Grade IX Geography: Shaping of the Earth's Surface & Atmosphere and Climate

Vocabulary flashcards covering key terms, landforms, atmospheric concepts, and geological processes from Revision Worksheet No. 2.

Weather

Atmospheric conditions that change from hour to hour or day to day.

Climate

Average atmospheric conditions over 30 years or more.

Insolation

Incoming solar radiation received by the Earth.

Precipitation

Water released from clouds in the form of rain, snow, sleet, or hail.

Upper Course of a River

The initial section of a river characterized by steep V-shaped valleys, waterfalls, and rapids.

Middle Course of a River

The middle section of a river characterized by landforms such as meanders, oxbow lakes, and floodplains.

Lower Course of a River

The lower section of a river characterized by landforms such as fan-shaped alluvial deltas and levees.

River Mouth

The point where a river flows into a sea or lake, characterized by the deposition of sediments.

Transform Boundary

A plate boundary characterised by tectonic plates sliding horizontally past each other without creating or destroying the crust, such as along the San Andreas Fault.

Wind Erosion

A type of erosion that is common in dry and sandy areas.

Glacial Erosion

A type of erosion where moving ice scrapes and carries rocks.

Grand Anicut (Kallanai)

An ancient irrigation dam in Tamil Nadu that represents a historic human adaptation to a river meander running water feature.

Coastal Erosion

The process by which waves, tides, and currents wear away the land along the coast.

Beach

A coastal landform found along the seashore formed by the deposition of sediments and made up of sand, pebbles, or rocks.

Tropopause

A boundary layer that separates the troposphere from the stratosphere, below which all weather phenomena occur.

Stratosphere

The atmospheric layer above the troposphere that is free from clouds and most weather disturbances, providing smoother and safer flights for commercial aeroplanes.

Aurora Borealis

Colourful lights dancing across the night sky near the North Pole in the Northern Hemisphere, produced when charged particles from the Sun interact with gases in the Earth's atmosphere.

Ring of Fire

An area located around the Pacific Ocean where most earthquakes and volcanic eruptions occur along plate boundaries.

Climate Change

Long-term changes in weather patterns such as temperature, rainfall, and wind, caused mainly by human activities that release greenhouse gases into the atmosphere.

Lithosphere

The rigid outer layer of the Earth, approximately $100\,\text{km}$ thick, which contains the crust and floats over the semi-molten asthenosphere.

Lower Mantle (Heat Flow)

The interior layer of the Earth that accounts for the highest individual percentage ($32\%$) of total interior heat flow, transported primarily via convection.

Plunge Pool

A depression formed at the base of a waterfall by the hydraulic action and erosive force of falling water and rock debris.