APES Math Formulas Flashcards
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| 13832283146 | population density | Population ____________________ area | 0 | |
| 13832287261 | Birth/death rate | # of births or deaths per year -------------------------------- Total population | 1 | |
| 13832296657 | Crude birth/death rate | multiply the rate by 1,000 example: 23,452 births ----------------- = 0.025 = 2.5% birth rate 942,721 people 25 = crude birth rate | 2 | |
| 13832329669 | r (growth rate) - from crude figures | crude births - crude deaths -------------------------------- = r 10 (we divide by 10 because we multiplied by 1000 to get the crude rate - this makes it the same as multiplying by 100 which give us the percent) | 3 | |
| 13832356718 | r (growth rate) - from actual population numbers | births - deaths ---------------- = r (or multiply by 100 to express as r%) total pop. | 4 | |
| 13832377559 | r (growth rate) - from crude figures including I and E | (CBR + I) - (CDR + E) ----------------------- = r (or multiply by 100 for r%) 10 | 5 | |
| 13832398271 | r (growth rate) - from actual population numbers including I and E | (Births + Immigration) - (Deaths + Emigration) ------------------------------------------------- = r total pop. *(multiple r by 100 for r%) | 6 | |
| 13832406061 | Doubling time (rule of 70) | 70 0.7 ------------------- OR --------------- r (in percent form) r (in decimal form) | 7 | |
| 13832449068 | Percent change | new - old ----------- x 100% old *remember NOO | 8 | |
| 13832457732 | Net Primary Productivity | NPP = Gross Primary Productivity - Respiration OR NPP = GPP - R *Remember, if you get stuck in a NET you would say GRR | 9 | |
| 13832487985 | Trophic levels | 90% of energy/biomass is lost as you move up a trophic level OR 10% of energy is passed onto the next trophic level | 10 | |
| 13832503501 | Density | mass ------ volume | 11 | |
| 13832518113 | pH scale | 1 # decrease on scale = 10x H+ (acidity) Example: A solution with pH of 2 has 1000 times more H+ ions than a solution with a pH of 5. This is because 5-2 = 3. So three tens multiplied = 10 x 10 x 10 = 1000 | 12 | |
| 13832528908 | half-life | length of time required for half of the radioactive atoms in a sample to decay |  | 13 |
| 13832537720 | Watts | Joules ------- second | 14 | |
| 13832817343 | kWh (kilowatt hour) | Usually, we combine kW and h to get kWh. Your electricity bill is in kWh. Example: A TV uses 200 watts and runs for 6 hours. This is 1200Wh OR 1.2kWh. | 15 |