我非常热心地替你狗了一下。。。here is the answer

Sometimes in the fall the moon really can look
orange and yellow. If you observe closely, though, you'll find that the
in the fall, when the moon is right overhead, it looks pretty white. And
in the winter, when the moon is close to the horizon, it can look pretty
orange. Here's what's going on.
The first thing that you have to understand is that there are different
kinds of light. Green light, for instance, is different than red light.
Blue light is different than yellow light. The main difference is that
different colors of lights have different wavelengths. Light travels in
waves, and the distance from one peak of a wave to another is called the
wavelength. Blue light has a very short wavelength, and red light has the
longest.
The second thing to understand is that the air in our atmosphere acts
like a filter. It filters out short wavelength light, and scatters the
short wavelengths around. The short wavelengths are the blue ones. The
greens, yellows, and reds come through. That's why the sky looks blue.
All the blue light is bouncing around the air before it comes down, so the
sky looks blue.
At night, when the moon is right overhead, it looks white. White light
is made up of all different colors of light, including blue. When the
moon is right overhead, it comes straight through the atmosphere, so not
much of the blue light gets scattered. But when the moon gets close to
the horizon, it isn't coming at you straight on. It's kind of slanting at
us, and it's going through a lot more air. The more air the white
moonlight has to go through, the more chance for the short wavelength
(blue) light to get scattered out. The green light is pretty short too,
so it gets filtered out too. What's left is the red and yellow light.
And that's why you only see the red and yellow light when the moon gets
close to the horizon, and that's why the white moon looks red and yellow
whenever it is about to rise or set.

所有跟帖： 

• ok, i will try to explain to her.....thank you very much. -felicia1- ♀ (0 bytes) () 08/05/2009 postreply 14:41:43

• good luck~ :-) -洋葱头儿妈妈- ♀ (0 bytes) () 08/05/2009 postreply 14:42:38

• 再问： -felicia1- ♀ (156 bytes) () 08/05/2009 postreply 15:00:23

• if you take every question from cc seriously, you'll -洋葱头儿妈妈- ♀ (131 bytes) () 08/05/2009 postreply 15:20:07

• hoho, she didn't ask me those questions. i am the one who is cur -felicia1- ♀ (0 bytes) () 08/05/2009 postreply 15:22:35

• Very educating. I am not smarter than a 5th grader. -篱笆08- ♀ (0 bytes) () 08/05/2009 postreply 14:49:57