The tests used to determine whether brain stem death has occurred are outlined below: 1  A torch is shone into both eyes to see if they react to the light. 2  The cornea (transparent outer layer of the eye), which is usually very sensitive, is stroked with a tissue or piece of cotton wool to see if the eye reacts.
The inner core extends another 900 miles inward towards the center of the Earth. It is believed that this inner core is a solid ball of mostly iron, and nickel. The mantle is made of much denser, thicker material, because of this the plates float on it like oil floats on water.
The Earth has an inner core and an outer core. Scientists think that the inner core is solid and mainly made of iron. Iron is very hard â thatâs why knights used it to make their armour. The outer core is also mostly iron, but this layer is liquid (melted) iron.he crust is the part of the Earth that we walk on. Compared to the other layers, it is quite thin and breakable. You can think of the crust of the Earth as being a bit like the crust of a pie â although this crust is 5â70 km deep depending on whether you are under the ocean or on top of a mountain!