Erosion
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40 free Erosion trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Erosion never stops. Rain, rivers, waves, wind and ice are always loosening rock and soil, carrying it off and setting it down somewhere else, and the results range from famous canyons and sea cliffs to the mud in a farm ditch. It is slow enough to ignore from day to day and powerful enough to wear down mountains, which is why it sits near the start of every earth science course. This quiz covers the whole chain. Weathering questions deal with how rock is broken up or dissolved where it stands. Erosion questions follow the pieces as water, wind and ice move them, and deposition questions look at the landforms built where they come to rest. A good share of the page is about soil erosion and its effects: what happens when farmland is left bare, the worst episode of it in American history, and the methods farmers and engineers use to keep soil in place. The early questions suit children and classes meeting weathering and erosion for the first time, and the later ones reach terms a geology student would know. Every answer comes with a short explanation, so the page works for revision as well as for fun.
30 of 40 questions with answers and explanations. Play the quiz
Q 01Which river carved Arizona's Grand Canyon, cutting through a mile of rock in five to six million years?
Colorado
The Colorado did not work alone: side streams and collapsing cliffs widened the canyon to as much as 18 miles across.
Q 02What name was given to the 1930s disaster in which wind stripped bare topsoil from the American Great Plains?
Dust Bowl
Dust Bowl was coined by an Associated Press editor after the Black Sunday storms of April 1935, and the damage reached about 100 million acres.
Q 03Which famous waterfall has retreated almost seven miles upstream since the last ice age by wearing away its own ledge?
Niagara Falls
Niagara Falls once wore back more than three feet a year; engineering works have slowed that to about one foot.
Q 04Which is missing from the Moon, along with liquid water, so that weather never wears away the Apollo bootprints?
An atmosphere
An atmosphere would bring wind and rain; without one, the Moon's surface is worn only by micrometeorites that slowly soften and round its features.
Q 05Which Chinese waterway picks up so much silt crossing the Loess Plateau that its rising bed causes disastrous floods?
Yellow River
Yellow River water gets its color, and the river its name, from that silt, which settles on the bed and slowly builds natural dams.
Q 06Which John Steinbeck novel follows the Joads, an Oklahoma farm family driven out by 1930s drought and blowing soil?
The Grapes of Wrath
The Grapes of Wrath sends the Joads west to California after failed crops cost them the farm, and it won the Pulitzer Prize for fiction.
Q 07England's White Cliffs of Dover, which shed large slabs into the Channel, are made of which soft white rock?
Chalk
Chalk at Dover is streaked with bands of black flint, and it began as white mud made of the skeletons of tiny algae that settled on a Cretaceous seabed.
Q 08Which force drives landslides, rockfalls and mudflows, the downhill movements geologists group together as mass wasting?
Gravity
Gravity needs no river, wind or ice to carry the load, which is what sets mass wasting apart from every other kind of erosion.
Q 09Which icicle-like formation grows down from a cave ceiling as dripping water leaves behind dissolved minerals?
Stalactite
Stalactite was coined in the 17th century by the Danish physician Ole Worm, who built the word from the Greek for dripping.
Q 10Which hazard, common in central Florida, opens when buried rock dissolves and the ground above suddenly gives way?
Sinkhole
Sinkhole collapses are not limited to Earth: in 2015 the Rosetta probe found similar pits on comet 67P/Churyumov-Gerasimenko.
Q 11Which of the main kinds of weathering changes what a rock is made of, as when acid rain dissolves stone?
Chemical
Chemical weathering is why statues, monuments and ornamental stonework can be badly damaged simply by standing outdoors in the rain.
Q 12Which type of weathering splits rock when water trapped in its cracks swells by about nine percent on cold nights?
Frost wedging
Frost wedging needs the crack to be full of water and to freeze quickly from all sides, so the pressure pushes on the rock instead of escaping.
Q 13Which gas dissolves in ordinary rainwater to make the weak acid that slowly eats away cave-forming rock?
Carbon dioxide
Q 21Which landform, like the one where the Mississippi meets the sea, is built from mud a river drops at its mouth?
Delta
Delta was what the Ionian Greeks called the triangle of silt at the mouth of the Nile, a name Herodotus used fourteen times in his Histories.
Q 22Which crescent lake is left behind when a winding river cuts through the neck of one of its own loops?
Oxbow
Oxbow lakes are called billabongs in Australia, and one is complete once silt plugs both ends of the abandoned loop.
Q 23Which word for a river's looping bend comes from a famously winding river in Asia Minor known to the ancient Greeks?
Meander
Meander comes from the Maiandros, today's Menderes in Turkey; the geographer Strabo wrote that everything winding was named after its course.
Carbon dioxide turns even unpolluted rain into carbonic acid with a pH of about 5.6, acidic enough to dissolve solid rock given time.
Q 14Which rock, built largely from shells and skeletons of sea life, dissolves in rainwater to form most cave systems?
Limestone
Limestone is only slightly soluble, so the work is slow, but where it lies exposed over large regions whole landscapes of caverns develop.
Q 15Which term for a landscape of caves and vanishing streams comes from a rocky plateau near the Italian port of Trieste?
Karst
Karst reached European scholars in 1689, when Johann Weikhard von Valvasor used the word to describe rivers flowing underground at Lake Cerknica.
Q 16Which reaction between iron-bearing minerals, water and the air leaves rock surfaces reddish-brown and crumbly?
Oxidation
Oxidation is the same reaction that rusts a nail, and the iron compounds it leaves in rock include hematite and goethite.
Q 17Which crusty organisms, among the first living things to settle on bare rock, slowly turn the stone into soil?
Lichens
Lichens pry mineral grains loose with rootlike threads and then break the fragments down inside their bodies, a process compared to digestion.
Q 18Which weathering process, peeling rock away in curved sheets like onion layers, rounded the granite domes of Yosemite?
Exfoliation
Exfoliation starts with relief from pressure: once erosion strips away the rock above, long-buried granite cracks in shells parallel to its surface.
Q 19Which hard mineral, slow to break down, makes up most of the sand on beaches outside the tropics?
Quartz
Quartz outlasts its neighbors: in granite the feldspar dissolves faster, so the rock crumbles and the tougher grains are left behind as sand.
Q 20Which fine, sticky material is the main product when the feldspar in granite slowly breaks down in water?
Clay
Clay of one kind, kaolinite, forms in abundance in hot, moist climates, and the name kaolin reached English through French reports on Chinese porcelain making.
Q 24Which cross-section, named for a letter, does a mountain glacier leave when it scours a river valley into a trough?
U-shaped
U-shaped troughs take time: remaking the V-shaped valley a river has cut can occupy a glacier for anywhere from 10,000 to 100,000 years.
Q 25Which long, steep-sided sea inlet, found by the hundred along Norway's coast, fills a valley gouged out by a glacier?
Fjord
Fjord coasts are so crinkled that Norway's shoreline measures about 18,000 miles with its inlets counted and only 1,600 miles without them.
Q 26Which ridge of boulders, gravel and grit marks where a glacier dumped the debris it had been carrying?
Moraine
Moraine reached English from French, which took it from a Savoyard word for a mound of earth; the debris runs from fine rock flour to large boulders.
Q 27Which Swiss–Italian border mountain is the classic pyramid peak, sharpened by glaciers biting in from several sides?
Matterhorn
The Matterhorn has four steep faces cut by glaciers hollowing out basins around it, and four of the seven who first climbed it in 1865 died descending.
Q 28Which landform, common in Death Valley, spreads out where a canyon stream reaches flat ground and drops its gravel?
Alluvial fan
Alluvial fan deposits are not unique to Earth: they have been found in abundance on Mars and on Saturn's moon Titan.
Q 29Which bank builds up naturally beside a river as each flood drops its coarsest sand and gravel first?
Levee
Levee comes from the French for raised, and French settlers in Louisiana began building artificial ones in the 18th century to protect New Orleans.
Q 30Which erosion process works like sandpaper, as grit carried by wind, waves, rivers or ice grinds against solid rock?
Abrasion
Abrasion is at its most patient under a glacier, where rocks picked up by the ice are slowly ground against the bedrock below.