Caldera
A huge, bowl-shaped crater formed when a volcano's summit collapses inward after a major eruption drains out the magma underneath. Many famous lakes — Crater Lake in Oregon, Lake Taupō in New Zealand — are calderas...
Circuit
A closed loop that lets electricity flow. Every working electrical device has at least one circuit inside — a path for the electricity to leave a power source, do something useful, and return.
Core Drill
A BFOE drill that takes small cylinder-shaped samples out of rock or ice, so the team can read the layers inside without breaking the whole thing apart. Real geologists and glaciologists use the same idea — every...
Crater
A bowl-shaped dip at the top of a volcano, left after an eruption has blown rock and lava outward. Some craters are small enough to stand in. Some are wide enough to hold a lake.
Current
The flow of electricity through a wire. Current is measured in amps. A torch uses a small current; a car's starter motor uses a very large one.