| A | B |
|---|
| direct evidence | rock samples |
| indirect evidence | seismic waves |
| seismic wave | speed and path reveals the structure of the Earth |
| cool to hot | temperature towards the center of the Earth |
| low to high | pressure towards the center of the Earth |
| crust | forms the outer skin of the Earth |
| mantle | lithosphere, asthenosphere, lower |
| lithosphere | crust and uppermost part of the mantle |
| asthenosphere | softer than the lithosphere |
| lower mantle | extends down to the core |
| core | outer and inner |
| outer core | liquid layer surrounding the center of the Earth |
| inner core | solid center of the Earth |
| magnetic field | possibly caused by the outer core |
