Pg. 8-19

 Scientific method  make observations  Do experiments  Create models/theories  Explain results/predict new answers

 Hypothesis – EDUCATED guess about how variables are related  Scientific law – RULE of nature that sums up related observations to describe a pattern in nature.  Scientific theory – EXPLANATION based on many observations supported by experimental results.

1. Measurement – a comparison between an unknown quantity and a standard. 2. Precision vs. Accuracy a. Precision – the degree of exactness of a measurement. b. Accuracy – how well the results of a measurement agree with the “real” or accepted value measured by competent experimenters. WS 27-28

 Instruments must be used correctly  Measurements must be made as precise as the instrument allows.  Scales should be read with one’s eye directly above the measure. See pg. 13

 Identify variables  Change one factor at a time  Independent variable – factor that is changed or manipulated  Dependent variable – factor that is measured and depends on the independent variable

 Line of best fit – a line drawn as close to all the data points as possible.  See Plotting Line Graphs pg. 16

 When the line of best fit is a straight line, the dependent variable varies linearly with the independent.  The relationship can be written as an equation. y = mx + b Y-intercept is b Slope is m

 Slope is the ratio of the vertical change to the horizontal change.  To find slope, select two points, A and B, far apart on the line.  Vertical change/rise = Δ y  Horizontal change/run – Δ x m = rise/run = Δ y/ Δ x

 If y gets smaller as x gets larger, then Δ y/ Δ x is negative, and the line slopes downward.

 Graph is not in a straight line  Quadratic relationship between two variables  Exists when on variable depends on the square of another See equation pg. 17

 Graph is a hyperbola where one variable depends on the inverse of the other.  See pg. 18 y = a/x