MS-ESS2-2: Changes in Earth's Surface

MS-ESS2-2
Changes in Earth's Surface

Middle School

​

Learning Objectives

• Explain how processes like weathering and erosion change Earth’s surface over time.

• Differentiate between slow changes and sudden events that shape different landforms.

• Describe how forces can build up and wear down features on Earth.

• Explain how a landform can result from many processes over long periods.

Key Vocabulary

​

Geoscience Process

A geoscience process is any natural force or action that works to shape the Earth's surface over time.

​

Catastrophic Event

A catastrophic event is a sudden and intense natural occurrence that causes rapid, significant changes to the Earth.

​

Weathering

Weathering is the natural process that breaks down rocks, soil, and minerals on the Earth's surface.

​

Erosion

Erosion is the geological process in which Earth materials are worn away and transported by natural forces.

​

Ice Wedging

Ice wedging is a form of physical weathering caused by water freezing and expanding in rock cracks.

​

Chemical Weathering

Chemical weathering describes the breakdown of rocks and minerals as a result of different chemical reactions.

Key Vocabulary

​

Karst Topography

A unique landscape that is formed by the dissolution of soluble rocks like limestone.

​

Differential Erosion

This process occurs when softer rock erodes away, leaving the harder, more resistant rock behind.

​

Geosphere

The geosphere refers to the solid, rocky parts of our planet, including rocks and landforms.

​

Lithosphere

The lithosphere is the rigid outer layer of the Earth, which consists of the crust.

​

Plate Tectonics

This scientific theory describes the large-scale movement of the Earth's seven major lithospheric plates.

​

Subduction

Subduction is the geological process of one tectonic plate moving underneath another tectonic plate.

​

​

Geoscience Processes: A Matter of Scale

Slow Processes

• The movement of continents is a slow process that takes millions to billions of years to happen.

• Plate tectonics gradually shapes oceans and builds massive mountain ranges over very long periods of time.

• Weathering is another slow process where wind and water gradually break down rocks over many years.

Rapid Events

• Some events like earthquakes happen very quickly, often in just a few seconds or minutes.

• A single drop of rain dissolving minerals is a rapid change on a microscopic scale.

• Catastrophic events like landslides can dramatically alter a landscape in just a matter of hours.

Multiple Choice

What is the main characteristic used to classify the geoscience processes described?

• The amount of energy they release

• The time scale over which they occur

• The location where they happen

• The type of landforms they create

Multiple Choice

Which of the following statements correctly compares a slow process with a rapid event?

• The building of mountains is a rapid event, while a landslide is a slow process.

• Weathering from wind and water happens quickly, in just a few hours.

• The movement of continents and earthquakes both take millions of years.

• Plate tectonics gradually builds mountains over millions of years, while an earthquake can happen in seconds.

Multiple Choice

How can the action of water on rock be described as both a slow process and a rapid event?

• It is slow when wind is also involved, but rapid when it is just water.

• It is slow when forming mountains, but rapid when causing earthquakes.

• It is slow when weathering breaks down large rocks over years, but rapid when a single drop dissolves a mineral in seconds.

• It is always a slow process, but it can seem rapid during a catastrophic landslide.

​

​

Types of Physical Weathering

Ice Wedging & Plant Roots

• Water seeps into cracks, freezes, and expands with great force, making the crack wider.

• Repeated cycles of freezing and thawing can eventually split large rocks into jagged pieces.

• Plant roots can also grow into cracks, forcing the rock apart as they expand.

Abrasion

• Physical weathering breaks rocks into smaller pieces without changing what the rock is made of.

• Abrasion occurs when rocks are scraped and smoothed by colliding with other rocks or particles.

• This happens when rocks are tumbled by moving water or are hit by windblown sand.

Multiple Choice

What is the primary outcome of physical weathering?

• Large rocks are broken into smaller pieces.

• The chemical makeup of the rock is changed.

• Rocks are dissolved by acidic water.

• New types of minerals are formed inside the rock.

Multiple Choice

How are the weathering effects of ice wedging and plant roots similar?

• Both processes break rocks by forcing cracks to become wider.

• Both processes smooth the surface of the rock through friction.

• Both processes involve cycles of freezing and thawing.

• Both processes are caused by the action of moving water.

Multiple Choice

A large, jagged rock breaks off a cliff and falls into a fast-flowing river. What will the rock most likely look like after a year?

• It will be smaller and have a smooth, rounded surface.

• It will be larger and covered in ice.

• It will have dissolved completely in the water.

• It will be unchanged from its original jagged shape.

​

​

Chemical Weathering and Karst Landscapes

Chemical Weathering

• ​Chemical weathering breaks down rocks by changing the minerals they are made of.

• ​​Rainwater mixes with carbon dioxide from the air to form a weak acid.

• ​This acid, called carbonic acid, can slowly dissolve microscopic amounts of minerals.

Karst Landscapes

• ​This process is especially effective on a rock called limestone over thousands of years.

• ​​The dissolving of limestone creates unique landforms known as karst topography, like caves and sinkholes.

• ​This type of weathering is most common in humid environments because moisture is required.

Multiple Choice

What is chemical weathering?

• A process that breaks down rocks by changing their mineral composition.

• A process that moves broken rock pieces from one place to another.

• A process that glues sediments together to form a new rock.

• A process that breaks rocks into smaller pieces without changing them.

Multiple Choice

What is the relationship between rainwater and the formation of karst landscapes?

• It physically forces the rock to crack open under pressure.

• It freezes and expands in cracks, breaking the limestone apart.

• It forms a weak acid that slowly dissolves limestone, creating features like caves.

• It washes away the topsoil, exposing the limestone to the sun.

Multiple Choice

In which of these environments would you most likely expect to find a large number of caves and sinkholes forming?

• A tropical rainforest with high levels of rainfall.

• A cold desert with very little precipitation.

• A frozen polar ice cap with no liquid water.

• A dry grassland with infrequent rain showers.

​

​

How Erosion Shapes Landforms

• Erosion is the movement of weathered rock by water, wind, or ice.

• Softer rock erodes faster, leaving harder rock formations behind.

• This process creates dramatic landforms, such as the famous Devils Tower.

• Wind carries Sahara dust to the Amazon, providing essential nutrients.

​

Multiple Choice

What is the definition of erosion?

• The movement of weathered rock by water, wind, or ice.

• The process of rock breaking down into smaller pieces in one place.

• The formation of new landforms by volcanic activity.

• The settling of rock particles in a new location.

Multiple Choice

What is the relationship between rock hardness and the creation of landforms like Devils Tower?

• Softer rock erodes faster, which exposes the harder rock.

• Harder rock erodes faster, which exposes the softer rock.

• All types of rock erode at the same rate, regardless of hardness.

• Erosion only happens to rocks that are near a river or ocean.

Multiple Choice

Considering the different effects of erosion, what is a long-term consequence of wind moving material from a place like the Sahara Desert to the Amazon rainforest?

• The desert loses surface material, while the distant rainforest gains nutrients.

• The rainforest loses soil, while the distant desert gains plant life.

• Both the desert and the rainforest will remain unaffected by the wind.

• The wind will cause the desert to become cooler and the rainforest to become drier.

Rapid and Catastrophic Events

​

Volcanic Eruptions

• ​Volcanoes can create new landforms when their hot lava flows and cools.

• ​​These eruptions can also be incredibly destructive to the surrounding environment.

• ​The landscape can be changed in just a matter of hours.

​

Earthquakes & Landslides

• ​Earthquakes can shake the ground and trigger sudden, massive landslides.

• ​​These events move enormous amounts of rock and soil very quickly.

• ​The shape of a mountainside can be altered in an instant.

​

Meteor Impacts

• ​Meteor impacts are rare but are the most extreme catastrophic events.

• ​​A large impact can create a massive, bowl-shaped crater in seconds.

• ​Over millions of years, erosion slowly changes the crater's appearance.

Multiple Choice

What is a primary characteristic of catastrophic events like volcanic eruptions and earthquakes?

• They cause very fast changes to the Earth's surface.

• They are caused by the slow movement of water and wind.

• They only happen in areas near the Earth's oceans.

• They make the environment safer for plants and animals.

Multiple Choice

How are the effects of volcanic eruptions and meteor impacts similar?

• Both events can result in the formation of new landforms.

• Both events are primarily caused by the movement of rock and soil.

• Both events are described as being incredibly rare.

• Both events trigger immediate and massive landslides.

Multiple Choice

A steep mountain is located in a region that experiences frequent earthquakes. Based on the information about Earth's processes, what is the most likely immediate risk to this mountainside?

• A sudden landslide could quickly alter the shape of the mountainside.

• The mountain will slowly get smaller as erosion occurs over millions of years.

• A large, bowl-shaped crater will form on the mountainside in seconds.

• Hot lava will flow down the mountain and create new landforms.

​

​

Earth's Structure and Plate Tectonics

• Earth's rigid outer layer, the lithosphere, is broken into large plates.

• ​These plates float on the asthenosphere, a weaker part of the mantle.

• Plate tectonics is the slow, gradual movement of these plates over time.

• This movement is a constructive force, creating continents, oceans, and mountains.

​

Multiple Choice

What is the definition of plate tectonics?

• The slow, gradual movement of Earth's plates over time.

• The rigid outer layer of the Earth that is broken into plates.

• The weaker part of the mantle that the plates float on.

• The force that creates continents, oceans, and mountains.

Multiple Choice

What is the relationship between the lithosphere and the asthenosphere?

• The lithosphere is broken into plates that float on the weaker asthenosphere.

• The asthenosphere is broken into plates that float on the rigid lithosphere.

• The lithosphere and the asthenosphere are both parts of the rigid outer layer.

• The asthenosphere is a constructive force that pushes the lithosphere.

Multiple Choice

Based on the information provided, what conclusion can be drawn about the long-term effect of plate movement?

• It is a constructive force that builds major landforms.

• It causes the asthenosphere to become a rigid layer.

• It prevents the formation of new oceans or continents.

• It is a process that only happens in the Earth's core.

​

​

Plate Boundaries and Mountain Building

Volcano Formation

• A dense oceanic plate slides under a continental plate in a process called subduction.

• The subducting plate heats up and melts, forming hot molten rock called magma.

• This magma rises to the surface and erupts, creating volcanoes on the continent.

Mountain Building

• When two continental plates of similar density collide, neither one can easily subduct.

• The immense pressure from the collision causes the Earth's crust to buckle and fold upwards.

• This slow process, known as uplift, builds massive mountain ranges over millions of years.

Multiple Choice

What is subduction?

• The process where a dense oceanic plate slides under a continental plate.

• The process where two continental plates collide and buckle upwards.

• The process of magma rising to the Earth's surface to form mountains.

• The process of two plates slowly sliding past one another over millions of years.

Multiple Choice

What is the primary difference between how volcanoes and mountain ranges are formed at plate boundaries?

• Volcanoes form from subducting plates melting, while mountains form from colliding plates buckling.

• Volcanoes are created by fast-moving plates, while mountains are created by slow-moving plates.

• Volcanoes only form on continents, while mountains only form in the ocean.

• Volcanoes are caused by uplift, while mountains are caused by magma eruptions.

Multiple Choice

Imagine two continental plates of similar density are slowly moving toward each other. What is the most likely geological outcome of this interaction over millions of years?

• A large mountain range will form as the two plates buckle and fold upwards.

• The denser of the two plates will subduct, leading to volcano formation.

• A deep ocean trench will form as the two plates pull apart from each other.

• The plates will slide past each other, causing a major earthquake.

​

Common Misconceptions

Misconception	Correction
Weathering and erosion are the same.	Weathering breaks down rock, while erosion moves the pieces.
Earth’s surface is static.	Earth's surface is dynamic and constantly being reshaped.
Mountains only get smaller.	Tectonic forces build mountains up; some are still growing.
All geological changes are slow.	Catastrophic events can change the surface dramatically and quickly.

​

Summary

• Earth's surface is constantly changing due to various geoscience processes.

• Slow processes like erosion and plate tectonics shape landforms over long periods.

• Rapid events like volcanoes and earthquakes cause sudden, dramatic changes.

• Landforms result from multiple processes that will continue to shape Earth's future.

Poll

On a scale of 1-4, how confident are you about explaining how Earth's surface changes over time?

• 1

• 2

• 3

• 4