Cumberland Times-News

March 1, 2014

What do these vital measurements mean?

Bob Doyle, Columnist
Cumberland Times-News

—  A while back, I wrote a column on how the U.S. has firmly held onto British units that the British themselves have abandoned (inch, pound, quart).

Today, I’ll take up some other important quantities and their units. My reference is “How Fast Is A Knot?”, a deck of knowledge cards by Don Root, from Pomegranate Communications with ISBN 9780764954535.

 A nautical mile is the distance North or South to change your latitude by 1/60 th of a degree. One nautical mile is 1.15 of our miles. A knot is one nautical mile per hour. Ships would put out a line with a “knot” every nautical mile.

The difficulty in using knots is that this unit is based on a ship’s motion relative to the water, rather than land.

So if a cruise ship moving south is in a current flowing to the north (Gulf Stream), the speed in knots wouldn’t be useful in determining your arrival time at the Caribbean port. (Of course, the ship would have global positioning devices that would tell the deck exactly where the ship was.)

What is a cubit, the unit in which Noah’s ark was described in Genesis? The cubit was the distance from the elbow to the tip of the middle finger. Egyptian measuring sticks show their cubit to be 20.5 inches while the Roman cubit was 17.5 inches.

So if we use the smaller cubit, Noah’s ark of 300 cubits long, 50 cubits wide and 30 cubits high would have dimensions of 437 feet long, 73 feet wide and 45 feet high.

What is a bushel? Originally, a bushel was a measure of volume for agricultural goods equal to 2,150.42 cubic inches. But the bushel has evolved into a weight measurement, that varies for each kind of produce. A bushel of barley now means 42 pounds, according to the USDA (U. S. Department of Agriculture).

There is more to the temperature scales than most books mention. Gabriel Fahrenheit set up his scale in 1724 with water’s freezing at 32 and boiling at 212.

In 1742, Anders Celsius created his scale with water’s boiling temperature at 0 degrees and its freezing at 100 degrees.

Swedish botanist Carolus Linnaeus reversed Celsius’ scale, putting freezing be 0 C and boiling at 100C, the way Celsius temperatures are used worldwide.

 Major earthquakes seem to strike every few years with devastating consequences for those near the quake’s epicenter.

The Richter scale is logarithmic so that every increase in one unit means that earthquake’s energy is 10 times larger.

In 1965, seismologists Richter and Gutenberg determined that an earthquake at 7.0 on the Richter scale would have a total energy equivalent to 475,000 tons of TNT (far larger than the atomic bombs dropped on Japan).

The earthquake with the highest Richter scale struck Southern Chile in late May of 1960 with a reading of 9.5. The energy of this quake was 316 times larger or equivalent to 150 million tons of TNT, with more energy than any hydrogen bomb tested during the Cold War.

 What is an acre? Originally, an acre was defined as the area that an oxen could plow in a day. Today, we define an acre to be 43,560 square feet. A square field that’s 208.7 feet on a side would occupy 1 acre of land. 1 square mile = 640 acres.

In Europe, areas are measured in Hectares, the area of a square field that’s 100 meters (328 feet) on a side = 10,000 square meters. 1 Hectare = 2.469 Acres.

SKY SIGHTS AHEAD: The moon is now growing in lighted width from a slender crescent in the western dusk to half full in the southwestern evening sky March 8.

The very bright planet Jupiter is high in the south as it gets dark. The planet Mars is a bright yellow point of light low in the southeast in the last hour of the evening.

The planet Saturn is best viewed in the southwestern sky at dawn, appearing to the right of the star group Scorpion (resembles a “J” in the South.)

Bob Doyle invites any readers comments and questions. E-mail him at rdoyle@frostburg.edu . He is available as a speaker on his column topics.