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A1.1.6—Physical properties of water for aquatic animals

Compared with air, water is denser, more viscous, more thermally conductive and more temperature-stable, shaping aquatic organisms’ support, movement and insulation.

Syllabus
First assessment 2025
Objective
A1.1.6
Level
HL

Exam analysis

Chance of appearing3%of analysed past papers
Latest appearanceNovember 2025
Most common paper—
Typical marks1–2

Common command terms

  • Identify
  • Describe
  • Distinguish

Scoring notes

Common mistake
Confusing thermal conductivity with specific heat capacity.

Recent exam appearances

November 2025Paper1A HL · TZ11[ 1 ]A1.1.6—Physical properties of water for aquatic animals
May 2025Paper2 HL · TZ22(b)[ 2 ]A1.1.6—Physical properties of water for aquatic animals
May 2025Paper2 HL · TZ22(a)[ 2 ]A1.1.6—Physical properties of water for aquatic animals
May 2025Paper1A HL · TZ21[ 1 ]A1.1.6—Physical properties of water for aquatic animals
Practice this objective

Coverage 2025–2025 · Updated 14 Jul 2026

Concept essentials

  • Water is denser and more buoyant than air.
  • Higher viscosity increases resistance to movement.
  • Higher thermal conductivity increases heat loss from animals.
  • High specific heat capacity stabilises aquatic temperatures.
  • Aquatic adaptations match distinct physical challenges.
ConceptIB Biology HL