IGCSE Marine Science · Structure of the Earth

Core
Dive

Evidence: S-waves can't pass through the outer core, so it is liquid. P-waves refract at the core, making shadow zones. Lehmann found the inner core in 1936.
Magnetic field: created by the iron core . It shields Earth from the solar wind and guides migrating turtles, whales and fish.
Plates: float on the mantle and are moved by convection currents . Mid-ocean ridges make new sea floor, with mirror-image magnetic stripes.
Numbers: the centre is 6,371 km down, the deepest hole is about 12 km, the core is roughly 4,000–5,500 °C, and the last magnetic reversal was about 780,000 years ago.

Drill from the sea floor to the centre of the Earth, track earthquake waves to see inside the planet, then find out how the liquid iron core shields the oceans and steers the sea turtles.

BEST 00000

Sound on · drag to turn the Earth · keys 1–3 pick answers, Enter goes next

CoreDive

Core
Dive