Physical Weathering
What is Physical Weathering?
Physical weathering is the breaking of rocks into smaller pieces without changing what the rock is made of.
What is chemical weathering?
Chemical weathering is when rocks change into new materials because of chemical reactions (the rock's minerals are changed).
What is erosion?
Erosion is the movement of weathered rock and soil from one place to another by wind, water, ice, or gravity.
What is deposition?
Deposition is when eroded materials (sediment) are dropped or settle in a new place.
DAILY DOUBLE!!!
Define "sediment" in one sentence.
Sediment is small pieces of rock, soil, or mineral broken off and moved by weathering and erosion.
Name one example of physical weathering caused by water (not chemical).
Waves crashing and pounding rocks, causing them to break apart; or water wearing away rock surfaces.
Name one chemical change that happens when acid rain affects a rock or statue.
Acid rain can slowly dissolve parts of limestone or marble statues, making surfaces pitted or smooth away.
Name two agents of erosion (two moving things that carry sediment).
Agents: water (rivers), wind, ice (glaciers), gravity (landslides).
DAILY DOUBLE!!!
Where does deposition often happen when a river slows down? (Name a place or landform.)
Deposition often happens in river bends, floodplains, or at the mouth of a river (a delta).
What is a "delta"? (Short definition)
A delta is a landform made of sediment deposited where a river flows into a larger body of water.
DAILY DOUBLE!!!!
How can freezing and thawing break a rock apart? Use the words "water" and "crack" in your answer.
Water enters cracks, freezes, then expands, making the crack bigger until pieces break off.
How does oxidation change some rocks? (Hint: think of iron and rust.)
Oxidation: iron in rocks reacts with oxygen and water to form rust, weakening the rock and changing its color.
How does a fast-moving river change the shape of its banks over time?
Fast-moving rivers pick up sediment and cut into banks, making them erode away and changing the river's shape.
How can deposition build a beach along a coastline?
Waves and currents carry sand and deposit it along the shore, building up a beach.
What does "weathering" mean? How is it different from erosion in one sentence each?
Weathering is the breaking down of rock into smaller pieces; erosion is the movement of those pieces to new places.
Describe how plant roots can cause physical weathering.
Roots grow into cracks and as they get bigger they push the rock apart.
DAILY DOUBLE!!!
Explain how water can cause chemical weathering when it dissolves minerals from rock.
Water can dissolve minerals (like salt or limestone) in rock, carrying those minerals away and leaving holes or weakened rock.
Explain how wind moves sand in a desert to form dunes.
Wind lifts and rolls sand grains; as they strike each other and surfaces, sand moves and piles into dunes.
Explain how a delta forms at the mouth of a river using the words "sediment" and "water slows."
As a river slows when it meets a larger, stiller body of water, it drops sediment it carried and a delta forms from the deposited material.
Define "abrasion" and give one example.
Wind lifts and rolls sand grains; as they strike each other and surfaces, sand moves and piles into dunes.
Explain how abrasion works to wear down rocks. Include what moves and what gets worn down.
Abrasion is when rocks or particles scrape or grind against other rock surfaces (moved by wind, water, or ice), slowly wearing them down.
Describe a way plants or living things can cause chemical weathering (use words like "acid" or "decay" in your answer).
Plant roots and decaying plants can produce weak acids that dissolve minerals in rock; lichens or moss can release chemicals that slowly break down rock.
DAILY DOUBLE!!!
Describe how glaciers erode the land and name one landform they can create.
Glaciers scrape and pluck rocks as they move, carving U-shaped valleys and creating landforms like fjords or moraines.
Describe how deposition can create a sandbar in a river or near a shore.
When the water or wind slows, sand or pebbles settle and pile up to form sandbars.
Use these words correctly in one sentence: "weathering," "erosion," and "deposition."
Here is an example: (Answers will vary!) "Weathering breaks the cliff into loose sediment, erosion carries the sediment downriver, and deposition builds a new sandbar where the river slows."