Students and Pluto

It's the week before midterms, and I have been worried about the knowledge level of my students. They really put my mind at ease for a while today, as they derailed my review session briefly to discuss the New Horizons probe launched for Pluto.
They knew its speed. They compared it to escape speed and orbital speed. They reminded each other of the difference between a projectile and a satellite. They sidetracked to the Stardust capsule that brought comet dust back to earth, parachuting safely to the Utah salt flats last week.

They knew things about New Horizons I didn't.
1) It is powered by 24 pounds of plutonium dioxide.
2) There were protests over this. [eyes roll]
3) It carries "the first student-built science instrument to be sent to another planet," a dust-counting device designed and built by University of Colorado students.
4) It also carries some of Clyde Tombaugh's ashes.

Okay, that last one chokes me up just a little.

Incidentally, if you are unfamiliar with Celestia ("The free space simulation that lets you explore our universe in three dimensions") and Google Earth, I highly recommend you download them and play with them. Especially science teachers with access to computers in the classroom. My students seem much more familiar with the scale and the names of the bodies in the solar system this year because of Celestia. And it's just fun to play with.