ICSE Class 11 Geography — Flashcards

A: Geography is the description of the earth. It studies variations in relief, climate, drainage, vegetation, soil, and human activities across different places.

A: Geo means the earth and graphos means to write or describe. Together, geography means writing or describing the earth and everything found on it.

A: Eratosthenes coined the word Geography in 234 B.C. He was a Greek geographer who lived in Alexandria, Egypt, and also accurately measured the earth's circumference.

A: The earth is generally believed to be four to five billion years old. This is the broad accepted range used in the chapter.

A: Modern scientific methods to know the age of the earth have been used for about two centuries. These methods include tidal force, sedimentation, erosion, salinity of the ocean, and radioactivity.

A: By the tidal friction first method, the age of the earth is calculated as 4000 million years, or 4 billion years. The idea is linked to the moon’s changing tidal friction as it moved away from the ear

A: Direct observation reaches only very small depths compared with the Earth's radius of 6,370 km. Robinson Deep in South Africa is about 4 km deep, and the deepest oil drilling hole is about 6 km deep.

A: The sources are grouped into direct sources and indirect sources. Direct sources give limited information from shallow drilling and mining. Indirect sources give more important evidence and include de

A: The average density of the Earth is 5.5. Since surface rocks have lower density, the interior must contain much denser material. This suggests that density increases with depth inside the Earth.