Wednesday, August 3, 2011
"This is mission control, you are clear for landing."
The quote above is an approximation of the first thing that came out of my mouth when I saw the scanning electron microscope (SEM). I was sure I had seen this in old movies of Apollo space explorations, but it turns out that the machine is a lot more contemporary than I imagined (less than 20 years old). And even for having that much age, I was amazed at the power.
An SEM is used to take high resolution pictures of objects. They can typically study features that are 10's of nanometers (about 1/1000 the thickness of a human hair) with striking clarity. To the left is an SEM image of an "trojan particle" from a paper I co-authored about 10 years ago. In photo "b", each of the smaller particles are less than 50 nm, yet they you can see them with ease. (The SEM used to take this picture had a different interface than the one we used this week, which is why I was so surprised by the control panel).
Using the SEM, we looked at the finer features of a nickel, examined the topography of different types of paper, and got up-close and personal with a fly. Part of the reason I teach science is to help students discover how cool it can be. We can actually see what a fly's eye looks like! Show me a student who doesn't find that interesting...