Chapter 1 Measurement

Measurements A measurement has two parts: 1. a number value Examples: 12, 3, 432, etc. 2. a unit Examples: meters, seconds, ninth graders List two examples of measurements in your notes, different from what is listed above.

Two Systems of Measurement English (“American”) System - used for everyday measurement in the United States International System of Units or Metric System - used for everyday measurement in most other countries and for scientific measurements

The Metric System Base unit of length Base unit of mass Base unit of volume

Converting in the Metric System Move the decimal point: Move decimal to the right Move decimal to the left

The Metric System Prefixes to memorize: pink packet p. 2 List the 4 prefixes in order of size, starting with the smallest: milli < centi < [base unit] < kilo If you have a bunch of pennies, will you have more milligrams of pennies or grams of pennies? List the 4 prefixes in order of NUMBER of each, starting with the smallest number: # of kilo < # of [base unit] < # of centi < # of milli

The Metric System Summary milli < centi < [base unit] < kilo # of kilo < # of [base unit] < # of centi < # of milli Example: 0.001 kilometer = ? meter = ? centimeters = ? millimeters

Converting in the Metric System SIZE compared to base unit NUMBER compared to base unit Example kilo- (k) [base unit] centi- (c) milli- (m) 1000x larger 1000x smaller 5 km=5000 m equal equal equal 100x smaller 100x larger 1200 cm=12 m 1000x smaller 1000x larger 8 mm=0.008 m

Accuracy and Precision Accuracy: how close a measurement is to the accepted, true value Precision: how close repeated measurements are to one another

Accuracy and Precision Are the pictures below accurate, precise, accurate and precise, or neither? 1 3 2 4

Accuracy and Precision Activity Complete with assigned partner: Everyone gets their own target With eyes closed, spin around in a circle twice then dot the target sheet 4 tries each Goal = to mark as close to the bull’s-eye each try

Accuracy and Precision Activity Walk around the room and mark 4 different people’s targets on the bottom with one of the following: A = Accurate P = Precise AP = both accurate & precise N = neither Accurate or Precise