# Assessment Instructions: ASTR 120 Problem Set 04

## Inputs to Inspect

- Student submission for Problem Set 04.
- Student problem set: `materials/ASTR120/problem-sets/problem-set-04.html`.
- Instructor solution key: `materials/ASTR120/problem-sets/problem-set-04-solutions.html`.
- Course syllabus and grading policy: `materials/ASTR120/syllabus.html`.
- Lecture artifacts for Lectures 07-08.

## Grading Standard

Assess surface chronology, density calculations, Mars evidence ranking, units, assumptions, and interpretive restraint. Full credit requires separating water evidence from life claims.

## Problem-Level Criteria

- Problem 1: crater density, ratio, relative sequence, and lunar sample calibration.
- Problem 2: Moon and Mercury densities with correct unit conversion and cautious core inference.
- Problem 3: ranking, past/present classification, ambiguity, and water-versus-life distinction.
- Problem 4: area conversion, porosity, mass calculation, preservation fraction, and delta interpretation.

## Feedback Requirements

Classify issues as arithmetic, unit conversion, conceptual chronology, evidence interpretation, or communication. Give revision guidance targeted to the first incorrect step.

## Integrity and Evidence Checks

Flag unsupported mission claims, copied ranking text, outside data without citation, and calculations that cannot be reproduced from submitted work.

## Resubmission Pathway

Students may revise with a change note explaining corrected calculations or interpretations. Preserve high standards for evidence and units.