| A | B |
|---|
| continental drift | theory that continents have moved around over time |
| Pangaea | giant continent that existed 200 million years ago |
| seafloor spreading | magma rising at the mid ocean ridge forms new seafloor and forces the plates apart |
| magnetometer | instrument used to study the earth's magnetic field |
| plate tectonics | earth's upper crust and mantle are broken into plates that move around |
| plate | sections of crust that move on the mantle |
| lithosphere | made of the crust and upper mantle |
| asthenosphere | plastic like layer of mantle below the lithosphere |
| divergent boundary | where the plates pull apart |
| convergent boundary | where the plates are colliding |
| subduction zone | where an ocean plate sinks under a continental plate |
| transform fault | where plates slide past each other |
| convection current | a heating-rising, cooling-sinking force that is also thought to move plates |
