← Earth and Environmental Science syllabus

VirginiaEarth and Environmental Science

Reporting Category: Earth's History and Surface Processes

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do fossils form, and how do they help correlate rocks and divide geologic time?

Explain how fossils form and how index fossils correlate rock layers, and describe the divisions and major events of the geologic time scale, including in Virginia (Virginia 2018 Earth Science SOL ES.9).
A SOL-level answer on fossils and geologic time for the Virginia Earth Science EOC: how fossils form, what makes a good index fossil, using fossils to correlate distant rock layers and infer ancient environments, the eon-era-period divisions, major events like mass extinctions, and Virginia's fossil record, with worked exam questions.
13 min answer →

How does radioactive decay let geologists put an actual number of years on a rock?

Explain radioactive decay and half-life, and calculate the age of a sample or the fraction of parent remaining using the number of half-lives that have passed (Virginia 2018 Earth Science SOL ES.9).
A SOL-level answer on absolute dating for the Virginia Earth Science EOC: what radioactive decay and half-life mean, the parent-to-daughter ratio, how to count half-lives to find an age or the fraction remaining, why carbon-14 dates young organic material and uranium dates ancient rock, and how Earth's age (about 4.6 billion years) is known, with worked calculations.
13 min answer →

How do you read elevation, slope and stream direction from a topographic map's contour lines?

Read a topographic map: interpret contour lines and the contour interval, find elevation and relief, judge slope steepness from contour spacing, and use the rule of Vs to find stream direction (Virginia 2018 Earth Science SOL ES.1 and ES.6).
A SOL-level answer on topographic maps for the Virginia Earth Science EOC: what contour lines and the contour interval mean, how to find elevation and total relief, how contour spacing shows slope steepness, how the rule of Vs gives stream direction, and how to calculate gradient, with worked exam questions.
13 min answer →

How do geologists put rock layers in order and read the history recorded in a cross section?

Apply the principles of relative dating (superposition, original horizontality, cross-cutting relationships, inclusions and unconformities) to sequence events in a geologic cross section (Virginia 2018 Earth Science SOL ES.9).
A SOL-level answer on relative dating for the Virginia Earth Science EOC: the law of superposition, original horizontality, cross-cutting relationships, inclusions and unconformities, the difference between relative and absolute age, and how to sequence the events in a geologic cross section, with worked exam questions.
13 min answer →

What is soil made of, how do its horizons form, and why does soil matter as a resource?

Describe the components of soil and the soil horizons, explain the factors that control soil formation, and evaluate soil as a resource that can be conserved or lost to erosion (Virginia 2018 Earth Science SOL ES.6 surface processes).
A SOL-level answer on soil for the Virginia Earth Science EOC: the components of soil (weathered rock, humus, water, air), the O, A, B and C horizons, the factors that control soil formation (climate, parent material, time, organisms, slope), residual versus transported soil, and why soil conservation matters, with worked exam questions.
12 min answer →

How do weathering, erosion and deposition break down, move and lay down Earth's materials?

Distinguish mechanical and chemical weathering, identify the agents of erosion and deposition, and explain how particle size, sorting and water velocity control where sediment is deposited (Virginia 2018 Earth Science SOL ES.6 surface processes).
A SOL-level answer on surface processes for the Virginia Earth Science EOC: mechanical versus chemical weathering and what speeds each, the agents of erosion (water, wind, ice, gravity), how water velocity controls the size of sediment carried and deposited, sediment sorting and rounding, and landforms like deltas and moraines, with worked exam questions.
13 min answer →