On reflection, explaining the seasons is probably by far the most complicated and difficult of the "elementary" science concepts. One could easily spend a whole week teaching the concepts necessary to understand the correct explanation for the seasons. It's no surprise that most people haven't "gotten" it. Light bulbs, on the other hand... never mind.
A large globe with two solar cells attached to it works. One solar cell is attached to the equator, the other near the pole, so that they are tangent to the surface of the globe. Attaching a large voltmeter to each cell, then illuminating the globe with a projector, shows that the tilt makes a difference in how much energy is available. I haven't done it, but saw it done on a kid-science TV show once. It was a cool demo.
Topic for conversation: How important is it, really, that most people understand the seasons? We no longer use the motions of the Sun, Moon, and stars for navigation or timekeeping, so most people have no practical use for this information. The seasons will happen just the same whether they are fully understood or not. Is this a topic worth spending a lot of instructional time on? Or in an over-packed school year of physics, is there something else more worthy of our limited instructional time, like electrical safety, global warming, lasers, medical imaging, or transistors? And whatever happened to Simple Machines? Their loss is deplorable, as is anything else "applied." Why don't we ditch electric and magnetic fields (a topic best understood at advanced levels)in favor of basic semiconductors or liquid crystal displays? What physics topics should be considered "essential" today?
Vickie Frohne
vfrohne@ben.edu
-----Original Message-----
From: Forum for Physics Educators [mailto:PHYS-L@list1.ucc.nau.edu]On
Behalf Of John M Clement
Sent: Thursday, February 24, 2005 11:22 AM
To: PHYS-L@LISTS.NAU.EDU
Subject: Re: In the Private Universe
One of the things that has been ignored in discussion of the seasons
is that it is a cognitively difficult thing to understand.
*lots of good stuff snipped*
A useful thing would be to have a model of the earth where the
students could observe the amount of light intensity/area. I would
propose a globe with either a light sensor imbedded in it attached to
a meter, or a translucent section that provides light in the interior,
and a peephole that students could observe the light intensity. Then
students could see the effect of the angle. Then they could explore
how the angle and the illumination changes with the seasons.