Metric Conversion – A Quick Tutorial
Conversion between metric and standard units can be tricky since the units of distance, volume, area and temperature can seem rather arbitrary when compared to one another. Although the metric system (using SI units) is the standard system of measure in most parts of the world many countries still use at least some of their traditional units of measure. In North America those units come from the old British system.
Distance, Volume, Area and Temperature.
John Wilkins, pictured left, in 1668, published an essay proposing a decimal system of measurement.
Below are practice test questions for the metric system similar to what you will find on a standardized test.
When measuring distance the relation between metric and standard units looks like this:
|0.039 in||1 millimeter||1 inch||25.4 mm|
|3.28 ft||1 meter||1 foot||.305 m|
|0.621 mi||1 kilometer||1 mile||1.61 km|
Here, you can see that 1 millimeter is equal to .039 inches and 1 inch equals 25.4 millimeters.
When measuring area the relation between metric and standard looks like this:
|.0016 in2||1 square millimeter||1 square inch||645.2 mm2|
|10.764 ft2||1 square meter||1 square foot||.093 m2|
|.386 mi2||1 square kilometer||1 square mile||2.59 km2|
|2.47 ac||hectare||1 acre||.405 ha|
Weight and Mass
When measuring weight and mass the relation between metric and standard units looks like this:
|.035 oz||1 gram||1 ounce||28.35 g|
|2.202 lbs||1 kilogram||1 pound||.454 kg|
|1.103 T||1 metric ton||1 ton||.907 t|
It is important to note that in science, the metric units of grams and kilograms are always used to denote the mass of an object rather than its weight.
In predominantly metric countries the standard unit of temperature is degrees Celsius while in countries with only limited use of the metric system, such as the United States, degrees Fahrenheit is used. This chart shows the difference between Fahrenheit and Celsius:
|0° Celsius||32° Fahrenheit|
|10° Celsius||50° Fahrenheit|
|20° Celsius||68° Fahrenheit|
|30° Celsius||86° Fahrenheit|
|40° Celsius||104° Fahrenheit|
|50° Celsius||122° Fahrenheit|
|60° Celsius||140° Fahrenheit|
|70° Celsius||158° Fahrenheit|
|80° Celsius||176° Fahrenheit|
|90° Celsius||194° Fahrenheit|
|100° Celsius||212° Fahrenheit|
As you can see 0° C is freezing while 32° F is freezing. Similarity 100° C is boiling while the Fahrenheit system takes until 212° F. To convert from Celsius to Fahrenheit you need to multiply the temperature in Celsius by 1.8 and then add 32 to it. (x° F = (y° C*1.8) + 32) To convert from Fahrenheit to Celsius you do the opposite. First subtract 32 from the temperature then divide by 1.8. (x° C = (y° -32) / 1.8)
Similarly, when measuring volume the relation between metric and standard units looks like this:
|3034 fl oz||1 milliliter||1 fluid ounce||29.57 ml|
|.0264 gal||1 liter||1 gallon||3.785 L|
|35.314 ft3||1 cubic meter||1 cubic foot||.028 m3|
1. Convert 10 kg. to grams.
a. 10,000 grams
b. 1,000 grams
c. 100 grams
d. 10.11 grams
2. 1 gallon = _________ liter(s).
a. 1 liter
b. 3.785 liters
c. 37.85 liters
d. 4.5 liters
3. Convert 2.5 liters to milliliters.
a. 1,050 ml.
b. 2,500 ml.
c. 2,050 ml.
d. 1,500 ml.
4. Convert 210 mg. to grams.
a. 0.21 mg.
b. 2.1 g.
c. 0.21 g.
d. 2.12 g.
5. Convert 10 pounds to kilograms.
a. 4.54 kg.
b. 11.25 kg.
c. 15 kg.
d. 10.25 kg.
6. Convert 0.539 grams to milligrams.
a. 539 g.
b. 539 mg.
c. 53.9 mg.
d. 0.53 g .
7. Convert 16 quarts to gallons.
a. 1 gallons
b. 8 gallons
c. 4 gallons
d. 4.5 gallons
8. Convert 45 kg. to pounds.
a. 10 pounds
b. 100 pounds
c. 1,000 pounds
d. 110 pounds
1kg = 1,000 g and 10 kg = 10 x 1,000 = 10,000 g
1 US gallon = 3.78541178 liters
1 liter = 1,000 milliliters, 2.5 liters = 2.5 x 1,000 = 2,500 milliliters
1,000 mg = 1 g, 210 mg = 210/1000 = 0.21 g. Be careful of Choice A, (0.21 mg.)
The numbers are the same but the units are different.
1 pound = 0.45 kg, 10 pounds = 4.53592, or about 4.54 kg. When multiplying a
decimal by 10, move the decimal point one place to the left.
1 g = 1,000 mg. 0.539 g = 0.539 x 1000 = 539 mg.
4 quarts = 1 gallon, 16 quarts = 16/4 = 4 gallons. Conversion problems are easy to get confused. One way to think of them is which is larger – quarts or gallons? Gallons are larger, so if you are converting from quarts to gallons the number of gallons will be a smaller number. Keeping that in mind, you can do a ‘commonsense’ check on your answer.
0.45 kg = 1 pound, 1 kg. = 1/0.45 and 45 kg = 1/0.45 x 45 = 99.208, or 100 pounds.