This topic summary covers Topic Summary: Density within Density for GCSE Physics. Revise Density in Particle Model for GCSE Physics with 13 exam-style questions and 30 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 13 of 13 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 13 of 13
Practice
13 questions
Recall
30 flashcards
Topic Summary: Density
Key Terms
- Density (ρ): mass per unit volume
- Displacement: volume of fluid pushed aside by an object
- Upthrust: upward force on a submerged object
- Regular solid: shape with calculable volume (cube, cylinder)
- Irregular solid: shape needing displacement method
Key Facts
- Density is a property of the material, not the object size
- Water density = 1000 kg/m³ = 1 g/cm³ (benchmark)
- Objects float if density < fluid density
- Objects sink if density > fluid density
- Gases are ~1000× less dense than solids/liquids
Key Equations
- ρ = m / V (density = mass ÷ volume)
- Units: kg/m³ or g/cm³
- Conversion: 1 g/cm³ = 1000 kg/m³
- Displacement volume: V = V₂ − V₁
- Higher: P = ρgh (fluid pressure)
Exam Tips
- Always show units in density calculations
- For displacement: volume = final − initial reading
- Air bubbles on object = source of error in practical
- Cutting a material in half does NOT change its density