“Disproportionation of (Mg,Fe)SiO3 perovskite in Earth’s deep lower mantle” … say what?

I’m going to invite you to skim the following research summary from Science.

The mineralogical constitution of the Earth’s mantle dictates the geophysical and geochemical properties of this region. Previous models of a perovskite-dominant lower mantle have been built on the assumption that the entire lower mantle down to the top of the D″ layer contains ferromagnesian silicate [(Mg,Fe)SiO3] with nominally 10 mole percent Fe. On the basis of experiments in laser-heated diamond anvil cells, at pressures of 95 to 101 gigapascals and temperatures of 2200 to 2400 kelvin, we found that such perovskite is unstable; it loses its Fe and disproportionates to a nearly Fe-free MgSiO3 perovskite phase and an Fe-rich phase with a hexagonal structure. This observation has implications for enigmatic seismic features beyond ~2000 kilometers depth and suggests that the lower mantle may contain previously unidentified major phases.

I know. Me too. Even some of the words I recognize seem to be used in a way I’m not familiar with. And my spell checker went ballistic with red underlining.

But I want to tease out a few key phrases before I ask you to read a very short Huffington Post article that translates the above passage … sort of. The phrases are “previous models,” “built on the assumption,” “on the basis of experiments … we found,” “this observation has implications … and suggests.”

Sound familiar?

Perhaps those phrases remind you of this:

Our old friend, the NGSS Science and Engineering Practices

Our old friend, the NGSS Science and Engineering Practices

Now here’s a link to the story, “Earth’s Mantle Isn’t Quite What We Thought It Was, Study Shows,” that sent me to the summary in Science. What is exciting to me about this little story is what it reveals about science, about what a theory actually is — an understanding of how a particular facet of the world works, based on all the available evidence to date … something that can change but only in the face of new data — and about scientists’ willingness to continuously push against the boundaries of our understanding. The closing sentence is especially revealing. “But according to Dr. Yue Meng, another Carnegie geophysicist involved in the study, the finding ‘may significantly alter the prevailing theory of the lower mantle.'” And that’s cool!

But here’s another thing to ponder.

The kind of thinking these amazing scientists did to arrive at a new understanding of how the earth is constituted, which ultimately will make its way into updated science textbooks, can begin for your students in your classroom this year. The words and phrases in the research summary at the beginning of this post and in the popularized version published on Huffington Post for us non-scientists are words and phrases your students can learn from you in the process of doing science. They won’t get it from reading chapters in textbooks. The best way for you to lay the foundation for scientific research, or even for understanding enough science to be an informed citizen with an appreciation of the kind of thinking that underlies science, is to help students frame investigable questions and conduct inquiry-based investigations to find answers to those questions.

The scientists involved in this breakthrough study are Li Zhang, Yue Meng, Wenge Yang, Lin Wang, Wendy L. Mao, Qiao-Shi Zeng, Jong Seok Jeong, Andrew J. Wagner, K. Andre Mkhoyan, Wenjun Liu, Ruqing Xu, Ho-kwang Mao. Notice anything? What isn’t so obvious is that with the exception of Li Zhang, Wenge Yang, Lin Wang, Ho-Kwang Mao, who are affiliated with the Center for High Pressure Science and Technology Advanced Research (HPSTAR), in Shanghai, China, but who are also with American research institutions, all of the scientists involved in this study are based in the U.S. at places like Argonne National Laboratory right here in Illinois, the National Accelerator Laboratory in Menlo Park, California, and Stanford University.  Science is international. It is also collaborative. (Yay, for science teams!)

Teamwork is Essential in the Science Classroom.

Teamwork is an Essential in the Science Classroom.

We must do everything in our power to insure that all of our students have the opportunity to follow this life path, if their interests and talents incline them to it, and regardless of their socioeconomic status, their race, or their country of origin. Quite simply, all of our students need more time in the school day, and more opportunities in elementary school period, to lay the groundwork for pursuing this life choice. Only then will they be prepared to take on more challenging science in high school and to become science majors in college. And someday, because of your early encouragement, perhaps they will publish their findings in a prestigious peer-reviewed journal like Science. That’s what!

~ Penny

You can find us here.





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Filed under children as scientists, NGSS, scientist, Uncategorized

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