1. Ch 5 Measurements
Scientific measurements are based on the metric system. This is a decimal based system that uses a system of prefixes to relate the magnitude of the quantity. It is essential that you are able to work fluently in the metric system.

3. Metric Quantities The standard unit of length is the meter (m)
The standard measure of mass is the gram (g)
The standard unit of Temperature is Celsius (C) or Kelvin (K) Tk = Tc
The standard unit of volume is either:
Cubic centimeters (cc) 1 m = 1,000,000 cm3
Liters (L) L = 1000 mL
Milliliters (mL) mL = 1 cc

4. Converting metric/metric Converting metric/english
How many decimal places do I move it??
Please do not ask this question or use this technique. We will use a system of conversion called dimensional analysis. It converts values using factors of one that have both the known and unknown quantities in them. We will use the same technique for m/m and m/e conversions.

5. Conversion Factors
A conversion factor is a ratio of one that includes the known and unknown quantities.
First find an equality between the known and unknown km = 1.0 mi
Turn it into a ratio with the unknown desired quantity in the numerator km
Multiply the ratio by the known value
1.0 mi

6. Example #1 Convert a 10.0 km race to miles
Known quantity is 10.0 miles
Known equality is km = 1.0 miles
The ratio used is mi
Use initial quantity x conversion factor = answer
10.0 km x mi = mi
1.609 km
1.609 km

7. Rounding Off & Significant Figures
It is important to be honest when reporting a measurement, so that it does not appear to be more accurate than the equipment used to make the measurement allows. We can achieve this by controlling the number of digits, or significant figures, used to report the measurement.
Use the rules of significant figures whenever you are reporting a calculated value derived from collected or given data

8. Rules for Significant Figures
Non-zero integers are always significant. The number has four significant figures
Zeros within a number are always significant. Both 4308 and contain four significant figures.
Zeros that do nothing but set the decimal point are not significant. Thus, 470,000 has two significant figures.
Trailing zeros that aren't needed to hold the decimal point are significant. Thus, 4.00 has three significant figures.
Zeros prior to a number less than 1 are not significant. Thus, has 3 significant figures

9. How many significant figures?
15.02
four
15.0
three
100
one
276.2
four
400.0
8.9
two
4002

10. Rules for Calculating Add/Subtract
Round the answer to the least significant decimal place
Multiply/Divide
Round your answer to the number of significant figures contained in the least precise number

11. Example #2 Calculate 1.302 + 0.26 = Answer = 1.56