🫴Physical Science Unit 15 – Environmental & Applied Physical Science

Key Concepts & Principles

• Physical science studies the natural world and non-living systems through observation, experimentation, and mathematical analysis
• Matter is anything that has mass and takes up space (atoms, molecules, substances)
• Energy is the capacity to do work or cause change and can take many forms (kinetic, potential, thermal, electrical, chemical, nuclear)
  • Law of Conservation of Energy states that energy cannot be created or destroyed, only converted from one form to another
• Interactions between matter and energy drive environmental processes and shape Earth's systems (water cycle, carbon cycle, nutrient cycles)
• Earth is a complex, dynamic system composed of interconnected subsystems (geosphere, hydrosphere, atmosphere, biosphere)
  • These subsystems interact through various cycles and feedback loops to maintain balance and stability
• Scientific methods involve systematic observation, measurement, experimentation, formulation, testing and modification of hypotheses to understand environmental phenomena
• Models and simulations are used to represent and study complex environmental systems and processes (climate models, ecosystem models)
• Sustainability refers to meeting the needs of the present without compromising the ability of future generations to meet their own needs

Environmental Systems & Processes

• Biogeochemical cycles describe the movement and exchange of matter (water, carbon, nitrogen, phosphorus) between the biosphere, geosphere, hydrosphere, and atmosphere
  • Water cycle involves evaporation, transpiration, condensation, precipitation, infiltration, and runoff
  • Carbon cycle includes photosynthesis, respiration, decomposition, and combustion of fossil fuels
• Ecosystems are communities of living organisms interacting with each other and their physical environment
  • Trophic levels (producers, consumers, decomposers) and food webs represent energy flow through ecosystems
• Biodiversity refers to the variety of life at all levels (genetic, species, ecosystem) and is essential for ecosystem functioning and resilience
• Nutrient cycling involves the movement and transformation of essential elements (nitrogen, phosphorus) through ecosystems
• Ecological succession is the gradual process by which ecosystems change and develop over time (primary succession, secondary succession)
• Biomes are large regions characterized by similar climate, vegetation, and wildlife (rainforests, deserts, tundra)
• Interactions between organisms (competition, predation, symbiosis) and their environment (abiotic factors) shape ecosystem dynamics
• Feedback loops can amplify (positive feedback) or dampen (negative feedback) changes in environmental systems

Energy & Matter in the Environment

• Solar radiation is the primary source of energy for Earth's systems, driving weather patterns, ocean currents, and photosynthesis
• Greenhouse gases (carbon dioxide, methane, water vapor) trap heat in the atmosphere, contributing to the greenhouse effect and global warming
  • Anthropogenic emissions from fossil fuel combustion and land use changes have increased greenhouse gas concentrations
• Albedo is the reflectivity of a surface, with lighter surfaces (snow, ice) reflecting more solar radiation and darker surfaces (oceans, forests) absorbing more
• Energy flows through ecosystems from producers to consumers to decomposers, with some energy lost as heat at each trophic level
• Biomass is the total mass of living organisms in an ecosystem and represents stored chemical energy
• Fossil fuels (coal, oil, natural gas) are non-renewable energy sources formed from the remains of ancient organisms
  • Burning fossil fuels releases carbon dioxide and other pollutants into the atmosphere
• Renewable energy sources (solar, wind, hydro, geothermal) are replenished naturally and have lower environmental impacts
• Energy efficiency and conservation reduce energy consumption and environmental impacts associated with energy production and use

Earth's Atmosphere & Climate

• Atmosphere is a layer of gases surrounding Earth, composed primarily of nitrogen (78%) and oxygen (21%)
  • Atmospheric layers include the troposphere, stratosphere, mesosphere, thermosphere, and exosphere
• Weather refers to short-term atmospheric conditions (temperature, humidity, precipitation, wind) in a specific location
• Climate describes long-term average weather patterns and variability over a region
  • Climate zones are determined by factors such as latitude, altitude, ocean currents, and atmospheric circulation patterns
• Atmospheric circulation cells (Hadley, Ferrel, Polar) and global wind patterns (trade winds, westerlies) distribute heat and moisture around the planet
• Jet streams are narrow bands of strong winds in the upper atmosphere that influence weather patterns and air travel
• El Niño and La Niña are periodic fluctuations in ocean temperatures and atmospheric pressure that affect global weather patterns
• Climate change refers to long-term shifts in temperature, precipitation, and other climate variables due to natural and anthropogenic factors
  • Impacts of climate change include rising sea levels, more frequent and intense extreme weather events, and changes in species distributions
• Mitigation strategies aim to reduce greenhouse gas emissions and slow the rate of climate change (renewable energy, carbon pricing, energy efficiency)
• Adaptation strategies help communities and ecosystems cope with the impacts of climate change (flood defenses, drought-resistant crops, ecosystem conservation)

Water Resources & Hydrosphere

• Hydrosphere includes all water on Earth's surface and underground (oceans, lakes, rivers, groundwater, ice caps)
• Oceans cover approximately 71% of Earth's surface and play a crucial role in regulating climate, supporting biodiversity, and providing resources
• Watersheds are areas of land that drain into a common water body (river, lake, ocean)
  • Watershed management involves protecting and restoring water quality and quantity within a drainage basin
• Groundwater is water stored in underground aquifers, replenished by infiltration and depleted by extraction (wells, springs)
  • Aquifers can be confined (bounded by impermeable layers) or unconfined (open to the surface)
• Surface water includes streams, rivers, lakes, and wetlands, which are important for water supply, ecosystem health, and recreation
• Water scarcity occurs when demand for water exceeds available supply, often due to population growth, climate change, and unsustainable water use
• Water pollution can be caused by point sources (factories, sewage treatment plants) or non-point sources (agricultural runoff, urban stormwater)
  • Pollutants include nutrients (nitrogen, phosphorus), chemicals (pesticides, heavy metals), and pathogens (bacteria, viruses)
• Water treatment involves removing contaminants and making water safe for human consumption or ecosystem health
  • Treatment methods include filtration, sedimentation, disinfection (chlorination, UV), and advanced processes (reverse osmosis, activated carbon)

Land & Geological Processes

• Lithosphere is the solid outer layer of Earth, composed of the crust and upper mantle
  • Tectonic plates are large sections of the lithosphere that move and interact at plate boundaries (divergent, convergent, transform)
• Rock cycle describes the formation, alteration, and destruction of rocks through various processes (weathering, erosion, deposition, metamorphism, melting)
  • Igneous rocks form from the cooling and solidification of magma or lava (granite, basalt)
  • Sedimentary rocks form from the deposition and compression of sediments (sandstone, limestone)
  • Metamorphic rocks form from the transformation of existing rocks under heat and pressure (marble, gneiss)
• Soil is a mixture of organic matter, minerals, water, and air that supports plant growth and ecosystem functions
  • Soil formation involves weathering of parent material, addition of organic matter, and development of soil horizons
• Erosion is the removal and transport of rock and soil particles by wind, water, or ice
  • Deposition is the settling of eroded particles in a new location (floodplains, deltas, dunes)
• Geologic hazards include earthquakes, volcanic eruptions, landslides, and sinkholes
  • Hazard mapping and risk assessment help identify vulnerable areas and inform land use planning and emergency response
• Mineral resources are naturally occurring substances that are extracted for economic use (metals, fossil fuels, building materials)
  • Extraction methods include surface mining (open pit, strip mining) and underground mining (shaft, room and pillar)
• Land use planning involves allocating land for various purposes (agriculture, urban development, conservation) based on social, economic, and environmental factors
  • Zoning regulations specify permitted land uses and development standards within different areas of a community

Human Impact & Sustainability

• Population growth and urbanization increase demand for resources (food, water, energy) and generate waste and pollution
  • Carrying capacity is the maximum population size that an environment can sustain indefinitely
• Deforestation is the removal of forests for agriculture, logging, or urban development, leading to habitat loss, soil erosion, and carbon emissions
  • Afforestation and reforestation involve planting trees to restore forest cover and ecosystem services
• Agriculture is the cultivation of crops and raising of livestock for food and other products
  • Sustainable agriculture practices (crop rotation, conservation tillage, integrated pest management) aim to maintain soil health and minimize environmental impacts
• Urbanization is the growth and expansion of cities, which can lead to land use change, habitat fragmentation, and increased resource consumption
  • Sustainable urban design incorporates green spaces, public transit, energy-efficient buildings, and waste reduction strategies
• Pollution is the introduction of harmful substances into the environment (air, water, soil)
  • Types of pollution include air pollution (smog, particulates), water pollution (nutrients, chemicals), and soil pollution (heavy metals, pesticides)
• Waste management involves the collection, treatment, and disposal of solid waste (municipal, industrial, hazardous)
  • Waste reduction strategies include source reduction, recycling, composting, and energy recovery
• Ecological footprint measures the amount of biologically productive land and sea area needed to support a population's resource consumption and waste assimilation
  • Reducing ecological footprint involves adopting sustainable practices (renewable energy, efficient transportation, responsible consumption)
• Environmental policies and regulations aim to protect the environment and promote sustainable development
  • Examples include the Clean Air Act, Clean Water Act, Endangered Species Act, and international agreements (Paris Agreement, Montreal Protocol)

Applications & Case Studies

• Environmental impact assessment (EIA) is a process for evaluating the potential environmental and social impacts of proposed projects or policies
  • EIA steps include screening, scoping, impact analysis, mitigation, and monitoring
• Life cycle assessment (LCA) is a method for assessing the environmental impacts of a product or service throughout its entire life cycle (raw material extraction, manufacturing, use, disposal)
  • LCA can inform product design, material selection, and end-of-life management to minimize environmental impacts
• Ecosystem services are the benefits that humans derive from ecosystems (provisioning, regulating, cultural, supporting)
  • Examples include food production, water purification, carbon sequestration, and recreation
  • Payment for ecosystem services (PES) schemes incentivize land managers to protect and restore ecosystems that provide valuable services
• Renewable energy projects (solar, wind, hydro) can reduce greenhouse gas emissions and dependence on fossil fuels
  • Case studies: Ivanpah Solar Power Facility (California), Gansu Wind Farm (China), Itaipu Dam (Brazil/Paraguay)
• Sustainable urban development projects aim to create livable, resource-efficient cities
  • Case studies: Masdar City (Abu Dhabi), Curitiba (Brazil), Singapore's Green Plan
• Ecological restoration projects seek to restore degraded ecosystems to their natural state
  • Case studies: Everglades restoration (Florida), Loess Plateau restoration (China), Coral reef restoration (Great Barrier Reef)
• Climate change adaptation projects help communities and ecosystems cope with the impacts of climate change
  • Case studies: Netherlands Delta Works (flood protection), Sahel Green Wall (combating desertification), Maldives floating islands (sea level rise adaptation)
• Circular economy initiatives aim to minimize waste and maximize resource efficiency through closed-loop systems
  • Case studies: Industrial symbiosis (Kalundborg, Denmark), Cradle-to-Cradle product design, Repair Cafes (community repair workshops)