Earthquakes
In a few seconds the ground can lurch, crack, and topple buildings. That violent shaking begins with energy stored quietly in rock, sometimes for hundreds of years.
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
Solid Ground, Then Sudden Shaking
The ground beneath your feet feels permanent and still. Yet on May 22, 1960, near Valdivia, Chile, the strongest earthquake ever recorded shook the land so hard that it sent a tsunami racing across the entire Pacific Ocean.
Energy Released in Seconds
That 1960 quake measured magnitude 9.5. Waves it sent across the ocean reached Hawaii, Japan, the Philippines, and the West Coast of the United States. All of that energy was released in a matter of seconds. But where does that much energy come from, and why does it let go so suddenly?
The best answer is B. Rock is not as rigid as it looks. Slowly moving plates push and pull on it, bending it and storing energy inside, sometimes for hundreds of years. When the rock finally cannot bend any more, it fractures and releases that energy all at once. That sudden release is an earthquake. This lesson follows that energy from the moment it builds to the instant it reaches the surface.
- Anchor the lesson in a real, dramatic earthquake.
- Raise a question students will want answered.
- Curiosity gap
- Phenomenon-based learning
- Understand
- DOK 2
- Concrete, familiar example
- Short framing text
- Visual anchor
How Rock Stores and Releases Energy
An earthquake is the release of energy that has built up over time. To understand the shaking, we first have to understand how rock can hold that energy in the first place.
Think about slowly bending a wooden stick. At first it bends and holds its bent shape, storing energy. Push a little more and it suddenly snaps, and both halves spring back straight. Rock in Earth's crust behaves in a similar way.
Moving plates put stress on the rock, a force that pushes, pulls, or squeezes it. The rock bends and stores energy. When the stress becomes too great, the rock fractures.
Stress is a force that pushes, pulls, or squeezes rock. As plates move, they place stress on the rock along their edges. That stress slowly bends the rock and stores energy inside it.
When stressed rock finally fractures, it releases its stored energy and snaps back toward its original shape. This snap-back is called elastic rebound. The released energy travels outward through the ground, and that traveling energy is what shakes the surface.
- Establish the energy mechanism before naming parts of a quake.
- Ground the whole lesson in one cause: stored stress.
- Prior knowledge activation (bending a stick)
- Cause-and-effect modeling
- Understand to Apply
- DOK 2
- Everyday analogy (snapping a stick)
- Short paragraphs with key terms defined in place
Where an Earthquake Begins
Energy is released at one point deep underground, but the shaking is felt at the surface. Two terms tell us exactly where each part happens.
The focus is the point inside Earth where an earthquake begins. It is where the rock first fractures and the stored energy is released.
The epicenter is the point on Earth's surface directly above the focus. It is usually where shaking is felt the strongest, because it is the closest point on the surface to where the energy started.
- Give precise vocabulary for where a quake starts.
- Separate the underground start from the surface effect.
- Dual coding with a labeled cross-section
- Contrast pairs (focus vs epicenter)
- Remember to Understand
- DOK 1 to 2
- Diagram paired with text
- Memory hook for the two terms
- Short, parallel definitions
Where the Rock Breaks
Earthquakes do not happen just anywhere. They happen along faults, and faults tend to cluster in fault zones, most of them at the edges of Earth's plates.
A fault is a crack in Earth's crust where blocks of rock move past each other. When rock fractures and rebounds, it usually happens along a fault.
A fault zone is a region where many faults form. Most fault zones lie at plate boundaries, where the stress from moving plates is strongest. Some earthquakes also occur at ancient fault lines buried deep in newer rock layers.
- Locate earthquakes at faults and plate boundaries.
- Connect plate motion to the type of fault produced.
- Comparison and contrast (three fault types)
- Dual coding with motion diagrams
- Elaboration on prior plate-tectonics learning
- Understand to Analyze
- DOK 2
- Side-by-side cards with diagrams
- Boundary type labeled on each card
- Short, parallel descriptions
The Energy Travels as Waves
Once the rock rebounds, the released energy does not stay put. It travels outward through Earth as seismic waves. Two main types move at different speeds and through different materials.
Seismic waves are waves of energy that travel out from an earthquake through Earth. They spread from the focus in every direction, like ripples from a stone dropped in a pond, only in three dimensions.
Not all seismic waves are the same. The two we focus on here are P waves and S waves.
- The fastest seismic wave, so they arrive first
- Travel through solids, liquids, and gases
- Push and pull the ground back and forth
- Slower than P waves, so they arrive second
- Travel through solids only
- Shake the ground up and down and side to side
Seismic waves do more than shake the ground. Scientists use them to figure out the structure of Earth's interior, a place no one can dig down to reach.
Because S waves cannot pass through liquids, they stop at Earth's liquid outer core. By tracking which waves arrive where, scientists discovered that the outer core must be liquid. The waves act like an X-ray of the planet.
- Explain how the released energy reaches the surface.
- Show seismic waves as evidence about Earth's interior.
- Comparison and contrast (P vs S waves)
- Evidence-based reasoning (waves reveal structure)
- Understand to Analyze
- DOK 2 to 3
- Familiar analogy (ripples in a pond)
- Two short comparison cards
- Parallel bullet structure
How We Measure a Quake
When an earthquake hits, two different questions get asked: how strong was it, and how much damage did it do? Those are measured in two different ways.
On May 22, 1960, an earthquake struck near Valdivia, Chile. At magnitude 9.5, it is the strongest earthquake ever recorded.
Its energy was so great that it sent a tsunami across the Pacific Ocean. The waves reached Hawaii, Japan, the Philippines, and the West Coast of the United States. One earthquake on one coast changed lives on the far side of the world.
- Distinguish how strong a quake is from how much harm it does.
- Close the loop on the opening Valdivia phenomenon.
- Misconception checking (magnitude vs intensity)
- Concrete case study for transfer
- Understand to Analyze
- DOK 2
- Two clearly separated measures
- Plain contrast language
- Memorable real example
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
From Stored Energy to Shaking Ground
You started with a question: how can energy stored in rock make the ground shake? 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 elastic rebound to magnitude and intensity. 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 energy stored in rock ends up shaking the ground at the surface. Name the steps in order, not just the parts. Use the words elastic rebound.
- 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 stored stress to surface shaking in order
- Self-check reveal for comparison, ungraded
- Analyze to Evaluate
- DOK 3
- Sentence-length response, not an essay
- Keyword scaffold ("elastic rebound")
- 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 elastic rebound, the faults that snap and slip, and the seismic waves that carry the shaking outward. 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
Earthquakes are both a clue and a consequence. These lessons show what causes the shaking and what it reveals.