1. Unit Conversions

2. Converting Between Units In The Metric System In the science we always use the metric system of measurement, instead of the English system that America uses. The metric system uses standardized SI (Systeme Internationale) units. You will be expected to know how to convert between units in the metric system.

3. The Conversion Table millions 100 thousands 10 thousands thousands hundreds tens ones. tenths hundredths thousandths 10 thousandths 100 thousandths millionths Mega __ kilohectodecaunits. decicentimilli __ micro M__khDunits.dcm__μ

4. SI Units MeasurementSI Unit distancemeter (m) timesecond (s) volumeLiter (L or l) massgram (g) weightNewton (N) temperature° C

5. Metric Conversions Set up equation: Given x (new units/old units) Given is what was given to you in the problem (see ex) Write the symbols for the units. Let the denominator = 1 Let the numerator = 10 exp To find the exponent, start at the old units on the numberline, count the number of spaces to the new unit. The number of spaces = the exponent. Don’t count the decimal space! If counting  the exponent will be negative. If counting  the exponent will be positive.

6. Metric Conversion - example 1 Convert 875 cm to hm. What is your given? 875 cm 875 cm x (10 exp hm / 1 cm) Starting at cm, how many spaces to hm? 4 spaces in  direction (so the exponent will be -4) 875 cm x (10 -4 hm / 1 cm) =.0875 hm How to use your calculators for scientific notation

7. Metric Conversion - example 2 Convert 12 g to μg. What is your given? 12 g 12 g x (10 exp μg / 1 g) Where is g located on the numberline? At the units place. Starting at the units place, how many spaces to μg? 6 spaces in  direction (so the exponent will be +6) 12 g x (10 6 μg / 1 g) = 12,000,000 μg or 1.2 x 10 7 μg

8. Dimensional Analysis Metric conversions are an example of dimensional analysis (DA). DA is one of the most useful tools for a scientist. Given x “conversion fraction”. The conversion fraction is how many of the old units are in 1 of the new units (or vice versa) A unit in the numerator will cancel if it is also in the denominator of the conversion fraction. A unit in the denominator will cancel if it is also in the numerator of the conversion fraction. Examples

9. Dimensional Analysis and Metric Conversions Questions 1.Convert 31.56 km to dm 2.Convert 1.32 µg to cg 3.Convert 40.0 ks to ms 4.Convert 125 N to hN 5.Convert 4522 DL to ML 6.Convert 6.72 m to mm 7.Convert 75 miles/hr to m/s 8.Convert 2.5 m/s 2 to miles/hr 2