Ch 1 Earth as a planet

What is the shape of the Earth?

The Earth is shaped like an oblate spheroid. This means it bulges at the equator and is flattened at the poles.

Give nine proofs that the Earth is spherical.

Proofs that the Earth is spherical include: ships disappearing hull first over the horizon, the Bedford Level experiment, the position of the pole star, satellite imagery, lunar eclipses, the circular horizon, different sunrise and sunset times, circumnavigation, and observing Earth as a heavenly body.

What are the Earth's diameters at the equator and poles?

The Earth's diameter at the equator is 12,756 kilometers. At the poles, it is 12,714 kilometers.

Explain why Earth is a suitable home for humankind.

Earth is a suitable home because it has green vegetation, vast oceans, islands, continents, streams, and rivers.

Why is Earth suitable for humans?

Earth is suitable for humans because of its distance from the sun, moderate temperature, atmosphere, and water.

What is the average temperature of Earth?

The average temperature of Earth is 17°C. This temperature supports life; even small changes could harm species.

What is the atmosphere?

The atmosphere is the layer of gases around Earth. It is a mixture of nitrogen, oxygen, carbon dioxide, argon, etc. It receives heat from the sun and helps keep Earth warm.

Define biosphere.

The biosphere is the network of all interconnected ecosystems.

Define ecosystem.

An ecosystem is a self-regulating and self-sustaining unit of the biosphere.

What is the life zone of the earth?

The biosphere is the part of Earth's system where life develops and transforms. It includes air, land, and water.

Water cycle is also known as?

The water cycle is also known as the hydrological cycle.

What is lithosphere?

The lithosphere is the solid crust of the Earth.

What is the extent of biosphere?

The biosphere extends up to 15 km.

Define biosphere.

The biosphere is the area where the atmosphere, hydrosphere, and lithosphere meet.

Define greenhouse effect.

The greenhouse effect is the trapping of the sun's radiation by gases in the lower atmosphere.

Explain Bedford level experiment.

In the Bedford Level experiment, three poles were placed 5 km apart. The middle pole appeared slightly higher when viewed from a distance.

When and where did Magellan’s ship Victoria complete the voyage?

Magellan’s ship Victoria completed its voyage around the Earth in 1552 in Spain.

How can you prove the Earth is a sphere by looking at the horizon?

When seen from a height, Earth's surface looks circular. The circular horizon widens with altitude, proving Earth's spherical shape.

What is pole star?

The Earth's axis points to the north celestial pole. The North Star appears stationary as the earth rotates.

Explain sighting of ship as proof of spherical shape of the earth.

When a ship approaches, you see its mast first, then the deck, and finally the hull. This proves Earth is spherical.

Give reason Venus is hotter than mercury?

Venus is hotter than Mercury because its atmosphere contains carbon dioxide, which causes the greenhouse effect.

Water bodies reduce day and night temp variation. Give reason

Water absorbs heat