GACE Middle Grades Science Questions & Correct Answers | Latest Updated | Graded A+

tidal hypothesis : Theory that the solar system started with a near collision of sun and large star. Few astronomers believe this theory. condensation hypothesis : solar system began with rotating clouds of dust and gas. Condensation happened in center to form sun, and smaller parts of clouds formed. More astronomers believe in this idea. Core : Outer core- liquid; inner core- solid. Very dense in center. Believed that core is 80% iron. Helps heat oceans. Mantle : Surrounds core. Semi-solid/plastic and the viscosity varies as pressures and temps. change at different depths. Page | 2 Crust : Outermost layer of the Earth. Least dense layer. Sedimentary rocks : forms when sediment collects and hardens; layers of sediment pile up and squeeze together; requires pre