Subject: micrometeorite lesson--will it work?

I'm a science teacher in the state of Washington, and I'm in the midst of the micrometeorite lesson suggested by NASA, and yourself (and by a presenter at a recent workshop I attended). These little particles are also known as Brownlee particles, after Don Brownlee of the Astronomy Department at the University of Washington. I had him for classes back in college, so I gave him a call to get more information. The interesting thing is that he doesn't think the procedure will work! He thinks that pollution from industrial sources (smelting, refining, welding, etc.) would produce a lot of particles in the 100 micron range, which would be picked up in the experiment. Apparently the number of micrometeorites that size hitting any given area in a year is fairly small, with 10 micron ones being more plentiful.

Basically, it seems that he thinks that there are a number of teachers out there running an astronomy lesson to collect debris from welding. Are we? My students will be collecting samples from drainspouts in the area; Once we've got some good samples, we're going to send it in to the UW, and see what Dr. Brownlee thinks. Apparently some analysis with an electron microscope can tell him about the elemental content, and that would let him know if it was terrestrial or extra terrestrial.

I enjoy the idea of the lesson, and really hope that it will work, but it might be worth encouraging this kind of test in other parts of the country to see how sound it is. Let me know what you think, and If you'd like to post this letter anywhere, I'd love to hear responses and/or queries!

Thanks!

Re: micrometeorite lesson--will it work?