Unit 6 - Human Activity and Earth's Atmosphere

Energy

Comes from fossil fuels such as oil, gas, and solar energy.

Combustion

The burning of materials like wood, resulting in the release of heat.

Cellulose

A complex carbohydrate made of glucose molecules linked together.

Biomass

Organic material, including wood, heavily used before the industrial revolution.

Cost-benefit ratio

A measure indicating an investment is worthwhile if the ratio is greater than 1.

Fossil fuels

Natural nonrenewable resources such as coal, petroleum, and natural gas.

Hydraulic fracturing (fracking)

A method for extracting petroleum and natural gas from underground by injecting high-pressure liquids.

Natural gas

A cleaner-burning fossil fuel formed from marine organisms, primarily composed of methane.

Renewable resources

Energy sources that are replenished as quickly as they are used, such as wind, solar, and geothermal.

Efficiency

The ratio of useful energy produced to the energy input in a system, often expressed as a percentage.

Solar energy

Energy from the sun that is converted directly into electricity.

Wind energy

Power generated by wind spinning turbines.

Hydropower

Energy generated by water falling through dams to spin turbines.

Geothermal energy

Energy derived from the heat stored beneath the Earth's surface.

Nuclear power

Energy produced through the splitting of atoms, resulting in large amounts of energy and dangerous waste.

CO₂ and CH₄ Behavior

Carbon dioxide bends and stretches unevenly; methane wobbles and shifts in response to heat.

Safety features in modern cars

Design elements like lighter materials and better construction to improve crash safety and fuel efficiency.

Catalytic converters

Devices that reduce harmful emissions from vehicle exhaust by filtering out pollutants.

Primary energy sources

Energy sources that occur naturally, such as fossil fuels.

Secondary energy sources

Energy forms created from primary sources, such as gasoline derived from crude oil.

coal

• thick layers of dead organic matter —> changed into dense coal by heat and pressure

burned coal

• releases energy, impurities (ex: sulfur, aluminum, mercury, lead)

  • pollute water, air, soil

    • humans rely on healthy functioning ecosystems

subsurface coal mining

• drill holes through earth’s surface, removing coal, transporting it to the surface

  • negatively affects worker health

petroleum - crude oil

• • composed of remains of ancient marine organisms —> buried on ocean floor —> liquid —> carbon

    • trapped under rock formations

      • petroleum is pumped from the ground

  • burned: releases 40-60% more energy/gram than coal

  • refined to make gasoline

    • special blends of gasoline (hydrocarbons) + tax = reduced emissions

    • transported by pipelines, trains, trucks

risk of transport

• risks: explosion/spills —> affects properties of buildings