Earth Science 30

Earth science supports many occupations - geologist, hydrogeologist, geophysicist, mining engineer, environmental consultant - each with its own roles and educational requirements.

Professional bodies such as the Association of Professional Engineers and Geoscientists of Saskatchewan (APEGS) regulate who may practise, and some fields face shortages while others are oversubscribed.

A strong earth-science investigation begins with a narrow, testable question and a hypothesis predicting a measurable outcome.

The design names variables, methods (field, lab, or modelling), data sources, and safety considerations before collecting data.

Carrying out the study means following the plan, recording data carefully (including from any field experience), and repeating trials where possible.

Analysis turns raw data into meaning through tables, graphs, or maps that let you judge whether the hypothesis was supported.

A portfolio gathers the question, method, data, analysis, and conclusion into a clear story others can follow.

Earth is studied as four interacting spheres: atmosphere (air), hydrosphere (water), biosphere (life), and lithosphere (rock).

Plate tectonics is the unifying theory of earth science: rigid plates move over a hot interior, driven by convection and related forces.

The geologic time scale (eons, eras, periods, epochs) organizes Earth's history and is based on scientists' interpretation of the fossil record.

Earth scientists examine interactions between two or more spheres because most earth processes cross their boundaries.

It subsumes continental drift, supported by matching fossils, minerals, ancient climates, and continental shapes, and explains the assembly and break-up of supercontinents like Pangea.

A mineral is a naturally occurring, inorganic solid with a definite composition and crystal structure, formed by precipitation, crystallization, or biological processes.

The location of resources like potash, uranium, and oil is controlled by depositional setting and geologic history.

Landforms such as moraines, drumlins, coulees, buttes, dunes, and oxbow lakes are the products of deposition, weathering, erosion, and mass wasting.

Geologists identify minerals by standard physical properties: cleavage, fracture, hardness, lustre, colour, streak, and magnetism.

Geologists locate them using imaging methods (satellite, gravity, magnetics, seismic) and seismic body waves - longitudinal p-waves and transverse s-waves - obeying the laws of reflection and refraction.

The atmosphere is mostly nitrogen and oxygen with trace gases; its oxygen came largely from ancient photosynthetic life.

The hydrosphere is distributed among groundwater, surface water, oceans, glaciers, and the atmosphere.

Notable events - the Great Oxygenation Event, Snowball Earth, volcanic activity, asteroid impacts - changed atmospheric composition over Earth's history, inferred from ice, tree rings, and sediments.

Porosity and permeability control how groundwater is stored and flows, and groundwater can erode rock to form Karst features like sinkholes and caverns.

Technologies like satellites, weather balloons, and radiosondes gather atmospheric data used to study weather and climate.