Scribbles
By Bob Curtis, Local Secretary
November 2013

It is now November and we are looking forward to our distinguished speakers event on December 7th and the scholarship reading on January 26th, as well as the usual first and third Friday dinners, and Saturday lunch at Krogh's on November 16th.

In September, we saw the arrival of autumn with the equinox and now we see the end of daylight saving time for a few months. Ever since I was told by my Latin teacher that "equinox" means that day is as long as night, I have been fascinated by the fact that this is just not the case and intrigued to find out why. Actually, at the equator, day is always longer than night. Significantly north or south of the equator, equal days and nights occur on the winter side of the equinox date. There are two reasons for this. One is an issue of definition and the second is because light does not always travel in straight lines. Sometimes matters of definition can lead to fun and interesting puzzles: which is heavier, a pound of gold or a pound of feathers? Does a tree falling in the forest make a sound if there is no one there to hear it? As to the equinox, the definition of day is when any part of the sun is above the horizon. Depending on the distance from the earth to the sun, which changes during the year, the diameter of the sun takes about 32' of arc. Those who calculate the equinox consider day to be when the center of the sun is on the horizon. This means the time of sunrise is 16' of arc too early. When the sun is not directly overhead, its light is refracted when it enters the atmosphere. This bending accounts for another 34' of arc when the sun is at the horizon, making the day longer both at sunrise and sunset. Thus a total of 50' of arc must be taken into account. At Hackensack's latitude, night and day were not equal until September 26th this year. (A pound of feathers is heavier than a pound of gold because a pound of gold is defined to be 12 Troy ounces while a pound of feathers is defined as 16 Imperial (avoirdupois) ounces. On the other hand, a pound of lead weighs a little more than a pound of feathers because it displaces less air. Sound is traditionally defined as the stimulation of the nerves of the ear and in this sense there has to be a hearing ear to have a sound; a more modern (objective) definition of sound is that which could cause this stimulation, i.e., the changes in the density of air.)