The human body was used as the first form of measurement. Have you ever wondered why the length of a foot is called a "foot?" It is because people actually used the length of their foot to determine a certain length. The same goes with a "hand," which was a measurement based on how wide your hand was, including the fingers. An "inch" was determined by the width of a thumb.
Obviously these ways of determining measurements were not very accurate, as people had different sized feet and hands. Likewise, an acre was determined by how far an ox could plow a field in one day. The conditions were not consistent, though many times pretty close. Thus, scientists came up with permanent forms of measurement that would be the same for all.
*The official system in the U.S. is the customary system.*
Below are some basic conversions.
Length
- 1 foot = 12 inches
- 1 yard = 3 feet = 36 inches
- 1 rod = 5-1/2 yards
- 1 furlong = 40 rods = 220 yards = 660 feet
- 1 mile = 8 furlongs = 1,760 yards = 5,280 feet
- 1 league = 3 miles
Area
- 1 square foot = 144 square inches
- 1 square yard = 9 square feet = 1,296 square inches
- 1 square rod = 30-1/4 square yards
- 1 acre = 160 square rods = 4,840 square yards = 43,560 square feet
- 1 square mile = 640 acres
Capacity
Dry Measure
- 1 quart = 2 pints
- 1 peck = 8 quarts
- 1 bushel = 4 pecks
Liquid Measure
- 1 gill = 4 fluid ounces
- 1 pint = 4 gills = 16 ounces
- 1 quart = 2 pints = 32 ounces
- 1 gallon = 4 quarts = 128 ounces
- 1 barrel = 31-1/2 gallons
Cooking Measure
- 1 teaspoon = 1/6 fluid ounce
- 1 tablespoon = 3 teaspoons = 1/2 fluid ounce
- 1 cup = 16 tablespoons = 8 fluid ounces
- 1 pint = 2 cups
- 1 quart = 2 pints
- 1 gallon = 4 quarts
Volume
- 1 cubic foot = 12 inches x 12 inches x 12 inches = 1,728 cubic inches
- 1 cubic yard = 27 cubic feet
Depth
- 1 fathom = 6 feet
- 1 cable = 120 fathoms = 720 feet
Weight
- 1 dram = 27.344 grains
- 1 ounce = 16 drams = 437.5 grains
- 1 pound = 16 ounces
- 1 hundredweight = 100 pounds
- 1 ton = 2,000 pounds
Temperature
- 32 degrees Fahrenheit = the point at which water freezes
- 212 degrees Fahrenheit = the point at which water boils
- 0 degrees Celsius = the point at which water freezes
- 100 degrees Celsius = the point at which water boils
To convert from Celsius to Fahrenheit
Multiply by 1.8 and add 32
Example: F = 1.8 x 100C + 32 / F = 212
To convert from Fahrenheit to Celsius
Subtract 32 and divide by 1.8
Example: C = 212F - 32 / 1.8 / C = 100
Activity Using Weights and Measures
Cartesian Diver
Materials:
- 2-liter soda bottle
- Medicine dropper
- Water
- Large glass of water
Instructions:
- Place the medicine dropper into the glass of water.
- Squeeze the bulb to let some of the air bubbles out.
- Release the bulb and watch as the water moves in to replace the air that was removed.
- Release the dropper and watch it barely float in the water. If it floats too high, squeeze it to remove more air. If it sinks, then squeeze out a drop of water and let it take in some air.
- Fill the 2-liter soda bottle to the top with water.
- Place the dropper into the bottle and put on the cap.
- Gently squeeze the bottle and the dropper will sink to the bottom.
- Release the bottle and the dropper rises back to the top.
