Structure of the Earth easily than does the upper mantle (chemical changes within the mantle may also be important). The viscosity of the mantle ranges between 10 and 10 Pa·s, depending on depth. In comparison, the viscosity of water is approximately 10 Pa·s and that of pitch is 10 Pa·s. The source of heat that drives plate tectonics is the primordial heat left over from the planet’s formation as well as the radioactive decay of uranium, thorium, and potassium in Earth’s crust and mantle. The average density of Earth is . Because the average density of surface material is only around , we must
What Would We Do Without You? Do Without You?" is a song taken from the Stephen Sondheim musical, "Company". What Would We Do Without You? "What Would We Do Without You?" is the 69th episode of the ABC television series "Desperate Housewives". It was also the twenty-second episode of the show's third season. It was written by Bob Daily and directed by Larry Shaw. The episode aired on May 13, 2007. Ricardo Antonio Chavira submitted this episode for consideration on his behalf in the category of "Outstanding Supporting Actor in a Comedy Series" at the 2007 Emmy Awards. Mike and Susan go out to dinner, the