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 We Do Elation" (1995). All tracks written by John Scofield. What We Do What We Do is the second studio album by jazz group The John Scofield Quartet. It was recorded in May 1992 and released the following year on the Blue Note label. Besides John Scofield on guitar, the quartet features saxophonist Joe Lovano, Bill Stewart on drums and Dennis Irwin on bass, replacing Marc Johnson. Irwin and Scofield (both born in 1951) had already recorded together in the mid-1980s with Bennie Wallace on a track for his album "Sweeping Through the City." Irwin would be the bassist on two more