On October 23rd, 2014, we updated our
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SUBJECTIVE VS. OBJECTIVESubjective: outcomes are based on the tester’s feelings and opinions. (Used in the arts) ex: “I don’t like you because I think you’re ugly…”Objective: a judgment based on fact, not on personal feelings or opinions. (Science must use this) ex: “I’ll buy this car because it gets the best gas mileage.”
SCIENTIFIC METHOD1. Recognize a problem2. Make and educated guess-a hypothesis-about the answer3. Predict the consequences of the hypothesis4. Perform experiments to test predictions5. Formulate the simplest general rule that organizes your finding based on your hypothesis, predictions and results of experimentation We use this general method daily though we may not think of it “WEAR THE PANTS”
VARIABLES IN EXPERIMENTATIONIn any experiment, there can be many variables. The important thing is to only change one variable in an experiment at a time, if you want to isolate true cause and effect of experimentation.
THINK-PAIR-SHAREGive an example of changing one variable at a time.
HOW GOOD IS A MEASUREMENT? “Mr. Basso, how well do I have to measure?” (story of the plumb-level) Accuracy vs. Precision (Think-pair-share: what’s the difference?) share your definitions on the board
PRACTICING ACCURACY Think-Pair-ShareA block of brass that weighs 500 grams is weighed on a digital scale. Students practice their use of a scale. The students report their results:Student 1: measures 497 gramsStudent 2: measures 501 gramsStudent 3: measures 503 gramsStudent 4: measures 497 gramsStudent 5: measures 496 grams Are these student’s measurements Accurate?
PRACTICING PRECISION Think-Pair-ShareStudents measure a length of wood with a measuring tape. It’s known measurement is 16’ 1-1/16” long:Student 1: measured 16’ 1-1/8”Student 2: measured 16’ 1-1/8”Student 3: measured 16’ 1-1/16”Student 4: measured 16’ 1-1/16”Student 5: measured 16’ 1-1/8” Are these students precise?
EXAMPLE OF ACCURACY AND PRECISION
EXAMPLE OF ACCURACY AND PRECISIONAccuracy: How close do you get to the actual measure/markPrecision: Is the measurement repetitively close to each other
In science we need to try to be both accurate and precise!