430 likes | 829 Views
Units of Measurement. Measurement. You are making a measurement when you Check you weight Read your watch Take your temperature Weigh a cantaloupe What kinds of measurements did you make today?. Standards of Measurement.
E N D
Measurement You are making a measurement when you • Check you weight • Read your watch • Take your temperature • Weigh a cantaloupe What kinds of measurements did you make today?
Standards of Measurement When we measure, we use a measuring tool to compare some dimension of an object to a standard.
Learning Check From the previous slide, state the tool (s) you would use to measure A. temperature ____________________ B. volume ____________________ ____________________ C. time ____________________ D. weight ____________________
Solution From the previous slide, state the tool (s) you would use to measure A. temperature thermometer B. volume measuring cup,graduated cylinder C. time watch D. weight scale
Learning Check What are some U.S. units that are used to measure each of the following? A. length B. volume C. weight D. temperature
Solution Some possible answers are A. length inch, foot, yard, mile B. volume cup, teaspoon, gallon, pint, quart C. weight ounce, pound (lb), ton D. temperature °F
Stating a Measurement In every measurement there is a • Number followed by a • Unitfrom measuring device
Number vs. Quantity • Quantity - number + unit UNITS MATTER!!
LearningCheck What is the unit of measurement in each of the following examples? A.The patient’s temperature is 102°F. B. The sack holds 5 lbs of potatoes. C. It is 8 miles from your house to school. D. The bottle holds 2 L of orange soda.
Solution A. °F (degrees Fahrenheit) B. lbs (pounds) C. miles D. L (liters)
Metric System - standards of measurement used in science Units in the Metric System • length meter m • volume liter L • mass gram g • temperature Celsius °C
Learning Check Identify the measurement in metric units. A. John’s height is 1) 1.5 yards 2) 6 feet 3) 2 meters B. The volume of saline in the IV bottle is 1) 1 liters 2) 1 quart 3) 2 pints C. The mass of a lemon is 1) 12 ounces 2) 145 grams 3) 0.6 pounds
Solution A. John’s height is 3) 2 meters B. The volume of saline in the IV bottle is 1) 1 liter C. The mass of a lemon is 2) 145 grams
International System of Units • Metric system is now revised as the International System of Units (SI), as of 1960 • Based on 10 or multiples of 10 • Used in most of the world • Used by scientists and hospitals • 7 base units Table 1-3, page 12
SI Base Units Quantity Symbol Base Unit Abbrev. Length l meter m Mass m kilogram kg Time t second s Temp T kelvin K Amount n mole mol
M V D = Derived Units • Combination of base units. • Volume (m3 or cm3) • length length length 1 cm3 = 1 mL 1 dm3 = 1 L • Density (kg/m3 or g/cm3) • mass per volume
Volume • The space occupied by any sample of matter • Calculated for a solid by multiplying the length x width x height • SI unit = cubic meter (m3) • Everyday unit = Liter (L), which is non-SI
Volume • 1 Liter is the volume of a cube 1 dm (10 cm) on a side • 1 L = 10 cm x 10 cm x 10 cm • 1 L = 1000 cm3 • 1/1000 L = 1 cm3 • 1 mL = 1 cm3 • 1 mL is about 20 drops of water or 1 sugar cube • 1 L about 1/4 of a gallon - a quart
Learning Check Match 1) length 2) mass 3) volume ____ A. A bag of tomatoes is 4.6 kg. ____ B. A person is 2.0 m tall. ____ C. A medication contains 0.50 g Aspirin. ____ D. A bottle contains 1.5 L of water.
Solution Match 1) length 2) mass 3) volume _2 A. A bag of tomatoes is 4.6 kg. _1_ B. A person is 2.0 m tall. _2_ C. A medication contains 0.50 g Aspirin. _3_ D. A bottle contains 1.5 L of water.
mega- kilo- k M 106 103 BASE UNIT deci- --- d 100 10-1 centi- c 10-2 milli- m 10-3 micro- 10-6 nano- n 10-9 pico- p 10-12 SI Prefix Conversions Prefix Symbol Factor
Metric Prefixes • Increase or decrease basic unit by 10 • Indicate a numerical value prefix = value 1 kilometer = 1000 meters 1 kilogram = 1000 grams
Prefixes that Increase A Unit Prefix Symbol Value giga- G 1 000 000 000 mega- M 1 000 000 kilo- k 1 000
Prefixes that Decrease A Unit Prefix Symbol Value deci- d 0.1 centi- c 0.01 milli- m 0.001 micro- (mu) 0.000 001 nano n 0.000 000 0001
Learning Check Select the unit you would use to measure A. Your height 1) millimeters 2) meters 3) kilometers B. Your mass 1) milligrams 2) grams 3) kilograms C. The distance between two cities 1) millimeters 2) meters 3) kilometers D. The width of an artery 1) millimeters 2) meters 3) kilometers
Solution A. Your height 2) meters B. Your mass 3) kilograms C. The distance between two cities 3) kilometers D. The width of an artery 1) millimeters
Learning Check Indicate the prefix to use for 1. A mass that is 1000 times greater than 1 gram 1) kilo 2) milli 3) mega 2. A length that is 1/100 of 1 meter? 1) deci 2) centi 3) milli 3. A unit of time that is 1/1000 of a second. 1) nanosecond 2) microsecond 3) millisecond
Solution 1. 1) kilo 2. 2) centi 3. 3) millisecond