Earth Science Regents Reference Table & Formulas
The official Earth Science Reference Tables (ESRT), plus key Earth Science formulas, concepts, and vocabulary to know for the exam.
The official Earth Science Reference Tables (ESRT)
Provided with every Earth Science Regents booklet. Current edition: 2011 edition (current).
What's inside the Earth Science Reference Tables (ESRT):
- Generalized Geologic Time Scale and Rock Cycle in Earth's Crust
- Mineral identification key and Scheme for Igneous Rock Identification
- Generalized Landscape Regions of NYS map
- Tectonic Plates, Earthquake P/S Wave, and Volcano maps
- Climate, weather, and water-cycle charts
- Planetary motion and solar-system data
- Equations, eccentricity, gradient, rate of change, density
Earth Science is THE most reference-table-driven Regents. Many questions are direct table reads. Spend the first 10 minutes of every study session just navigating the ESRT.
Key Earth Science formulas
| Name | Formula | What it's for |
|---|---|---|
| Density | $D=\dfrac{m}{V}$ | Mass per unit volume. Independent of sample size, so it identifies a material. (On the ESRT.) |
| Eccentricity of an orbit | $e=\dfrac{\text{distance between foci}}{\text{length of major axis}}$ | How out-of-round an ellipse is: 0 is a perfect circle, closer to 1 is more stretched. (On the ESRT.) |
| Gradient | $\text{gradient}=\dfrac{\text{change in field value}}{\text{distance}}$ | How fast a field (elevation, temperature, pressure) changes over distance. Steep contours mean a high gradient. (On the ESRT.) |
| Rate of change | $\text{rate}=\dfrac{\text{change in value}}{\text{time}}$ | How fast any measured quantity changes over time. (On the ESRT.) |
| Percent deviation (error) | $\%\text{ deviation}=\dfrac{|\text{measured}-\text{accepted}|}{\text{accepted}}\times100$ | How far a measurement is from the accepted value. (On the ESRT.) |
Key concepts
- Plate boundaries — Divergent (plates separate, new crust at mid-ocean ridges), convergent (collide, subduction and mountains), and transform (slide past, earthquakes).
- The rock cycle — Igneous (cooled magma), sedimentary (compacted sediment), and metamorphic (heat and pressure) rocks continuously transform into one another.
- Radioactive dating — Each radioactive isotope decays over a fixed half-life. Comparing remaining isotope to decay product gives an absolute age. Carbon-14 for once-living material; uranium for old rock.
- Relative dating — Law of superposition: lower layers are older. Cross-cutting features and index fossils order events without exact ages.
- Earth's motions & seasons — Rotation (24 h) causes day and night; revolution plus the 23.5 degree tilt causes the seasons by changing the angle of insolation, not distance to the Sun.
- Reading a topographic map — Contour lines join points of equal elevation. Close lines mean steep ground; contours point upstream (V's) when crossing a river.
Must-know vocabulary
- Isoline — A line connecting points of equal value (contour = elevation, isotherm = temperature, isobar = pressure).
- Epicenter — The point on Earth's surface directly above where an earthquake originates; located using P- and S-wave arrival times.
- Index fossil — A fossil from an organism that was widespread but existed only briefly, so it pins down the age of a rock layer.
- Insolation — Incoming solar radiation. Greatest when the Sun is high and rays strike at a steep angle.
- Porosity vs permeability — Porosity is how much empty space a material has; permeability is how easily water flows through it.
Frequently asked questions
Do you get a reference table on the Earth Science Regents?
Yes. The official Earth Science Reference Tables (ESRT) is provided with every Earth Science Regents booklet, so practice with it open.
What formulas do you need for the Earth Science Regents?
The most-used Earth Science formulas are on this page with what each one is for. There are 5 key formulas to know.