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Unit 1—Fundamental Skills. Scientific Method. Ask a question about something in Nature. Formulate a hypothesis about the question. This is a testable guess, prediction, or statement . Perform an experiment . Take data and then analyze your data. Draw a conclusion.
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Scientific Method • Ask a question about something in Nature. • Formulate a hypothesis about the question. This is a testable guess, prediction, or statement . • Perform an experiment. Take data and then analyze your data. Draw a conclusion. • Revisit your hypothesis. Revise it if necessary and re-do the experiment. With verification over time a hypothesis becomes a theory/law.
Experimental Variables • Independentvariable is a specific factor you purposely change or allow to change while observing to see if another variable is affected by it. • Dependentvariable is a specific factor you observe to see how it is influenced by changes in the independent variable. • Controlledvariable is one or more factors in an experiment that you keep constant.
Measurements • Measurements are a form of information or data. They typically consist of a number and a unit of measure. • A set of measurements is accurate if the average is close to a known standard or true value. • A set of measurements is precise if the range (high – low) of values is small—that is, the values are close together.
Precision of a Measuring Tool • The precision of a measuring instrument (in contrast to precision of a set of measured numbers) relates to the smallest level or fineness of measure that you can read. • In general, the maximum precision of an instrument is about 1/10th of the smallest mark or division on your instrument. Example: On our meter sticks, the smallest mark is a mm mark. Maximum precision of our meter stick then is 1/10th of a mm.
Numbers • In physics we handle both huge and very small numbers. To handle the wide range of such numbers, we often express them in scientific notation: 6.02 x 1023 for example. • Often we use prefixes to represent certain powers of ten: 3000 m = 3 km where k or kilo- means x103. • We use SI units for mass (kg), distance (m), time (s), and a few other fundamental quantities.
For the Unit 1 Test, know… • SI units (mass, distance, & time) • Prefixes (from micro- to kilo-) • Unit conversions • Graphing rules • Slope calculation • Accuracy & precision • Types of experimental variables • Scientific method