Weathering and Erosion
Mountains look permanent, yet they are slowly being torn down. The same rock that splits apart can travel hundreds of miles and settle somewhere new.
What You'll Be Able to Do
By the end of this lesson, you will be able to:
- State what students will be able to do.
- Set a clear target before content begins.
- Goal setting
- Advance organizers
- Understand to Analyze
- DOK 1 to 3
- Plain "I can" statements
- Standard code shown for reference
- Short, scannable cards
Words You'll Meet
Choose a card to see what each word means.
- Front-load the terms students will meet.
- Lower the language barrier before reading.
- Pre-teaching vocabulary
- Reduced extraneous load
- Remember to Understand
- DOK 1
- One card open at a time
- Click to reveal, no hover
- Plain, short definitions
The Rock That Did Not Last
A boulder looks like it has been there forever. But solid rock splits, crumbles, and disappears, and the pieces show up somewhere far away.
A Mountain Turns Into Sand
High in the mountains, a crack splits a huge boulder cleanly in two. Far downstream, a river slows and drops a beach of sand. The grains of that sand once belonged to rock just like the boulder. So what breaks solid rock apart, and how do the pieces travel so far from where they started?
The best answer is B. Solid rock does not last forever at the surface. First it is broken down into smaller and smaller pieces. Then moving wind, water, and ice carry those pieces away. Finally they settle in a new place. Three connected processes do this work, and that is exactly where this lesson goes next.
- Anchor the lesson in a real phenomenon: a split boulder and a sandy beach.
- Raise a question students will want answered.
- Curiosity gap
- Phenomenon-based learning
- Understand
- DOK 2
- Concrete, familiar examples
- Short framing text
- Visual anchor
Break It, Move It, Drop It
Reshaping the surface takes three connected steps. Naming them now gives you a map for everything that follows.
Weathering includes the processes at or near Earth's surface that cause rocks and minerals to break down. Weathering does the breaking, but it does not move the pieces anywhere.
Erosion is the process of removing Earth materials from their original site through movement and transport. The small, loose pieces that get carried away are called sediment. Wind, flowing water, the sea, and ice all do this work.
Deposition is the laying down of sediment that was carried by wind, flowing water, the sea, or ice. When the wind dies down or the water slows, it can no longer hold the sediment, so the material settles in a new place.
- Map the three processes before studying any in detail.
- Separate weathering from erosion to prevent a common mix-up.
- Advance organizer
- Misconception checking (weathering vs erosion)
- Dual coding with the staged diagram
- Remember to Understand
- DOK 1 to 2
- Plain three-word summary (break, move, drop)
- Key terms defined in place
- Diagram paired with text
Breaking Without Changing
The first kind of weathering breaks rock into smaller pieces. Click a process to see how it works.
Physical weathering includes the processes that break a rock or mineral into smaller pieces without altering its composition. The pieces are smaller, but they are still made of the same material as before.
- Show concrete examples of physical weathering.
- Reinforce that the composition stays the same.
- Concrete examples
- Dual coding with the interactive figure
- Click to reveal each process
- Understand to Apply
- DOK 1 to 2
- Click to reveal, no hover
- Labeled figure paired with text
- Everyday examples
Breaking by Changing
The second kind of weathering does something physical weathering never does. It changes what the rock is made of.
Chemical weathering includes the processes that change the chemical composition of rocks and minerals. Instead of just making smaller pieces, it turns the original minerals into new substances.
Rainwater can pick up carbon dioxide from the air and become slightly acidic. Water containing this acid will break down minerals in a rock, leaving cavities behind.
Over long times in underground caves, this process can build dramatic features. As mineral-rich water drips, it can form stalactites that hang from the ceiling and stalagmites that grow up from the floor.
Minerals may combine with oxygen to form new minerals that are not as hard. You see this when iron rusts and turns a reddish color.
This matters because the new, softer minerals are then worn away more easily by physical weathering. Chemical weathering and physical weathering often work together.
- Contrast chemical weathering with physical weathering.
- Show that the two types often work together.
- Comparison and contrast (size vs substance)
- Concrete examples (rust, cave formations)
- Elaboration linking the two weathering types
- Understand to Analyze
- DOK 2
- Two short cards, one per process
- Familiar example of rusting
- Clear size-versus-substance contrast
Moving the Pieces
Weathering makes the pieces. Erosion and deposition decide where they go. Together they move Earth materials across the planet.
Once rock is broken into sediment, it can be picked up and moved. Erosion is powered by four main carriers:
- Flowing water, like rivers and streams, carries the most sediment of all.
- Wind lifts and blows small, light pieces such as sand and dust.
- Ice, in the form of glaciers, drags rock as it slowly moves.
- Gravity pulls larger rock sections downhill in landslides and rockfalls.
A carrier can only hold sediment while it has enough energy. When a river slows, when the wind dies down, or when ice melts, the material it was carrying settles out.
This laying down of sediment is deposition. It builds new landforms like sandbars, deltas, and beaches, often far from where the rock first broke loose.
- Connect breaking down rock to moving and dropping it.
- Link erosion and deposition through the carrier's energy.
- Cause-and-effect modeling (energy to motion)
- Dual coding with the river diagram
- Elaboration tying the three processes together
- Understand to Analyze
- DOK 2 to 3
- Short bulleted list of carriers
- Labeled diagram paired with text
- Plain cause-and-effect language
Brain Check
Three quick questions before we put it all together. These are not graded. Pulling answers from memory now will help them stick.
- Strengthen memory through retrieval before the wrap-up.
- Surface misconceptions early.
- Retrieval practice
- Generation effect
- Productive struggle
- Understand to Apply
- DOK 1 to 2
- Ungraded and low stakes
- Immediate feedback
- Short tasks reduce load
Break It, Move It, Drop It
You started with a question: how can a boulder in the mountains become sand on a distant beach? Now you can trace the whole chain, step by step.
- Tie the pieces into one cause-and-effect chain.
- Answer the opening question directly.
- Schema building
- Elaboration
- Coherent narrative
- Understand to Analyze
- DOK 3
- Step-by-step beats
- Plain causal language
- Builds on prior sections
Check Your Understanding
Ten questions covering everything you explored, from weathering to deposition. Answer every question, then submit.
Scientists don't just know the answer. They explain their thinking.
Write your own explanation first. Then submit your work to compare your thinking with a model answer.
In one or two sentences, trace how a solid boulder in the mountains can end up as grains of sand on a beach far away. Name the steps in order, not just the parts. Use the words weathering, erosion, and deposition.
- End the lesson with the student building the causal chain in their own words, not selecting it.
- Give the one place where the student generates rather than clicks.
- Generation effect and self-explanation
- Cause and effect: tracing weathering to erosion to deposition in order
- Self-check reveal for comparison, ungraded
- Analyze to Evaluate
- DOK 3
- Sentence-length response, not an essay
- Keyword scaffold (weathering, erosion, deposition)
- Model answer to compare against
- Check understanding against the lesson goals.
- Give students and teachers a clear signal.
- Retrieval practice
- Feedback loops
- Understand to Apply
- DOK 1 to 2
- Answer explanations provided
- Practice and classroom modes
- Plausible, evenly placed options
More Learning
The lesson is just the beginning. Dig deeper into physical weathering, chemical weathering, and the ways wind, water, ice, and gravity move rock across Earth's surface. More investigations, simulations, and challenges are coming soon.
- Offer pathways beyond the core lesson.
- Signal that learning continues past the quiz.
- Interest-driven extension
- Transfer to new contexts
- Apply to Analyze
- DOK 2 to 3
- Optional and self-paced
- Clear labels for what is available
- No penalty for skipping
Connections
Tectonic forces build the land up. These lessons show what wears it back down and reshapes it.