Construct, use and evaluate models, distinguish a fact, hypothesis, theory and law, and explain how scientific knowledge is built from evidence and changes over time (Virginia 2018 Earth Science SOL ES.1).

What this topic is asking

Virginia Earth Science SOL standard ES.1 includes the nature of science: what counts as a hypothesis, a theory or a law; how scientists use models; and how knowledge is built from evidence and changes as new evidence appears. EOC items test this directly ("which is a theory?") and indirectly, by asking you to judge a model's usefulness or to tell an observation from an inference. Earth science relies on models constantly, from the rock cycle to the layered Earth to Moon-phase diagrams, so understanding what a model is matters across the course.

Hypothesis, theory and law

The most tested misconception is that a theory is "just a guess" or that a theory becomes a law once proven. In science, theory is one of the strongest terms there is: plate tectonics and the Big Bang are theories because they explain enormous bodies of evidence. Laws and theories are different kinds of statement (description versus explanation), not different ranks on a ladder.

Models and their limitations

Earth science is full of models because so much of it is too large (the planet), too slow (mountain building), too far (stars) or too deep (the core) to observe directly. The skill the EOC rewards is judging what a model shows well and what it leaves out.

How scientific knowledge is built and why it changes

Scientific knowledge rests on empirical evidence: data from observation and experiment, gathered with controls and repeated trials. New claims are checked by peer review (other scientists scrutinize the work) and must be reproducible. Because science follows the evidence, an accepted idea can be revised or replaced when better evidence appears, which is a strength, not a weakness. Plate tectonics, for example, replaced earlier views once seafloor-spreading evidence accumulated. This is why "science can never change" is wrong: durable conclusions are held with confidence, but the door to revision stays open.

Observation versus inference

Science, technology and ethics

Advances in technology drive science forward: better telescopes, seismographs, satellites and GPS reveal data earlier scientists could not collect. Earth science also raises ethical and societal questions, for example how to use mineral and energy resources responsibly, how to balance development against environmental impact, and how to communicate hazard risk honestly. Recognizing that scientific information informs public decisions is part of the nature-of-science strand.

Try this

Q1. Explain the difference between a scientific law and a scientific theory. [2]

• Cue. A law describes what happens (a consistent pattern or relationship); a theory explains why a broad range of observations occur, backed by much evidence.

Q2. Give one strength and one limitation of using a stream table to model a real river. [2]

• Cue. Strength: it shows erosion, transport and deposition you can watch. Limitation: it is far smaller and faster, and cannot reproduce the full scale, sediment or time of a real river.