One of the most common APES exam questions students have is:
“Does the AP Environmental Science exam give you a formula sheet?”
The short answer: No — you need to memorize most of the formulas.
Unlike AP Physics or AP Chemistry, APES doesn’t hand you equations during the exam. This makes it crucial to know them cold before test day.
📋 The Essential APES Formulas You Must Memorize
1. Population Growth
- Formula: Growth Rate (%)=Births−DeathsTotal Population×100\text{Growth Rate (\%)} = \frac{\text{Births} - \text{Deaths}}{\text{Total Population}} \times 100
- Tip: For doubling time, use the Rule of 70: Doubling Time (years)=70Growth Rate (%)\text{Doubling Time (years)} = \frac{70}{\text{Growth Rate (\%)}}
2. Net Primary Productivity (NPP)
- Formula: NPP=GPP−Respiration\text{NPP} = \text{GPP} - \text{Respiration}
- Where:
- GPP = Gross Primary Productivity
- Measured in energy per area per time (e.g., kcal/m²/year)
3. Energy Efficiency
- Formula: Efficiency (%)=Energy OutputEnergy Input×100\text{Efficiency (\%)} = \frac{\text{Energy Output}}{\text{Energy Input}} \times 100
- Example: Comparing the efficiency of coal vs. solar panels.
4. pH Calculations
- Formula: pH=−log[H+]\text{pH} = -\log[\text{H}^+]
- APES Context: Used in acid rain, ocean acidification, and water chemistry.
5. Water Flow
- Formula: Q=V×AQ = V \times A
- Where:
- Q = Flow rate
- V = Velocity of water
- A = Cross-sectional area of stream/river
6. Half-Life
- Formula: Nt=N0×(12)t/TN_t = N_0 \times \left(\frac{1}{2}\right)^{t/T}
- Where:
- NtN_t = Remaining amount
- N0N_0 = Initial amount
- tt = Time elapsed
- TT = Half-life
7. Energy Unit Conversions
- 1 kWh = 1,000 watts × 3,600 seconds = 3.6 × 10⁶ joules
- 1 MW = 1,000 kW
📌 How Formulas Are Tested on the APES Exam
- Multiple Choice: Quick calculations like energy efficiency or growth rate.
- FRQs: Often require multi-step calculations followed by an explanation of the environmental significance.
- Data Analysis: Using formulas to interpret lab results or real-world scenarios.
💡 Memorization Tips
- Make flashcards with the formula on one side and an example problem on the other.
- Use real environmental scenarios instead of random numbers.
- Practice under timed conditions to build speed.
Final Word from RevisionDojo:
The APES exam expects you to know your formulas without hints. Master these equations, practice them daily, and you’ll avoid losing easy calculation points.
