Earth, Life and Science 1st Semester

Earth’s Magnetic Field

A strong field generated by Earth’s nickel-iron core and rapid rotation that shields the planet from solar wind.

Ozone Layer

A stratospheric layer of special oxygen (O₃) that absorbs most of the Sun’s harmful ultraviolet radiation.

Abiogenesis (Biopoiesis)

The natural process by which life arose from non-living organic compounds in Earth’s early oceans.

Tidal Locking

A condition in which an orbiting body (the Moon) rotates at the same rate that it orbits its partner, always showing the same face.

Tides

Regular rises and falls of sea level on Earth caused by the gravitational interaction between Earth and the Moon.

Geological Activity

Processes such as plate tectonics and erosion that continually reshape Earth’s surface, erasing many impact craters.

Axial Tilt (23.4°)

The angle between Earth’s rotational axis and the perpendicular to its orbital plane, responsible for the changing seasons.

Circular Orbit

Earth’s nearly round path around the Sun, contributing to relatively stable seasonal energy input.

Goldilocks Zone (Habitable Zone)

The region around a star where a planet receives just enough energy for liquid water to exist—neither too hot nor too cold.

Liquid Water

The state of H₂O essential for sustaining life; maintained on Earth by suitable temperature and atmospheric conditions.

Habitability Requirements

(1) A long-lived star and (2) a planetary location where water can remain liquid.

Dynamic Planet

A description of Earth’s active interior and surface processes that support and sustain life.

Mercury

Innermost planet; very thin atmosphere, extreme temperatures, slow 59-day rotation, 88-day orbit.

Venus

Second planet; thick CO₂ atmosphere from intense volcanism, very hot, retrograde 243-day rotation, 225-day orbit.

Mars

Fourth planet; thin CO₂ atmosphere, little volcanic activity, cold surface, 24.6-hour rotation, 687-day orbit.

Gas Giants (Jupiter, Saturn, Uranus, Neptune)

Outer planets so far from the Sun that they receive minimal solar energy, resulting in very cold environments.

Origin of Earth’s Water

Initially trapped inside the planet and later released to the surface through volcanic activity.

Mount Everest

Earth’s highest point above sea level, located in the Himalayas.

Challenger Deep

The deepest known point in Earth’s oceans, about 10.9 km below sea level in the Mariana Trench.

Leap Year

An extra day added every four years because Earth’s orbital period is about 365¼ days.

System

A set of interconnected components that interact to form a unified whole.

Earth System

The collective interaction of Earth’s spheres (geosphere, hydrosphere, atmosphere, biosphere) powered mainly by solar energy.

Solar Energy

Radiation from the Sun that drives most processes within the Earth System.

Geosphere

The solid portion of Earth, extending from the surface to the center (~6,400 km deep).

Crust

Earth’s outermost solid layer, about 0–75 km thick.

Mantle

A ~2,900 km thick layer beneath the crust, composed of solid and partially molten rock.

Lithosphere

Rigid layer comprising the crust and the uppermost solid mantle.

Asthenosphere

Partially molten, mechanically weak layer beneath the lithosphere that allows plate motion.

Outer Core

Liquid metallic layer between ~2,900 km and 5,100 km depth.

Inner Core

Solid metallic center of Earth, beginning at ~5,100 km depth and extending to ~6,378 km.

Biosphere

The biological component of Earth containing all living organisms and their environments (biomes).

Anthroposphere

Portion of Earth that has been modified or built by humans.

Hydrosphere

The collective mass of Earth’s water in solid, liquid, and gaseous states.

Cryosphere

The frozen part of the hydrosphere, including ice caps and glaciers.

Freshwater

Only 3 % of Earth’s total water; includes ice caps, groundwater, lakes, rivers, and accessible surface water.

Saltwater

Makes up about 97 % of Earth’s water, primarily in oceans.

Atmosphere

Thin, life-supporting gaseous envelope surrounding Earth, composed of major and variable gases.

Troposphere

Lowest atmospheric layer where weather occurs; temperature decreases with altitude.

Stratosphere

Layer above the troposphere; contains the ozone layer, so temperature increases with altitude.

Mesosphere

Atmospheric layer above the stratosphere; coldest temperatures in the atmosphere occur here.

Thermosphere

Layer from ~85 km up to ~690 km; absorbs high-energy radiation, causing temperatures to rise with altitude.

Exosphere

Outermost atmospheric layer (to ~10,000 km) with very few molecules escaping into space.

System Interaction (Volcanic Example)

A volcano (geosphere) emits ash/gases into the atmosphere, and lava/ash affect surrounding biosphere and hydrosphere areas.

Minerals

naturally occurring inorganic solid that has both a regular crystal structure and definite composition, basically building blocks of rocks

OPTICAL PROPERTIES

Luster

Color

Streak

MINERAL STRENGTH

TENACITY

HARDNESS

CLEAVAGE

FRACTURE

Luster

the quality of light that is being reflected by the surface of a mineral

like: Transparent, Translucent, Opaque

Color

the property of the mineral that is easiest to identify most obvious feature

Streak

the color of mineral in its powdered form can be obtained by rubbing the mineral across a streak plate

Tenacity

level of resistance or action to stress such as crushing,bending, breaking or otherwise being deformed these minerals can either be brittle, malleable and elastic

Hardness

it is a measure of the resistance of a mineral to abrasion or scratching. to determine the hardness of a minerals, the Mohs hardness scale is used Friedrich Mohs

Cleavage

it is the property of some minerals to break along a parallel repetitive planes of weakness to form smooth flat surfaces. smooth flat, pattern surface

Fracture

minerals that breaks at random with rough or jagged edges, the way a mineral breaks when it doesn't break along cleavage planes. rough, jagged, uneven edges.