2.  Know exact property to be measured  Have standard to compare what you are measuring  Have method to make comparison

3.  Qualitative ◦ No numerical info. ◦ Based on opinion  Quantitative ◦ Provides actual numerical information ◦ Can be supported

4.  SI Base Units   QuantityUnit Name & Symbol  Masskilogram, kg  Lengthmeter, m  Timesecond, s or sec  Quantitymole, mol  TemperatureKelvin, K  Electric currentampere, A  Luminous intensitycandela, cd

5.  Derived Units   QuantityUnit Name & Symbol  Areasquare meter, m 2  Volumecubic meter, m 3 ( liter, l)  ForceNewton, N  PressurePascal, Pa  EnergyJoule, J (calorie, cal)  PowerWatt, W  Voltagevolt, V  Frequencyhertz, Hz  Electric chargecoulomb, C

6.  Metric Prefixes   QuantityPrefix & Symbol  Millionmega, M  Thousandkilo, k  Hundred hector, h  Tendeca, da  Tenthdeci, d  Hundredthcenti, c  Thousandthmilli, m  Millionthmicro, u  Billionthnano, n  Trillionthpico, p

7.  Precision ◦ Measure of how close a set of measurements are to each other not necessarily to actual value  Accuracy ◦ How close a measurement is to the true and correct value

8.  Difference between accepted value & experimental value  % Error = ( ∣error∣ ÷ accepted value) x 100