Earth Science questions
69 fact-checked questions — tap any to predict the answer, then read why.
- In folded Appalachians, why can one rock layer become a ridge while its neighbor becomes a valley?
- Loose material moves downhill from a fresh fault scarp, rounding it. What sets the smoothing speed?
- Why can a long active fault affect more river basins than a short one?
- Why does erosion happen faster near active faults than in areas with heavy rain?
- Why can quartz sand with beryllium-10 reveal how fast a whole river basin erodes?
- Earthquake shaking lasts seconds. How can it leave rock easier for later rivers to erode?
- Why do rivers near active faults erode faster than rivers far away?
- Two basins have similar rain and rock type; one lies nearer active faults. Why erode faster?
- A large igneous province is a vast lava-and-magma episode. Why can it hurt far oceans?
- CO2 and SO2 can both leave big eruptions. Why do their climate effects split?
- Sills are buried magma sheets. Why can Siberian sills pose more risk than lava?
- A large igneous province is a continent-scale volcanic outburst. Why abrupt extinctions?
- Hawaiian volcanoes get older northwest of the Big Island. What records that?
- A plume head is a broad hot-mantle blob. Why can it make a huge basalt province?
- A mantle plume is hot solid rock, not a lava pipe. How can it make magma?
- Mid-ocean ridges hide Earth’s longest mountain chain. Why so volcanic?
- Mid-ocean ridges erupt more lava every year than all land volcanoes combined. What drives them?
- On the deep seafloor, why do gas bubbles in lava stay small while surface lava bursts into ash?
- How can melting ice make Icelandic volcanism spike instead of calm down?
- What helped Surtsey survive storms while nearby Surtseyan islets vanished?
- Why did wide ash aprons hint that some Reykjanes vents breached the sea surface?
- Reykjanes seafloor cones have flat tops at similar shallow depths. Why?
- Why can a shallow Reykjanes seafloor volcano blast harder than a deep one?
- Why do deep mid-ocean ridges usually ooze lava instead of blasting ash?
- Earth's inner core is roughly as hot as...
- What actually moves Earth's magnetic north pole?
- What keeps the Amazon's thin soil from starving?
- Why did the deepest hole ever drilled stop at 12 km?
- What drives India into Asia beneath Tibet?
- Why do deserts get cold at night?
- Why do mountains have tree lines?
- Why do some beaches have black sand?
- Why does quicksand trap people?
- Why does sandstone have layers?
- Why are fossils usually flat?
- Why do tides happen twice daily?
- Why do some islands sink?
- Why do opals show rainbow colors?
- Why are icebergs freshwater not salty?
- Why do some rocks glow under UV light?
- Why do rivers meander in curves?
- Why do cliffs erode into arches?
- Why do fossils form in sedimentary rock?
- Why is ocean water salty?
- Why do sinkholes suddenly appear?
- Why do minerals form crystals?
- Why do deserts exist near coasts?
- How do valleys form in mountains?
- Why are some rocks magnetic?
- Why do hot springs exist?
- Why does Earth have magnetic poles?
- Why do sand dunes move?
- Why do caves have stalactites?
- Why do geysers erupt regularly?
- Why do glaciers move?
- Why does sand exist at beaches?
- Why are there waves in the ocean?
- Why do mountains have snow on top?
- Why do volcanoes erupt?
- Why does earth have different layers?
- Why is underground water cold?
- Why do rivers flow to the ocean?
- Why do islands form?
- How are caves formed?
- Why do tsunamis happen?
- Why do deserts exist?
- Why are fossils found in rocks?
- Why is the ocean salty?
- Why do earthquakes happen?