task_physics__buoyancy_density__object_density_value

Summary

• Domain: physics
• Scene id: buoyancy_density
• Implementation scene: buoyancy_density
• Implementation source: src/trace_tasks/tasks/physics/buoyancy_density/object_density_value.py

Task Contract

Computes the density of a floating object from the visible submerged fraction and the shown liquid density.

Program Contract

Program: number(liquid_density * submerged_fraction(floating_object, waterline, equal_part_marker)); scene=buoyancy_density; scope=object_density_value

Candidate set: the visible floating object, liquid region, level markers, and density labels inside the object_density_value objective scope. Operands: floating_object (semantic_role, allowed visible_divided_floating_body, source program_schema_concrete); waterline (semantic_role, allowed visible_liquid_surface_crossing_object, source program_schema_concrete); equal_part_marker (semantic_role, allowed visible_equal_division_marker, source program_schema_concrete); liquid_density (query_operand, allowed visible_density_label_g_cm3, source program_schema_concrete). Operation: evaluate number over the candidate set using the visible quantities, relations, branch semantics, and formulas encoded in the program expression; generation enforces a unique final answer. Output binding: answer uses the number schema; Answer precision: one_decimal Annotation witnesses: bbox witnesses from the finalized render. Annotation marks one bounding box around the floating object. The waterline, density label, and fraction marker remain visible context in the image and trace metadata, but they are not public annotation witnesses. Query ids: single.

Reasoning Operations

Families: formula_evaluation

Query Branches

Query id	Program schema
single	liquid_density * submerged_fraction(floating_object, waterline, equal_part_marker); scene=buoyancy_density; scope=object_density_value

Program Metadata

• Program signatures: physics.buoyancy_density.object_density
• Base program contract: liquid_density * submerged_fraction(floating_object, waterline, equal_part_marker); scene=buoyancy_density; scope=object_density_value
• Parameter axes: scene_variant, object_shape (block, rounded_block), submerged_fraction, liquid_density, target_answer
• Arguments:
• floating_object: semantic_role; allowed visible_divided_floating_body; source program_schema_concrete
• waterline: semantic_role; allowed visible_liquid_surface_crossing_object; source program_schema_concrete
• equal_part_marker: semantic_role; allowed visible_equal_division_marker; source program_schema_concrete
• liquid_density: query_operand; allowed visible_density_label_g_cm3; source program_schema_concrete
• Argument metadata status: curated
• Supported query ids: single

Answer Contract

• Answer schema: number
• Answer precision: one_decimal
• Generator answer_gt.type: number
• The answer value is the object density in g/cm^3 rounded to one decimal place.

Annotation Contract

• Annotation schema: bbox
• Generator annotation_gt.type: bbox
• Annotation marks one bounding box around the floating object.
• The waterline, density label, and fraction marker remain visible context in the image and trace metadata, but they are not public annotation witnesses.
• Annotation and answer must be projected from the same generated execution trace, not inferred from pixels or prompt text.

Prompt And Trace Requirements

• Prompt text must come from the physics prompt bundles, with scene and task/query layers selected deterministically and recorded in metadata.
• Render randomness, sampled fonts/styles, scene variant, object shape, submerged fraction, liquid density, target answer, and verifier payloads must be explicit in the instance trace.
• Diagrams must keep the liquid surface, floating object divisions, fraction marker, and liquid-density label readable.
• Object color, liquid color, object shape, and scene variant are non-semantic visual variation axes and must not be tied to the answer.