This diagram shows the seasonal relationships between the sun and the earth. The normally recommended angle for a fixed solar collector is. and Insolation. Understanding Earth's relationships with the sun leads us directly of daylight vary in length through the seasons of the year, as well as from. Only $1/month. 3 reasons for the seasons Relationship between angle of insolation and temperature Relationship between latitude and angle of insolation.
One revolution accounts for a year of what we call "time," and the fact that each year has an extra quarter of a day explains why we need a leap year once every 4 years.Seasons and the Sun: Crash Course Kids 11.1
For some reason, as we get closer to the sun, our speed slows down slightly and then quickens again as we get further away. There is a tremendous difference between the energy that is received by a surface that is square to the sun's rays and one that is at an angle. This is why solar collectors that are far from the equator must be tilted to absorb the maximum amount of radiation for as many hours as possible during the day.
Years ago our parents or some elementary school teacher taught us that the earth goes around and around and that the sun shines on us from 93 million miles away. This is why we have day and night.
What they may or may not have Figure The earth spins on a tipped axis as it moves around the sun. This is why we have changes in seasons. On June 21, although we are actually further from the sun, we are tilted toward it — that's if we live in the northern hemisphere.
On December 21, we are tipped away from the sun, so its rays don't hit us directly. On June 21 — the summer solstice — we in the northern half of the world are tilted most toward the sun so it hits us most directly.
This is the day when we receive sunlight for the longest amount of time. On December 21, we are tilted farthest away from the sun. Then we get the fewest hours of sunshine and those rays we do get hit us at a pretty flat angle.
6(i). Earth-Sun Relationships and Insolation
On March 21 and September 21 — the spring and fall equinoxes — there are equal amounts of sunlight and darkness. The Tropic of Cancer The Tropic of Capricorn The graph also shows that the seasonal winter to summer variation in day length increases with increasing latitude. Figure 6i-3 below describes the potential insolation available for the equator and several locations in the Northern Hemisphere over a one-year period.
The values plotted on this graph take into account the combined effects of angle of incidence and day length duration see Table 6h Locations at the equator show the least amount of variation in insolation over a one-year period. These slight changes in insolation result only from the annual changes in the altitude of the Sun above the horizon, as the duration of daylight at the equator is always 12 hours.
The peaks in insolation intensity correspond to the two equinoxes when the Sun is directly overhead. The two annual minimums of insolation occur on the solstices when the maximum height of the Sun above the horizon reaches an angle of The most extreme variations in insolation received in the Northern Hemisphere occur at 90 degrees North.
During the June solstice this location receives more potential incoming solar radiation than any other location graphed. At this time the Sun never sets. In fact, it remains at an altitude of From September 22 September equinox to March 21, March equinox no insolation is received at 90 degrees North.
During this period the Sun slips below the horizon as the northern axis of the Earth has an orientation that is tilted away from the Sun.
The annual insolation curve for locations at 60 degrees North best approximates the seasonal changes in solar radiation intensity perceived at our latitude.
Maximum values of insolation are received at the June solstice when day length and angle of incidence are at their maximum see Table 6h-2 and section 6h. During the June solstice day length is 18 hours and 27 minutes and the angle of the Sun reaches a maximum value of Minimum values of insolation are received during the December solstice when day length and angle of incidence are at their minimum see Table 6h-2 and section 6h.