PUT YOUR PXRF TO WORK: A K-12 E&O MODULE LEVERAGING PLANETARY ROVERS AS ROBOTIC GEOLOGISTS TO TEACH ABOUT EARTH AND PLANETARY SCIENCES

NASA’s Mars Science Laboratory mission (MSL) has produced amazing results and is the current embodiment of the pursuit of NASA’s most publicly recognized objective, the exploration of Mars, seeking evidence for past or present life, ultimately to include a manned mission. MSL, with its emblematic rover Curiosity, is thus an excellent tool to use to engage K-12 students in the subjects of Earth and planetary sciences. We have prepared a module to do just this and presented it to middle and high school Earth sciences classes and high school chemistry and physics classes. The module has also been piloted as part of a planetary geology lab exercise for an introductory level college geology course.

It is easy to make the case in the K-12 classroom for planetary rovers in general, and Curiosity specifically, to be viewed as “robotic geologists”. After all, the close-up camera on Curiosity was named to reflect this connection, the Mars Hand Lens Imager, equating the camera to one of the basic field tools carried by every geologist. We describe the relationships between other Curiosity instruments and those utilized in geology labs (e.g., X-ray diffraction and ChemMin). While we use the term “robotic geologist”, we also emphasize that Curiosity collects data, but human geologists are necessary to analyze and interpret the data.

Our module has three main elements:

(1) Students are introduced to the principle of uniformitarianism, and then they examine analog rock samples paired with actual photos taken by rovers of the geology of Mars.

(2) Students are introduced to how X-ray fluorescence spectrometry works at a level consistent with their understanding of chemistry, and given chemical criteria for distinguishing “Earth-like” (MORB), “Mars-like” (alkali basalt), and “Moon-like” (FeTi basalt), and then they actively participate in a portable X-ray fluorescence spectrometry (pXRF) demonstration using qualitative analysis of three analog basalt lava samples to recognize what composition type each belongs to.

(3) To further utilize a strength of pXRF to address a kind of problem the public commonly brings to geologists, we also have them examine two samples that look like iron meteorite candidates, and then analyze them to see which is a meteorite (with a significant Ni peak) and which is a pseudo-meteorite or “meteorwrong” (no Ni peak).