The summer before my senior year in college, I interned at WGBH in Boston as part of the online division for NOVA. Having been a big fan of the show as a child, it was a dream come true. I was even able to earn my first byline by penning a web extra, "Moving Targets." I didn't do the animation, but I wrote the script and mockuped each screen for the art department. Here's the link, and here's the original introduction:
Determining something's radial velocity-how fast it is moving towards or away from you-is quite easy. By taking note of something called the Doppler effect and making close observations of the light from stars, we're able to tell not only if those stars are moving to or away from us but how fast they're moving.
You can find out how it's done and also determine stellar velocities yourself with [this activity]."
Answers to science questions, brief lessons, and ideas for teachers and students.