AP Environmental Science Math

Important Math to study for APES exam

Doubling Time

Doubling Time (years) = 70 ÷ Growth Rate (%)

Growth Rate (%)

Growth Rate (%) = (CBR − CDR) ÷ 10

Population Change

Population Change = (Births + Immigration) − (Deaths + Emigration)

Crude Birth Rate (CBR)

CBR = (Births ÷ Total Population) × 1000

Crude Death Rate (CDR)

CDR = (Deaths ÷ Total Population) × 1000

Percent Change

% Change = [(New − Old) ÷ Old] × 100

Energy Efficiency

Efficiency (%) = (Useful Output ÷ Total Input) × 100

Rule of 70

Doubling Time = 70 ÷ Annual Growth Rate (%)

Trophic Level Energy Transfer

Available Energy = Previous Level × 0.10

GPP and NPP

NPP = GPP − Respiration

kWh to Joules Conversion

1 kWh = 3.6 × 10⁶ Joules

Birth Rate (%)

Birth Rate (%) = (Number of Births ÷ Population) × 100

Death Rate (%)

Death Rate (%) = (Number of Deaths ÷ Population) × 100