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In the last physics lesson, the teacher seemed to have to explain the Doppler effect for quite a long time to some people before they understood it. So, being the nice, considerate, thoughtful person I am, I decided out of the goodness of my golden heart to explain the Doppler effect for future reference using animation (actually, I thought it would be a fun thing to do anyway). For those of you who are confused about what the Doppler effect has to do with anything, it's red shift and blue shift. So it is relevant to the lesson.

The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. 

"http://yt.cl.nr/_mCC-68LyZM" If you drop a heavy object and a light object simultaneously, which one will reach the ground first? A lot of people will say the heavy object, but what about those who know both will land at the same time? What do they think? Some believe both objects have the same gravitational pull on them and/or both fall to the ground with the same constant speed. Neither of these things is true, however. The force is greater on the heavy object and both objects accelerate at the same rate as they approach the earth, i.e. they both speed up but at the same rate.

Having reluctantly accepted mining on their ancestral lands, the indigenous people who live beside the nation's biggest uranium mine could soon watch see their industrial interloper depart.