this behavior will always occur in the future
Law-a generally observed behavior
Describes the relationship but does not explain as to why the behavior occurs!
(ex. law of conservation of matter or gravity)

19. The Difference Between a Theory and a Law
Laws predict what will happen
Theories explain why something happens
Models are an explanation of how phenomenon occur and how events and data are related.
Can be visual, verbal, or mathematical