All Categories

Environmental Science

Sustainability, energy, ecology, and earth-science formulae.

Carbon Footprint

Basic
CO2=E×fCO_2 = E \times f

Emissions from energy use and an emission factor.

View details

Wind Turbine Power

Advanced
P=12ρAv3CpP = \frac{1}{2}\rho A v^3 C_p

Power extracted from wind by a turbine.

View details

Betz Limit

Advanced
Cp,max=0.593C_{p,max} = 0.593

Maximum fraction of wind energy a turbine can capture.

View details

Solar Panel Output

Intermediate
P=A×r×H×PRP = A \times r \times H \times PR

Energy output of a photovoltaic array.

View details

Radioactive Decay

Intermediate
N=N0(12)t/t1/2N = N_0\left(\frac{1}{2}\right)^{t/t_{1/2}}

Amount remaining after a number of half-lives.

View details

pH

Intermediate
pH=log10[H+]pH = -\log_{10}[H^+]

Acidity from hydrogen ion concentration.

View details

Energy Consumption

Basic
E=P×tE = P \times t

Electrical energy used over time.

View details

Exponential Population Growth

Intermediate
N=N0ertN = N_0 e^{rt}

Growth of a population at a constant rate.

View details

Logistic Growth

Advanced
dNdt=rN(1NK)\frac{dN}{dt} = rN\left(1 - \frac{N}{K}\right)

Population growth that slows as it nears carrying capacity.

View details

Water Use Intensity

Basic
WUI=VwaterOutputWUI = \frac{V_{water}}{Output}

Water consumed per unit of product or service.

View details

Albedo

Intermediate
α=reflectedincident\alpha = \frac{\text{reflected}}{\text{incident}}

Fraction of solar radiation reflected by a surface.

View details

Energy Payback Ratio

Intermediate
EPR=EgeneratedEinvestedEPR = \frac{E_{generated}}{E_{invested}}

Energy produced over a lifetime divided by energy to build it.

View details

Sound Level

Intermediate
L=10log10II0L = 10\log_{10}\frac{I}{I_0}

Sound intensity level in decibels.

View details

Richter Magnitude Energy

Advanced
log10E=4.8+1.5M\log_{10}E = 4.8 + 1.5M

Approximate energy released by an earthquake.

View details

Dilution Equation

Basic
C1V1=C2V2C_1 V_1 = C_2 V_2

Relates concentration and volume before and after dilution.

View details