Overview
This lecture covers healthy screen habits, key Earth science terms, and the fundamentals of plate tectonics, focusing on the distribution of volcanoes, earthquake epicenters, and mountain ranges.
Healthy Habits During Screen Time
- Sit with your back supported against the chair.
- Change your position regularly if sitting for long periods.
- Use dim lighting in the room to protect your eyes.
- Get up and stretch during breaks.
- Avoid watching TV in bed to prevent neck and back pain.
Introduction to Plate Tectonics
- Plate tectonics explains Earth’s surface features and movements, both past and present.
- The lithosphere (crust + upper solid mantle) is broken into plates.
- The asthenosphere, below the lithosphere, is solid but softer due to heat and pressure, allowing plate movement.
Key Earth Science Concepts (Mystery Word Challenge)
- The epicenter is the point on Earth's surface directly above an earthquake's focus.
- A mountain is a landmass higher than a hill and projects above its surroundings.
- A seismograph is an instrument to detect and record earthquake vibrations.
- An earthquake is shaking of the Earth caused by volcanic or tectonic activity.
- A volcano is an opening in the crust where lava, ash, and gases erupt.
Distribution of Earthquakes, Volcanoes, and Mountains
- Earthquakes are concentrated in narrow zones, often near plate boundaries.
- Active volcanoes are mostly found along continental edges, especially around the Pacific.
- Major mountain ranges like the Himalayas, Cordilleras, and Sierra Madre are located along plate boundaries.
Plate Movements and Geologic Activity
- Plates move constantly, causing earthquakes, volcanoes, and mountain formation at their boundaries.
- Earthquakes can occur on land or underwater (tsunamis).
- The Pacific Ring of Fire, or Circum-Pacific Belt, is a zone with frequent earthquakes and many active volcanoes, accounting for about 90% of global earthquakes.
Notable Features and Case Studies
- Mount Pinatubo in the Philippines erupted violently in 1991.
- Mount Fuji (Japan) and Mount St. Helens (USA) are significant active volcanoes.
- The Sierra Madre is the Philippines’ longest mountain range, providing natural protection against typhoons.
Key Terms & Definitions
- Plate Tectonics — theory that Earth's outer shell is divided into moving plates.
- Lithosphere — Earth's 100 km thick rigid outer layer (crust + upper mantle).
- Asthenosphere — softer upper mantle below the lithosphere that enables plate movement.
- Epicenter — surface point above the earthquake's focus.
- Seismograph — device measuring earthquake vibrations.
- Ring of Fire — area around the Pacific Ocean with many volcanoes and earthquakes.
Action Items / Next Steps
- Prepare for the next lesson about geophysical hazards in the Philippines.
- Review your self-learning module and any assigned figures or maps.
- Share what you learned today with classmates or on social media using #WonderLearner.