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Scientific Measurement:. Qualitative vs. Quantitative Qualitative = descriptive, non-numerical. ex. : the mornings are getting very cold. Quantitative = numerical, definite measurement ex. : the temperature was 65°F this morning. Scientific Measurement:.
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Scientific Measurement: Qualitative vs. Quantitative Qualitative = descriptive, non-numerical. ex. : the mornings are getting very cold. Quantitative = numerical, definite measurement ex. : the temperature was 65°F this morning.
Scientific Measurement: • Accuracy- close to the true value • Precision- close within measurements • % Error- describes how close your data is to the accepted value Accepted – Experimental x 100 Accepted Value
Scientific Measurement: Metric • Know your metric relationships! • kilo -hecta - deca -(base) - deci - centi – milli ( 103 - 102 -101 - (1) – 10-1 - 10-2 - 10-3) • King Henry Died By Drinking Chocolate Milk
Scientific Measurement: Scientific Notations • Used for measurements that are very large or very small. • Describes a number to the power of 10. (N x 10X) Where N : 1≤ N < 10 X (+) = large number X (-) = small number • Ex. 1.5 x 104 = 1.5 x 10-4=
Scientific Measurement: SI Units • Standard Unit of measure • Metric based measurements Length = meter (m) Volume = derived from length (m3) Mass = kilograms (kg) Density = mass/volume (g/cm3) Temperature = Kelvin (K) Time = seconds (s) Amount of substance = mole (mol)
Scientific Measurement: Significant Figures • Used to express the accuracy of a number. • Used for “measured” numbers. • Rules for determining Sig. Figs. • All non-zero numbers are significant • Captive zeros are significant • Leading zeros are not significant • Trailing zeros are significant if a decimal is present
Chapter 4 Notes: Problem Solving • Steps to Problem Solving Approach: • Analysis: determine starting point and plan steps required to get a solution. • Calculate: conduct appropriate calculations based on plan. This may require multiple steps. • Evaluate: Review answer to see if it seems reasonable.
Chapter 4 Notes: Problem Solving • Conversion Factors- a ratio of equivalent measurements ( 1 inch = 2.54 cm) • Dimensional Analysis- the technique for solving problems using unit conversions based on conversion factors Ex. 6. 42 inches = ? cm
Chapter 4 Notes: Problem Solving • Multi-step Problems – use more than one conversion factor: ex. 5 days = ? minutes • Complex Problems- involves ratios of two units: ex. .45 Km/hrs = ? m/s Golden Rule for conversions…always show your work!