Presentation on theme: "The Metric System A decimal system of units for measurements of length, mass, time, etc. System International (SI) units – a superset of seven units from."— Presentation transcript:
1The Metric SystemA decimal system of units for measurements of length, mass, time, etc.System International (SI) units – a superset of seven units from which all others can be derived.
2SI Units Quantity Name of Unit Abbreviation Length meter m Mass kilogramkgTemperaturekelvinKTimesecondsAmount of SubstancemolemolElectric currentampereALuminous intensitycandelacd
3Common Prefixes Prefix Symbol Numerical Value Mega M kilok1,000 = 1 x 103centic0.01 = 1 x 10-2millim0.001 = 1 x 10-3micro= 1 x 10-6
4Conversion Factor A relationship between two quantities. Important – both quantities should include units.Can be:metric-to-metric.English-to-English.English-to-metric.
5Conversion Factor1 foot = 12 inches100 cm = 1 m1 inch = 2.54 cm
6Dimensional Analysis Uses units with the numerical values. All units should cancel except those that are desired for the answer.My method is sometimes referred to as the “fence-post” method.Remember – answers should be rounded to the proper number of significant figures!
8Dimensional Analysis 0.054 meters = ? centimeters Why are these set-ups wrong?
9Dimensional AnalysisMulti-step problems can be done either all at once or one step at a time.Ex) 2.50 feet = ? cm
10Problem-SolvingRead the problem carefully and highlight any numbers and their units. Determine what is known and what is to be solved for.Plan out your course of action. What conversion factors are needed? Write them down.
11Problem-SolvingSet-up and organize the problem in a neat and logical fashion making sure units cancel for each step.Calculate your answer following proper mathematics and round to the proper number of significant digits.Check your answer and work.
13Dimensional Analysis 55 miles per hour = ? meters per second How long will it take to travel 5.0 km at this speed?
14Measuring Mass and Volume Matter = anything that occupies space and has mass.The SI unit of mass is the kilogram.Volume is a derived unit and is the amount of space occupied by matter.Based on the SI system, the standard unit would be a meter x meter x meter or cubic meter (m3).
15Measuring Mass and Volume However, this is too large to use in practical uses.1 milliliter (mL) is defined as a cube that measures 1 cm x 1 cm x 1 cm.Thus, 1 mL = 1 cm3 or 1 cc.
16Volume ConversionsA block measures 12 inches by 6.5 inches by 2.5 inches. What is the volume of this block in Liters?
17TemperatureTemperature is the measurement of the amount of heat a substance has.Heat flows from warmer to colder objects.SI unit is the Kelvin.Metric unit is Celsius.English unit is Fahrenheit.