1 The Nature of Science

2 1–1 What Is Science? Science is a process of inquiry, asking questions, which is subject to change and revision. The goal of science is to investigate and understand the natural world.

3 Scientific thinking begins with observation, the process of gathering information about events or processes in a careful, orderly way. Observations generally involves using the senses

4 Inference – a logical interpretation of observations based on prior knowledge and experience

5 Observation vs Inference List 3 Observation and 3 Inferences

6 Observation vs Inference List 3 Observation List 3 Inferences

7 Observation vs Inference List 3 Observation List 3 Inferences

8 Two types of data: –Quantitative data: expressed in numbers, obtained by counting or measuring. –Qualitative data: descriptive and involves characteristics that can’t usually be counted.

9 1-2 How Scientists Work SCIENTIFIC METHOD While there are no fixed steps, it generally involves: 1)MAKE OBSERVATIONS: observations utilize the senses to gather information.

10 2)ASK A QUESTION: observations may lead to unanswered questions. 3)FORM A HYPOTHESIS: A good hypothesis predicts a relationship between cause and effect. - A hypothesis is a proposed scientific explanation for a set of observations. -Scientific hypotheses must be proposed in a way that enables them to be tested.

11 4)SET UP A CONTROLLED EXPERIMENT: A controlled experiment involves two groups: a)Variable (Experimental) group: A variable is the factor of an experiment that can change.

12 –Controlled (constant) variables: same for both the control and variable group. –Manipulated (independent) variable: variable that is deliberately changed. –Responding (dependent) variable: changes in response to the manipulated variable (what happened).

13 b)Control group: group that receives no experimental treatment, the standard against which results are compared.

14 5)RECORD AND ANALYZE RESULTS: keeping a written record of observations and data. 6)DRAWING A CONCLUSION: Use evidence to determine whether the hypothesis was supported or refuted.

15 7)REPORTING RESULTS: Results are only useful if they are made available to other scientists for peer review.

16 But why can’t I test it? It isn’t ethical (many animal studies, disease studies, etc.) It can’t be controlled We lack the technology

17 ‘I have a theory’ vs. Scientific Theory Common usage of theory = guess, prediction (hypothesis) A theory is a well-tested explanation that unifies a broad range of observations. –No theory is considered absolute truth. –As new evidence is uncovered, a theory may be revised or replaced.

18 Scientific Laws A statement of fact meant to explain, in concise terms, an action or set of actions. It is generally accepted to be true and universal, and can sometimes be expressed in terms of a single mathematical equation.

19 The biggest difference between a law and a theory is that a theory is much more complex and dynamic. A law governs a single action, whereas a theory explains an entire group of related phenomena.

20 A scientific law is like a slingshot. A slingshot has one moving part--the rubber band. If you put a rock in it and draw it back, the rock will fly out at a predictable speed, depending upon the distance the band is drawn back. An automobile has many moving parts, all working in unison. An automobile is a complex piece of machinery. Sometimes, improvements are made to one or more component parts. A new set of spark plugs that are composed of a better alloy that can withstand heat better, for example, might replace the existing set. The function of the automobile as a whole remains unchanged. A theory is like the automobile. Components of it can be changed or improved upon, without changing the overall truth of the theory as a whole. ANALOGIES