The Suitcase Test
📖 The Suitcase Test
Density is all about how much matter (mass) is squeezed into a given space (volume). But why do different materials have different densities? There are two factors at the particle level:
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🧠 Memory Aid
The equation triangle for density:
Write m at the top of a triangle, ρ (rho) bottom-left, V bottom-right. Cover the quantity you want:
- Cover ρ: density = m ÷ V
- Cover m: mass = ρ × V
- Cover V: volume = m ÷ ρ
Remember the symbol: ρ is the Greek letter "rho" — think "rho = ρack it in" (how tightly packed the material is).
Float or sink rule: "If density is greater than water (1000 kg/m³), it will sink. If less, it will float." — The word LESS has 4 letters, and so does FLOAT. More has 4 letters too, but think: MORE density = MORE sinking.
Now try it yourself
Quiz · Question 1 of 13
What is the correct equation for density?
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This topic in real past papers
Every real exam question we've found on density, with a full worked answer.