Explanations, Science, Life In order to be scientific, a claim must have which of these characteristics? TentativeUses math Makes testable predictionsBased on rules of logic Concerns the supernaturalConcerns the natural world RepeatableObservable evidence Hard to understandConcerns only the present time

Homework Syllabus, student info sheet, lab contract due Monday for A, Tuesday for F.

Finishing PLORNT What IS science? Thinking about what you already knew from before and what you’ve learned from PLORNT, with your table partner, come up with a good definition of science that makes sense to you.

Finishing PLORNT Science is vast and complicated, but here’s one way of summing it up that I think is pretty darn good. Science is both a body of knowledge about the natural world, and the process by which human beings develop that knowledge. Natural explanations of natural phenomena are developed by rigorously and empirically testing them, and these explanations are always based upon logical consideration of observable evidence, are always tentative, and are always constructed by community consensus.

Explanations Addressing another question that was on the pretest… about a common misconception! Laws, theories, observations, and facts Scientific language

Facts & Observations AN OBSERVATION: A data point that is a description of something you sensed. Decide with your partner: which of these are observations? This lizard has two black stripes. The chemical solution we made smells like rotten eggs. The reason why the shark attacked the human was because it thought he was a seal. The crystals in the sample are small, white, and cubic. These crystals in the sample are salt.

Facts & Observations A FACT: An observation that has been made repeatedly. “Fact” does not mean “truth” or “proven” in science! Which of these are facts? The sky is blue. Because shorter wavelengths of light are absorbed and scattered by air molecules while longer wavelengths of light (like red light) pass straight through, it is the shorter wavelengths of light that reach human eyes, which makes the atmosphere appear blue.

Explanations What science REALLY wants are explanations of observations and facts. The two most important scientific explanations: theories and laws.

Laws and Theories With your partner, come up with and write down your best definitions of a scientific law, and a scientific theory. Also think of an example of each. I’ll ask each table to report your results. (If you had me last year, please work with somebody else who did also.)

Atomic Theory: All matter is made of atoms. Theory of Evolution: Groups of organisms change over time. Cell Theory: Living things are made of cells. Ideal Gas Law: PV=nRT Germ Theory of Disease: Communicable diseases are caused by germs. Newton’s Second Law of Thermodynamics: F=ma Hardy-Weinberg’s Law: p + q = 1, (p + q) 2 = p 2 + 2pq + q 2 Plate Tectonics Theory: Plates moving in relation to each other cause earthquakes, volcanoes, continental drift, mountains, and ocean trenches. Ohm’s Law: I = V/R Newton’s Law of Gravitation: F = G((m 1 m 2 )/r 2 ) Quantum Theory of Gravitation: Gravitation is caused by gravitons, 2-spin elementary particles

Explanations LAW: Describes patterns in relationships between observable quantities. THEORY: Explains how or why something in nature happens the way it does. Theories never become laws, laws never become theories. Example: gravity. What do you notice that’s different from your definitions?

Explanations What’s different from your definitions? WHY do you think there are differences? “I don’t remember things” or “I’m not that smart” or similar answers are, I’ll tell you right now, incorrect.

Scientific Language It’s a hard habit to break! The idea of “proven” and the nature of evidence is hard to get over, I know. I want to take today to discuss it a bit, before we start learning the science itself!

Scientific Language Give me your ideas: What, in science, do you think can never be 100% proven?

Similarities and Differences Facts are observations. Laws describe facts. Theories explain facts and laws. Theories and laws require the same volume of evidence. Neither of them is ever random or a guess. They are the pinnacle of scientific achievement, scientists DREAM of constructing one!