what is the shape of the earth?
oblate spheroid
what is the mean diameter of the earth?
13,000km
recall the layers of the earth as well as details
atmosphere - nitrogen and oxygen
crust - very thin (relatively) - 30km, solid - low density rock
mantle - ≈80% of earth’s volume, lower; solid/upper; semi-molten
outer core - liquid iron and nickel
inner core - solid iron
why is the crust split into tectonic plates?
the two states o9f matter within the mantle allow thermal convection currents to rise and fall, driving the sideways motions of the tectonic plates