Geography Made Easy: A Complete Term 2 Revision for Grade 7

🌍 Structure of the Earth

• Crust – Thin, outer layer where we live.
• Mantle – Hot, thick layer below the crust.
• Outer core – Liquid layer of metals (iron & nickel).
• Inner core – Solid, very hot center of the Earth.

🌎 How the Crust Moves

• The Earth's crust is made of large plates (tectonic plates).
• These plates float on the hot mantle and move slowly.
• Movement is caused by heat and pressure from below (convection currents).
• When plates move, they can collide, pull apart, or slide past each other.

🌋 Volcanoes

• Form when magma (hot, melted rock) rises from deep underground.
• Magma erupts as lava, ash, and gases through a volcano.
• After an eruption, lava cools and forms igneous rock.
• Can create new land or mountains (e.g., volcanic islands).

🌊 Floods

• Happen when heavy rain causes rivers or dams to overflow.
• Can damage homes, roads, and crops.
• Common in low-lying areas or places with poor drainage.
• Reduce impact: build on high ground, plant trees, improve drainage systems.

🌐 Earthquakes

• Caused by sudden movement of Earth’s plates.
• Shakes the ground, can break buildings and roads.
• Measured with a seismograph using the Richter Scale.
• Reduce impact: build stronger buildings, have emergency plans.

🔁 Link Between Topics (How They Connect)

• Moving plates cause earthquakes, volcanoes, and sometimes tsunamis.
• Volcanoes form at plate boundaries or over hot spots.
• Floods are not linked to tectonic activity but are part of weather and water cycle.

📏 How We Measure

• Earthquakes – Seismograph + Richter Scale
• Floods – Rain gauge, flood gauge, satellite images
• Volcanoes – Monitored using thermal cameras, gas sensors, and seismographs

🧠 Exam Tips for Learners

• Learn definitions (e.g., magma, crust, mantle).
• Practice labelling diagrams (structure of Earth, volcano, etc.).
• Know real examples (e.g., Paarl Rock = Batholith, KZN = flood-prone area).
• Understand causes and effects clearly.
• Use acronyms or keywords to remember stages (e.g., C-M-O-I = Crust, Mantle, Outer, Inner).