Understanding Earth: Materials, Composition, and Movements

Understanding Materials and Natural Resources

Materials are substances with properties that assist human life. The objects surrounding us are diverse, and their production utilizes a wide variety of materials.

Modern materials originate from raw materials found in nature or through the transformation of these commodities. A raw material is a natural substance, sometimes becoming a finished product after processing. A manufactured product is created with one or more materials, which in turn originate from one or more commodities.

Examples of Raw Materials

• Vegetal: Wood, cotton
• Animal: Wool, silk
• Mineral: Iron, oil

The Earth: Our Planet

Earth is the third planet from the Sun. Seen from space, it appears as a solid blue planet, a color resulting from the surface being mostly covered by water.

Earth is relatively small, with a volume over one million times smaller than the Sun and a mass nine times greater than its satellite, the Moon. Its shape is a geoid, with a diameter of approximately 13,000 kilometers and an average temperature of about 15°C.

Historical Perspective

Early cultures believed the Earth was flat. It was not until the 16th century, when Juan Sebastián Elcano completed the first circumnavigation of the globe, that the Earth's round shape was proven.

Layers of the Earth

• Geosphere: The solid part of the Earth, including the surface of continents and the ocean floor.
• Atmosphere: The gaseous layer surrounding the geosphere and hydrosphere.
• Biosphere: The set of all living beings on our planet.
• Hydrosphere: The water layer partially covering the geosphere.

Planetary Movements and Seasons

Rotation: The Earth rotates on an imaginary axis from the North Pole to the South Pole, tilted relative to the orbital plane. This movement from west to east creates the day-night cycle, lasting 24 hours.

Orbit: The Earth completes a full turn around the Sun in one year. The seasons are defined as follows:

• Spring: Starts March 21
• Summer: Starts June 21
• Autumn: Starts September 21
• Winter: Starts December 21

The Moon

The Moon is the closest celestial body to our planet, located about 384,000 kilometers away. Its surface is formed by rock with almost no air. The Moon is characterized by seas, mountains, and craters. Both its rotational and translational movements take approximately 28 days, causing its position relative to the Sun and Earth to vary.