Viscosity is the resistance to flow (opposite of fluidity). Viscosity depends on primarily on the composition of the magma, and temperature. Higher SiO2 (silica) content magmas have higher viscosity than lower SiO2 content magmas (viscosity increases with increasing SiO2 concentration in the magma). Lower temperature magmas have higher viscosity than higher temperature magmas (viscosity decreases with increasing temperature of the magma).
Google does not specifically recommend either DirectX or OpenGL for Google Earth. You can configure Google Earth to operate in either DirectX or OpenGL rendering modes.If your system crashes or performs poorly in one mode, Google recommends you switch to the other mode.penGL Overview. OpenGL is a platform-neutral, open API for rendering graphic images. Although the API is different, OpenGL provides Google Earth with the same graphics performance enhancements as DirectX. OpenGL was originally developed by Silicon Graphics Incorporated.
Here's answer from answers.com : http://wiki.answers.com/Q/What_is_the_difference_between_DirectX_and_OpenGl_Google_Earth. DirectX is a Windows-only API for your video graphics card and OpenGL is a cross-platform API also supported on Windows.f you computers graphic card has to use you systems memory (RAM) then you would open using DirectX. This is microsofts way of letting you enjoy the 3D effects of many programs. When you first install and run GE for the first time, it should tell you which mode to open in and then set it as your default.