Winter and the Sun? They're closer than you might think.

When this discussion came up in class, I was shocked at how little I knew about the relationship between the proximity of the sun and the seasons on Earth.  I knew about axial tilt and the reason for summer and winter, but I didn't realize that Earth is closer to the sun in the northern hemisphere's winter.  I always knew that Earth has a very slightly elliptical orbit, but I never knew that it was enough to make much of a difference. 

This website explains everything fairly well:

http://www.space.com/3304-earth-closest-sun-dead-winter.html

Earth is closest to the sun in early January and farthest from the sun in early July.  For those people living in the southern hemisphere, it is true that Earth is closer to the sun in summer.  But for those of us here in the United States, or anywhere in the northern hemisphere, we're experiencing winter at that time. 

Picture was taken from: http://www.ngawhetu.com/Resources/TheRhythmicSky/index11.html

One way that you could teach this so that kids can remember and understand is to take them outside, where there is plenty of room, and replicate this picture with the students.  Have one student standing in the middle with a big yellow ball (the sun), and have another student hold a globe (Earth).  "Earth" will move around in a circular orbit around the sun.  Have other students hold representations of the seasons (a big snowflake for winter, a red maple leaf for fall, etc.).  Ask "Earth" to move a little closer to "The Sun" when he or she gets to "Winter."  It may not be as exact as the picture, but it gets them moving, and they may remember it better if they're acting it out.

This is a picture of the analemma, which is the pattern of the position of the noontime sun over the course of a year.  The highest point is during the summer solstice and the lowest point is during the winter solstice.  The figure-eight pattern is due to Earth's elliptical orbit.

I'm sure that some people knew this, but I sure didn't.  It just goes to show that there are a LOT of things that I still don't know, and there's always room to learn!