posted by Gerson .
1. There is a common misconception about why the Earth is cold in the winter and warm in the summer. Some believe that this is because the Earth, in its elliptical orbit, is closer to the Sun in the summer and farther away in the winter. The argument is that being closer to the Sun we get more sunlight and being farther away we get less. While it is true that this plays a role in the seasons on the Earth (the changing distance to the Sun causes about a +/- 3% change in the amount of sunlight that we receive) this theory suffers from several flaws, the most striking of which is that the Earth is closest to the Sun in early January---almost exactly the opposite of where it should be if the changing distance to the Sun was the cause of the seasons.
In this lab we will investigate the two primary contributors to the changing seasons on the Earth, the angle that the sunlight strikes the surface of the Earth and the length of time that the Sun is visible. Both of these issues are due to the fact that the Earth is tilted on its axis. There are other factors that contribute to the seasons, wind, ocean currents, altitude, etc. but we will ignore these effects for the time being.
As we begin our investigation, the first thing that we need to do is determine the latitude of our observer on our planet. The latitude can be done by adjusting the tilt of the planet until the incoming sunlight is perpendicular to the surface of the planet on the summer solstice. (This is when the planet is farthest to the left; the words "Summer Solstice" will appear just above the warning "Sizes and distances not to scale".)
What is the latitude of our observer?
That is the latitude of observers that have the sun overhead on the summer solstice (June 21)