Pillars of the Earth Sciences: explanation and scientific understanding: How do the earth and planetary sciences explain phenomena in the world compared to other sciences? What role does understanding by scientists and students play in explanation? Project description: I will connect the practice of the earth sciences to recent philosophical models of what constitutes an explanation. The earth and planetary sciences study causes of events and phenomena from billions of years ago to the present, as well as the underlying biological, chemical and physical mechanisms and laws. I will compare contrasting kinds of explanations, such as mathematical models based on Newtonian physics versus graphical syntheses by Humboldt and others. I will also study how scientists arrive at these explanations by research activities and what role research activity experiences play in gaining understanding. Finally, I will study how we can improve the communication and education of earth and planetary sciences by explicit teaching of how earth science explains and how we gain understanding.