PHY 105 at Southern New Hampshire University is a three-credit survey of the major themes in geology. The catalog lists plate tectonics, the rock cycle, surface processes and the concept of geologic time.
Although it carries a PHY code, the course is earth science. The key challenge is thinking in very long time scales and connecting small observations, such as a rock layer or a mountain range, to large processes.
Course at a Glance
| Item | Details |
|---|---|
| University | Southern New Hampshire University |
| Course code | PHY 105 |
| Credits | 3 |
| Subject | Geology (earth science) |
| Prerequisites | None listed in the SNHU catalog |
| Typical work | Quizzes, short written responses, data or map exercises (check your course for the exact list) |
What PHY 105 Covers
| Theme (from the catalog) | Core ideas |
|---|---|
| Plate tectonics | Moving lithospheric plates; divergent, convergent and transform boundaries; earthquakes, volcanoes and mountain building |
| The rock cycle | Igneous, sedimentary and metamorphic rocks and the processes that convert one to another |
| Surface processes | Weathering, erosion, deposition and the landforms they create |
| Geologic time | Relative and absolute dating, and the scale of earth history |
Key Concepts with Worked Examples
Plate Motion as a Rate Problem
Many questions turn motion into a distance over time. Convert units carefully.
Invented illustration: If two plates separate at 2 cm per year, then over 100 million years the separation is 2 cm x 100,000,000 = 200,000,000 cm, which is 2,000 km. Small yearly motion adds up to ocean-basin scale.
Reading Time from Rock Layers
Relative dating uses principles such as superposition (older layers lie beneath younger ones unless disturbed) and cross-cutting relationships (a feature that cuts through a layer is younger than that layer). Absolute dating uses radioactive decay: after one half-life, half of the parent isotope remains; after two, one quarter.
The Rock Cycle Is a Set of Pathways
Rocks do not follow a single loop. Sedimentary rock can be melted to form igneous rock, or metamorphosed under heat and pressure, depending on conditions. Draw arrows and label the process on each.
Typical Assignments and How to Approach Them
| Assignment type | What it tests | How to approach it |
|---|---|---|
| Quizzes | Vocabulary and processes | Make flashcards pairing each term with a process and an example |
| Short written responses | Explaining a process in sequence | Give the cause, the steps and the result in order |
| Data or map exercises | Interpreting evidence | State what the data show before explaining why |
| Applied reports | Linking concepts to a place or event | Choose a specific location and tie two concepts to it |
Where Students Get Stuck
- Time scales. Practice converting between years, thousands and millions of years without losing zeros.
- Boundary types. Learn what happens at each plate boundary and an example of each.
- Weathering versus erosion. Weathering breaks rock down in place; erosion moves it.
- Rock classification. Link texture and formation to rock type, not just names.
Study Tips for PHY 105
- Draw one annotated diagram per theme and redraw it from memory.
- Pair each process with a real example place, such as a named boundary or landform.
- Build a timeline of earth history with the main divisions in order.
- Use the same terms as your course materials in written answers.
Worked Example: Reading a Cross-Section
Questions often show a diagram of layers and ask for the order of events. Work from the bottom upwards, then look for features that cut across.
Invented illustration: A diagram shows three horizontal sedimentary layers (A at the bottom, B in the middle, C at the top) and a vertical igneous dike cutting through A and B but not C. By superposition, A is oldest, then B, then C. The dike cuts A and B, so it is younger than both. It does not cut C, so C was deposited after the dike formed (or the dike never reached C). The sequence is A, B, dike, C.
Vocabulary to Master
| Term | Plain-language meaning |
|---|---|
| Lithosphere | The rigid outer layer of Earth, broken into plates |
| Subduction | One plate sinking beneath another at a convergent boundary |
| Weathering | Breakdown of rock at or near the surface |
| Erosion | Removal and transport of weathered material |
| Half-life | Time for half of a radioactive isotope to decay |
Writing Short Geology Answers
Questions ask you to explain a process, not recite a list. A reliable pattern for a four to six sentence answer is below.
- Name the process and where it occurs.
- Say what drives it, such as heat from the mantle or gravity on a slope.
- Describe the steps in order.
- State the result, such as a landform or rock type.
- Give one example location or feature.
Illustration (short answer on subduction): Subduction happens at convergent boundaries where a denser oceanic plate meets another plate. The cooler, denser plate sinks into the mantle. As it descends it releases water that lowers the melting point of the overlying mantle, producing magma that feeds volcanoes. The result is a volcanic arc and a deep trench, as seen around parts of the Pacific.
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Frequently Asked Questions
The catalog lists plate tectonics, the rock cycle, surface processes and the concept of geologic time.
It has a PHY code, but its content is geology.
None are listed in the SNHU catalog.
Make a table of boundary type, plate motion, typical features and an example location.
It uses simple calculations, such as rates and half-lives, but mostly asks you to explain processes.
Yes. Send the draft and instructions for feedback on accuracy, structure and clarity.