The Relations of the Sun to the Earth

Teacher’s Story

“Whether we look or whether we listen,
We hear life murmur or see it glisten.”

—Lowell.

All this murmuring and glistening life on our earth planet has its source in the great sun which swings through our skies daily, sending to us through the friendly ether his messages of light and warmth—messages that kindle life in the seed and perfect the existence of every living organism, whether it be the weed in the field or the king on his throne.

At sunrise this heat which the sun sends out equally at all times of day and night, is tempered when it reaches us because it passes obliquely through our atmosphere-blanket, and thus traverses a greater distance in the cooling air. The same is true at sunset; but at noon, when the sun is most directly over our heads its rays pass through the least possible distance of the atmosphere-blanket and, therefore, lose less heat on the way. It is true that often about three o’clock in the afternoon is the hottest period of the day, but this is because the air-blanket has become thoroughly heated; but we receive the most heat directly from the sun at noon.

The variations in the time of the rising and the setting of the sun may be made a most interesting investigation on the part of the pupils. They should keep a record for a month in the winter; and with this as a basis, use the almanac to complete the lesson. Thus, each one may learn for himself which is the shortest and which the longest day of the year. There is a slight variation in different years; the shortest day of the year when this lesson was written, as computed from a current almanac, was the 22d of December; it was nine hours and fourteen minutes long. The longest day of the year was the 22d of June, and it was fifteen hours and six minutes in duration. On the longest day of the year the sun reaches its farthest point north and is, therefore, most nearly above us at mid-day. On the shortest day of the year, the sun reaches its farthest point south and is, therefore, farther from the point directly above us at mid-day than during any other day of the year.

Also the movement of the sun north and south is an interesting subject for personal investigation, as suggested in the lesson. Through quite involuntary observation, I have become so accustomed to the arc traversed by the points of sunrise as seen from my home, that I can tell what month of the year it is, by simply noting the place where the sun rises. When it first peeps at us over a certain pine tree far to the south, it is December; when it rises over the reservoir it is February or October; and when it rises over Beebe pond it is July. Only at the equinox of spring and fall does it rise exactly in the east and set directly in the west. Equinox means equal nights, that is, the length of the night is equal to that of the day.

So vast is the weight of the sun that the force of gravity upon its surface is so great that even if it were not for the white-hot fireworks there so constantly active, we could not live upon it, for our own weight would crush us to death. But this multiplying the weight of common objects by twenty-seven and two-thirds to find how much they would weigh on the sun is an interesting diversion for the pupils, and incidentally teaches them how to weigh objects, and something about that mysterious force called gravity; and it is also an excellent lesson in fractions.