Plate Tectonics

I learned that ages of ocean crust and the thicknesses of ocean-floor sediment increase with distance from an ocean ridge and the three types of convergent boundaries are oceanic-oceanic, oceanic continental and continental-continental.

Oceans

I learned that the underwater mountain chains that form when plates move apart is a mid-ocean ridge and that underwater volcanic cones are seamounts.

Water Cycle

The Water Cycle
Water on Earth is always changing. Its repeating changes make a cycle. As water goes through its cycle, it can be a solid (ice), a liquid (water), or a gas (water vapor). Ice can change to become water or water vapor. Water can change to become ice or water vapor. Water vapor can change to become ice or water.