Measurements Integrated Science Chapter 2 Section 2 Pages 14-21

I. Units of Measurement - SI (le Système Internationale d’Unités) units  Metric System  French phrase

SI units 1. All scientists use the same units in order to have a standard for understanding each other 2. Base SI units (Table 1-1, page 15) a. Length – meters (m) b. Mass – kilograms (kg) c. Time – seconds (s) d. Intensity of light – candella (cd) e. Temperature – Kelvin (K) f. Current – ampere (A) g. Amount of substance – mole (mol)

B. Making Measurements 1. Types of measurements a. Quantitative measurements – numerical values with units, amount how much  scientific tools used to measure the quantities - Examples: Length – straight line distance between to points Mass – measure of amount of matter in an object Volume – measure of space or capacity, ( Length x Width x Height ) Weight – force with which gravity pulls on matter Time – measurable period during which an action occurs

B. Making Measurements b. Qualitative measurements – relating to quality or kind, things not measured with numbers - Examples:Colors, Odors, Taste

C. Significant Figures – the digits in a measurement that are known with certainty 1. Accuracy – Closeness to the true value 2. Precision – repeatability of measurement  How reproducible is the measurement? If you measure again will you get the same measurement?

When measuring… Keep one more decimal place, than the tool actually measures.