Chapter 1 Scientific Thinking & Reasoning (pgs. 18~25) Objective: I can use the scientific method in order to construct and test a valid hypothesis through a well- designed experiment *Be wise about how you take notes

Science Explains how things work or why things are the way they are (YOU must learn how to explain!!!) NOT just a memorization of facts You must learn HOW to make discoveries ROY G. BIV Why see only those colors?

Scientific Reasoning Deductive reasoning: use general principles to come up with a specific prediction –Deduction: conclusion drawn from general idea Inductive reasoning: use specific situations to come up with a general idea –Induction: conclusion drawn from specific case General Ideas Deduce Aha! I know who did it! Or I know what will happen! Specific Cases Induce Big Ideas / Principles Law of Gravity, Evolution

Deductive or Inductive? Since Mark and Kelly answered all the questions in the chapter (even the ones not assigned) and did well on the test, I will do the same. –Inductive Since Mr. Hsu said if you answer all the questions in the chapter (even the ones not assigned) you will do well on the test, I will do it. –Deductive

Deductive or Inductive? Because a warmer climate is much more favorable to humankind than a cooler climate, global warming is not to be feared. –Deductive I know that God exists because the world is so well ordered by scientific law and this order is probably not due to chance alone. –Inductive

Scientific Reasoning cont’d Three important notes to summarize: 1) Scientific discovery usually = inductive Most scientific discoveries = general principles First attempted induction (possible explanation) = –Can you make a deduction without someone making an induction first? NO 2) Inductions (generally)comes before deductions 3) Logic requires a structured, methodical interplay between both, which leads to… hypothesis

Scientific Process (aka Scientific Method) Set of steps to carry out scientific investigations methodically Note: exact steps vary, but general principles are the same –Might learn something different / more accurate / more difficult in college –If anything, what you learn might change

Scientific Process How do we start? Observation (can have Questions, Research…) …what’s next? Hypothesis: proposed explanation (how/why) –Must be 1) specific, 2) testable, and an 3) explanation –Don’t confuse hypothesis with prediction (what happened in picture?) NOT an educated guess!!! Experiment (test hypothesis) –Note: well-designed experiment = controlled exp –How many groups? 2: control group & experimental grp Control group = serves as comparison (normal) Experimental group = receives treatment –There should be only 1 difference between these two groups Conclusion (analyze/evaluate data: graphs)

Parts of the Experiment Variables = factors that can change –Independent Variable: “the cause”  x-axis One that scientist (YOU) change or manipulated Should be the only difference between groups –Dependent Variable: “the effect”  y-axis What responds or changes due to independent var. What is measured at the end –Controlled Variables: “constants” all other factors that should be kept the same DO NOT CONFUSE WITH CONTROL GROUP –Interfering Variables = other “indep. var.” that you don’t want Good Experiment has few interfering var. Perfect Exp. has no interfering (but not possible) Abstract (can’t touch)

After Conclusion If wrong, re-write hypothesis  do new exp. If correct, test again & communicate…why? Theory: collection of tested and proven hypotheses that explain a phenomenon –EXPLAIN how or why (upgraded hypothesis) –Proven based on experimentation –Can change or be disproven Scientific Law: a statement that always applies under the same conditions –States what it is –Based on observation

A Visual Representation of the Scientific Process

How can we get CLOSER to the truth?