Lesson: Earthquakes

Year: 4 | Subject: Geography | Time Allocation: 100%

Class/Set: ____________ Date/Term: ____________

LO (WALT): To describe the causes of earthquakes and examine their physical and social impacts.

Success Criteria (WILF):

1. I can explain how the movement of tectonic plates causes tremors.
2. I can identify how seismic waves are measured using the Richter Scale.
3. I can contrast the physical and social impacts on communities in high-risk zones.

1. Starter (15% - Retrieval and Hook)

• Recall: Distribute mini-whiteboards. Ask students to sketch a diagram of the Earth's layers (Crust, Mantle, Outer Core, Inner Core) from previous learning.
• Hook: Place a glass of water on a central table. Ask a student to jump heavily nearby.
• Discuss: Observe the ripples. Ask: "If this glass was a skyscraper and the jump was the Earth shifting, what would happen?"
• Connect: Explain that today we are investigating what happens when the 'jigsaw pieces' of our Earth’s crust move suddenly.

2. Main Activity (70% - Knowledge and Application)

Teacher Input:

• Explain: The Earth's crust is split into tectonic plates that 'float' on the mantle. These plates are constantly moving, but they don't have smooth edges.
• Model: Use two rough bricks or textured exercise books. Rub them together. Show how they 'snag' and get stuck.
• Script: "Class, imagine these are two tectonic plates. They want to move past each other, but they are caught. Pressure is building up... and building... and... SNAP!" (Suddenly slide them). "That sudden release of energy is the earthquake. The point where it starts underground is the focus; the point directly above on the surface is the epicenter."
• Demonstrate: Show an image of a seismometer. Explain that it works like a pen on a wobbly table. The more the Earth shakes, the bigger the 'zig-zags' (seismic waves) on the paper.
• Define: Introduce the Richter Scale (Magnitude 1–10). Explain that each number is 10 times stronger than the one before.
• Compare: Use a T-chart on the board to define 'Physical Impacts' (e.g., cracked roads, fallen buildings) versus 'Social Impacts' (e.g., families losing homes, schools closing, people feeling scared).

Student Task:

• Task A: The Earthquake MCQ. Students must complete the 'Seismic Knowledge' check below to demonstrate their understanding of causes and measurement.
• Task B: The Magnitude Match. Students use the data table provided to match the Richter Scale magnitude to the correct real-world description.
• Task C: Impact Sorting. Students read a short case study of a high-risk zone (e.g., San Francisco or Tokyo) and categorise four specific impacts as either 'Physical' or 'Social'.
• Support: Provide a 'Word Bank' (Tectonic, Epicenter, Magnitude, Seismic) for Task C.
• Challenge: Ask 'Greater Depth' students to explain why a magnitude 6 earthquake might cause more social impact in a poor country compared to a wealthy country (linking to building quality).

Task A: Seismic Knowledge Check

1. What are the giant pieces of the Earth's crust called?

   • a) ☐ Tectonic plates
   • b) ☐ Mantle blocks
   • c) ☐ Rock slices
   • d) ☐ Crustal crumbs

2. What is the name of the machine used to measure earthquake vibrations?

   • a) ☐ Thermometer
   • b) ☐ Barometer
   • c) ☐ Seismometer
   • d) ☐ Anemometer

Task B: Magnitude Match

Richter Magnitude	Effect on the Land
2.0	Match 1:
5.0	Match 2:
8.0	Match 3:

Task C: Impact Sorting

Instruction: Sort these four impacts from a high-risk zone into the correct column:

1. Hospitals collapse.
2. Families are moved into tents (homelessness).
3. Railway lines are twisted.
4. Children are unable to attend school.

Physical Impact	Social Impact

3. Plenary (15% - Consolidation)

• Review: Use the 'Human Richter Scale'. Ask students to stand. If you say "Magnitude 1", they stand still. If you say "Magnitude 9", they must (safely) vibrate and wobble.
• Check: Ask: "Why is an earthquake in a city more dangerous than an earthquake in the middle of a desert?"
• Consolidate: Reiterate that while we cannot stop earthquakes, communities in 'high-risk zones' use science to measure them and engineering to protect buildings.

4. Resources

• Rough bricks or textured exercise books for modelling.
• Glass of water.
• Earthquake Case Study Handout (Year 4 level).
• T-chart worksheets for Task C.
• Seismograph images/videos.

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⚠ TEACHER’S GUIDANCE

💡 Pedagogical Pulse

• Delivery Advice (Year 4): At this age, the concept of 'plates' is very abstract. Always refer back to the jigsaw puzzle analogy. Ensure you use the term 'tremor' to describe the physical sensation.
• Misconception Alert: Many students believe the Earth 'opens up' into a bottomless pit. Clarify that while cracks (fissures) appear, an earthquake is primarily about the shaking and the collapse of man-made structures.
• Safety & Nuance Check: Be sensitive to students who may have family in regions recently affected by natural disasters. Focus on the 'Preparation' aspect (Earthquake drills, strong buildings) to provide a sense of agency and safety.

✅ Answer Key & Mirror-Labeling

• Task A Answer (Question 1): a) ☐ Tectonic plates.

• Task B Answer (Question 2): c) ☐ Seismometer.

• Task B Answer (Magnitude Match):

  • 2.0: Match 1: Small tremors, usually not felt by people but recorded.
  • 5.0: Match 2: Furniture moves; chunks of plaster might fall from walls.
  • 8.0: Match 3: Total destruction of buildings; bridges snap; ground ripples.

• Task C Answer (Impact Sorting):

  • Physical Impact: 1. Hospitals collapse; 3. Railway lines are twisted.
  • Social Impact: 2. Families are moved into tents; 4. Children are unable to attend school.

• Next Steps: In the following lesson, students will look at 'Earthquake Proofing' and design their own structures using marshmallows and cocktail sticks to test on a 'jelly' earthquake base.