Slide 1

Unit 1

Methods of Science:HypothesisLawTheoryModelLimitations of Science

Read Section 1.2 prior to viewing the slides.

Section 1.2: Science: Reproducible, Testable, Tentative, Predictive, and Explanatory

Topics for Unit 1Basic characteristics of science (1.2)Hypothesis testable and reproducibleLaw summary of many observationsTheory tentative attempt to explain observationsModel attempt to explain abstract ideas with more familiar scale examplesLimitations of science why dont we always know the answer?

HypothesisA hypothesis is an educated guess that is testableHypotheses (plural of hypothesis) are tentative explanations of phenomena that can be tested by further experimentationExample: If a plant receives fertilizer it will grow larger than a plant that does not receive fertilizer.

Testable vs. Untestable HypothesesThe ability to test a hypothesis is a key element of its viability.A testable hypothesis is one for which experiments may be designed to determine absolutely whether the hypothesis is false. Such a hypothesis typically involves some sort of quantitative (numerical) determination.An untestable hypothesis is one for which no determination may be made as to its validity. Examples of untestable data include emotions, perceptions, etc.The fertilizer/plant hypothesis on the previous page could be tested if the experiment is well designed both watered equally, same sunlight, same seed stock, etc.

LawA law is a brief summary of large amounts of scientific dataA law does not attempt to explain why something happens it simply states that it doesA law is universal under the stated sets of conditions it has always been found to be trueExamples: The law of the conservation of mass, the law of gravity, the law of conservation of energy

TheoryA theory provides a detailed possible explanation as to why something is observedTheories are tentative they can be modified or discarded based upon new evidenceTheories provide predictive capabilityExamples: Theory of Relativity, Kinetic-Molecular Theory

ModelA model attempts to explain abstract phenomena with tangible approachesA model is often used to help picture the description of a process provided by a theoryExample: The processes in a gas can be envisioned as similar to billiard balls hitting each other this lends a tangible visualization to the kinetic molecular theory

Interaction of Hypothesis, Law, Theory, and ModelSometimes you may get the perception that these concepts are explored in a certain order, for example:Observation Hypothesis Theory

In reality, though, there is no hard and fast rule as to the order in which these concepts are considered in scientific work.

Limitations of ScienceIt might seem that with the usually perceived cold, hard fact view of science that everything would have an absolute answer.This is not the case due to the fact that science cannot control all of the variables.Example: Consider man-made global warming, which is widely accepted now, but not by everybody. The number of variables to be understood is immense.