Scientific Method

Steps in the Scientific Method Observation (Identify Problem) Hypothesis (Predicting) Experiment Data Collection (Analyze & Infer) Conclusion Retest

Observations Identify a problem or question based on observations Gathered through your 5 senses Taste, Smell, Touch, Hearing, Vision Observations will occur prior to and after identification of a problem Example of an observation: Noticing that many salamanders near a pond have curved, not straight, tails

Hypothesis A suggested solution to the problem. Must be testable Sometimes written as If…Then…statements Predicts an outcome Example of a hypothesis: The salamanders have curved tails due to a pollutant in the moist soil where they live.

Experiment A procedure to test the hypothesis. Gathering data under controlled conditions – conducting a controlled experiment Based on comparison of a control group with an experimental group

Control Group Controls are NOT being tested What is the Purpose of a Control – situation where variables are left alone (as normal as possible). Controls are NOT being tested Controls are used for COMPARISON

Independent vs. Dependent Variables: Experiment (cont’d) Independent vs. Dependent Variables: Independent - The factor that is manipulated (changed) by the researcher Dependent - The factor that is observed/measured because it is expected to be “dependent” on the manipulation of the independent variable Graphing independent vs. dependent Dependent (y-axis) Independent (x-axis) “y depends on x”

Experiment (cont’d) A good or “valid” experiment will only have ONE independent variable! (one manipulated by the researcher)

Data Collection Any and all measurements and observations gathered from the experiment May be quantitative (numbers) or qualitative (descriptive)

Data Collection (cont’d) Must be organized Can be organized into charts, tables, graphs, or maps

Conclusion Conclusion- The answer to the hypothesis based on the data obtained from the experiment Collected and organized data must be Analyzed and Inferences must be made! Analyzing – process of determining whether data are reliable, whether they support or refute the hypothesis Inferring – conclusions made on the basis of facts or premises rather than on direct observation

Retest… It is best to make several trials with each independent variable – Retest! Retesting verifies the results.

What is required for the experiment to be valid?: Two groups are required - the control group & the experimental group There should be only one independent variable Retesting!

COMMUNICATION Sharing information is essential to the scientific process Subject to examination and verification by other scientists (others setting up the same experiment should get the same results) Allows scientists to build on the work of others Publish findings in journals or at scientific meetings

REVIEW: Solving a Problem 1) Identify a Problem based on Observations 2) Form a Hypothesis about the problem (if…then…) 3) Design Experiment to test the hypothesis 4) Collect Data 5) Form Conclusion 6) Retest

SCIENTIFIC LAWS Are statements of fact meant to explain, in concise terms, an action or set of actions. Are generally accepted to be true and universal, and can sometimes be expressed in terms of a single mathematical equation. Are similar to mathematical postulates. They don’t really need any complex external proofs; they are accepted at face value based upon the fact that they have always been observed to be true.

Give me some examples of scientific laws! Newton’s Three Laws of Motion The Laws of Thermodynamics Boyle's law of gases The law of conservation of mass and energy Hooke’s law of elasticity Galileo's law of free fall Kepler's three laws of planetary motion Newton's law of gravitation

SCIENTIFIC THEORIES This one is perhaps the most “controversial” of the terms we’ve looked at so far. Why? Simply because people mistake a scientific theory for the every day use of the term “opinion”.

SCIENTIFIC THEORIES A "theory" is not an insult (as in the silly saying "it's just a theory"). A theory is simply the most elaborate form of consistent scientific knowledge not yet disproved by experiment. In experimental sciences, a theory can never be "proved", it can only be "disproved" by experiment. This is precisely what makes a theory scientific. A statement that cannot be disproved by experiment may still be highly respectable but it's simply not part of any experimental science.

                     All of these theories are well documented and proved beyond reasonable doubt: The theory of evolution The theory of relativity The atomic theory The quantum theory . A theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers. One scientist cannot create a theory; she can only create a hypothesis.

L A W (fact) THEORY HYPOTHESIS When proven that it always works When supported over time Only call on those with misconceptions The rest of what we will be doing is exploring the validity of this HYPOTHESIS