Length of Day

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Length of Day

 

the interval of time between sunrise and sunset, during which the sun is above the horizon. The length of day depends upon the geographic latitude of a place and upon the inclination of the sun. At the equator, the length of day is constant and equals 12 hours. In the northern hemisphere, the length of day is more than 12 hours during the positive inclination of the sun (that is, in the spring and summer) and less than 12 hours during the negative inclination of the sun (in the autumn and winter). At the equinoxes (spring and autumn), the day equals the night (if one does not consider refraction) everywhere on the earth. The longest day is the summer solstice and the shortest is the winter solstice. Within the polar circles, the length of day in the summer can exceed 24 hours (the polar day), and at the poles daytime lasts six months.

References in periodicals archive ?
SITs focus on day-to-day operations, including school day length, attendance, GED test logistics, identification and assignment of inmates to school, transfers, etc.
EDSTAC originally recommended the concept of the fish gonadal recrudescence assay (GRA), whereby breeding fathead minnows (Pimephales promelas) of both sexes would first be transferred to "winter phase" (short day length and low temperature) conditions to inhibit spawning.
Birds can detect as little as a 10-minute difference in day length, which causes a reaction by the brain on their pituitary gland.
By extending the day length and quality of light I was able to produce better quality plants.
Assuming a nutritionally balanced diet and healthy birds, the three factors affecting egg production are age, cold and day length.
Location in the southwest of England is a result of local initiative, but the mild climate, lavish rainfall and relatively balanced day length render the peninsula one of the best locations in Western Europe for the experiment.
But if you move closer to the equator you have that day length all year.
The seeds of the summer ecotypes germinate and the plants develop when the temperatures are high (27-32 [degrees] C) and day length is long (12.
They suspected environmental factors such as temperature or changing day length could cue the monarchs to the change in season.
Professor Sam Martin, from the University of Aberdeen, said: "We know that the change in day length during spring is important for the Atlantic salmon to know when is the right time to start making the journey.
Alteration in HPG axis activity and transition through breeding stages has been strongly linked to changes in day length in many species (Hahn et al.
Choose from hyperspeed, full day length time-lapse skies, or slower more relaxing afternoons, sunsets and even nights.