Unit Conversion Bellwork 6 feet = 1.83 meters 5 gallons = 18,900 mL 120 lbs = 54,545.5 g 75 mins = 0.052 days 2.3 miles = 3,701.5 meters 2,264.7 in = 57.5 meters

Measurement WCHS Chemistry

Measurement A comparison to a standard Ex: foot How were horses once measured? Hands

S.I. Units (System International) A universally accepted standard for all math and science measurements L = liter measures volume g = gram measures mass C = celsius Measures temperature m = Meter Measures length or distance

S.I Unit Conversions k. H. D. b. d. c. m. Kilo hecto deka m,L,g deci centi milli Move the decimal the desired number of places! King Henry drank bottles of delicious chocolate milk

50 cm ________________ km Practice k H D b d c m 50 cm ________________ km 15 L = _________________ mL

Measured Values vs. Counted Values IMPORTANT!!! All measured values contain some degree of error! Counted values DO NOT contain any error Ex: if you count 5 sheep, you have exactly 5

Degree of Error Ex: Balance, stopwatch, graduated cylinder, ruler All measure, so all have error! As some point you have to guess or round

At Some Point You have to Guess... When? Estimate to 1/10th the smallest place of the device (THE NEXT SPOT YOU CAN’T SEE) The limits of the instrument tell you how to round Ex: someone ran the 100m dash in 12.986548528655 sec? NO! Why or why not? You’re limited by your device

Precision in Measurement Area equation = l x w Calculation #1 Calculation #2 Calculation #3 Area equation = ½ b x H Calculation #1 Calculation #2 Calculation #3