Metric to English and Vice-versa

Unit Conversion What if you are given a measurement with certain unit and you need to express that same measurement with different units? You do this with unit conversion. You are not changing the value. Just expressing it in a different way.

Unit Conversion Metric to English or vice versa English to English Metric to metric When converting into different units, we must use a conversion factor. A conversion factor tells how many of a unit is equal to one another.

Conversion Factors 1m = 3.28 ft 1 mi = 5280 ft 1 mi = 1.6 km 1 in = 2.54 cm 1 lb = 10 N (newton) 1 kg = 2.2 lbs 1 cm 3 = 1 mL 1 gal = 3.79 L 1 m = yard 1 hour = 3600 s Degree Fahrenheit to degree Celsius, vice versa ̊C = (5/9)(F – 32) or ̊ F = (9/5) (̊C) + 32

Dimensional Analysis Objectives: SWBAT Perform conversion of SI units using dimensional analysis.

Dimensional Analysis The technique of converting between units is called dimensional analysis.

How to do Dimensional Analysis Step 1: Put your given over 1. Step 2: use a unit multiplier What you want What you have (put the numbers in) Step 3: Multiply the entire top; divide by the entire bottom.

Unit Multiplier We use the conversion factors to make unit multipliers (UM). A UM is a fraction that is always equal to 1. It allows you to cancel the variables you don’t want, so that you are left with only the ones you want.

Example Conversion factor: 12 inches = 1 foot and 1 foot = 12 inches Unit Multiplier:

Write down the UM for the following Conversion Factors 1)1m = 3.28 ft 2)1 mi = 5280 ft 3)1 mi = 1.6 km 4)1 in = 2.54 cm 5)1 gal = 3.79 L 6)1 kg = 2.2 lbs 7)1 cm 3 = 1 mL

Steps to Solve Problems 1) Write the conversion factor 2) write unit multiplier 3) use dimensional analysis technique.

Example: How many miles are there in 10 km? 6.2 mi

Example How many liters are there in 250 gallons?

V = 250 gal x L gal V = 950 L

More Example I inch = 2.54 cm; How many inches in 250. centimeter? The two unit multipliers are 1inor 2.54 cm cm1 in

d = 250. cm x 1 in cm d = 98.4 in.

Problems- Metric to English Conversion 1) How many gallons are in 39 L? 2) How many centimeters are in 16 inch? 3) Convert 8m to ft. 4) Convert 4.5 lbs to kg. 5) Convert 16 m to ft.

Ans. 1) 10. gal 2) 41 cm 3) ft 4) kg 5) m

Convert 1)2055 grams to pounds 2)500 gal to ml.

English to Metric & Metric to metric 1) how many gallons are in 5 liters? 2) How many kilograms are in 598 grams? 3) How many pico - seconds are in 12 seconds? 4) How many inches are in 5.00 cm? 5) How many kilograms are in 150. Ibs? 6) How many inches are in 5.00 m?

Metric Conversion (use correct no. of sig. figure in your answer) 1) 1 mm = __________ m 2) 1 km = __________ m 3) 1 m = __________ cm 4) 1 m = __________ km 5) 1 cm = __________ μm 6) 5.0 mm = __________ m 7) 15 km = __________ cm 8) 1μm = __________ km

Do not use this technique in future to avoid confusion – use dimensional analysis Metric – to - Metric Conversion When converting from a smaller unit to a larger unit, move the decimal point to the left or you divide. (Ask yourself a question – Am I expecting a large or smaller number than the given one? In this case it is smaller) Ex: Convert 457 mL to hL 457 mL = hL

Classwork Learn the metric chart by heart and by soul and recreate one now!

Metric – to - Metric Conversion cont. When converting from a larger unit to a smaller unit, move the decimal point to the right or you multiply. Example: Convert kilometers to centimeters km = cm