Tim Philpot, age 10, of Murray, Kentucky, for his question:

What is geophysics?

We borrowed "geo" from an older word for the earth. We use it in such words as geography, the study of maps; and geology, the study of minerals in the earth's crust. These are just two of many different earth sciences. Others are glaciology, the study of icy glaciers; seismology, the study of earthquakes; and gravimetry, the study of the earth's gravity. The ocean occupies a large portion of our planet so oceanography also is an earth science. The enfolding atmosphere also belongs to the earth and meteorology, the study of weather, is rated as an earth science.

The word physics is the study of matter and energy. Our large and complicated earth has a lot of separate parts to study. And goodness knows, all the parts give and take a great deal of assorted energies to hold together and work together. This is physics, matter and energy, on a grand scale. Experts took this into account when they needed one group word to include all the earth sciences. The decided on geo¬physics, meaning earth matter energy    and this word seems to do its job very nicely.