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Environmental: explore STEM content (page 13 of 27) · openstem
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Search the community's STEM library — free to study, yours to make your own.
Environmental
Geology, climate and the environment on openstem — flashcards, notes, quizzes, plots and sketches shared by the community. Study free, or clone anything into your library.
Why is sound intensity measured on a logarithmic decibel scale rather than a linear one?1 / 8
Human hearing spans an enormous intensity range — roughly 12 orders of magnitude from the threshold of hearing to the threshold of pain — and perceived loudness itself scales roughly logarithmically with physical intensity. A logarithmic decibel scale (referenced to I0, the threshold of hearing) compresses that huge range into a manageable 0-140 dB scale that also better matches subjective loudness perception.
The Closure Problem Reynolds-averaging the governing fluid equations to separate mean flow from turbulent fluctuations introduces new unknown turbulent flux terms (Reynolds stresses, e.g. u'w') that have no equation of their own within the
Environmental
Environmental · L5 · Boundary Layer Turbulence and Monin-Obukhov Similarity Theory
Predicting Impact Before It Happens An environmental impact assessment (EIA) is the formal regulatory process most jurisdictions require before approving major projects — mines, dams, highways, power plants — so that likely environmental co
The net difference between how much ice/snow a glacier gains (accumulation) and loses (ablation) over a year, usually expressed in metres of water equivalent. A positive balance means the glacier is growing; a negative balance means it's shrinking.
Environmental
Environmental · L3 · Glacial Mass Balance & Sea-Level Contribution
Solar: Turning Light Directly Into Current A solar photovoltaic (PV) cell is a thin slice of silicon treated so that one layer has a surplus of electrons and the other has a deficit. When a photon of sunlight strikes the silicon with enough
Environmental
Environmental · L2 · How Renewable Energy Systems Work
A Fast-Growing Waste Stream E-waste — discarded phones, computers, TVs, and appliances — is one of the fastest-growing waste categories in the world, driven by falling electronics prices, rapidly changing technology, and devices often desig
A Definition That Still Anchors the Field The 1987 UN report Our Common Future, chaired by Gro Harlem Brundtland, gave sustainable development its most widely used definition: development that meets the needs of the present without compromi
Environmental
Environmental · L3 · Sustainable Development & the Triple Bottom Line
ATo make harvesting more convenient for machineryBTo restore depleted soil nutrients and break pest and disease cyclesCTo grow the same crop faster each yearDTo eliminate the need for any water at all
Why can't most organisms use atmospheric N₂ directly?
AN₂ is toxic to most organismsBN₂'s triple bond is too strong for most organisms to breakCThere isn't enough N₂ in the atmosphereDN₂ only exists in soil, not air
AThe upper boundary of the zone where the ground is fully saturated with waterBA man-made structure that holds groundwaterCThe deepest point any aquifer reachesDA synonym for a river or lake
Layers of the Ocean The ocean is not the same all the way down. As you go deeper, sunlight fades, temperature drops, and pressure builds — so scientists divide the ocean into layers, called zones, based on how much light reaches them. Going