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
We Do What We Want decision to write a heavier and more hardcore album than they had done in the past. Commenting on the band's evolved sound, bassist/vocalist Toby Morrell said, "I don't think we ever thought we'd get as heavy as we are now, but I'm glad we have." Though Shelton was not an active member of Emery during the writing process for "We Do What We Want", he wrote the final track on the standard edition titled "Fix Me," and the song "Crumbling" from the deluxe edition. Regarding the album's lyrical themes, vocalist Toby Morrell stated: In the month of March 2011, an