DENSITY AND PRESSURE
3 marks · NormalExplain, using the idea of density and correct units, why a steel block sinks but a wooden block of the same size floats when placed in water.
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Steel sinks because its density (in kg/m³) is greater than that of water, while wood floats because its density is less than water.
Also accept: Steel sinks as its density is greater than water; wood floats as its density is less.
Common mistakes: Just saying wood is lighter or steel is heavier without density reference.
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Marking points
B1 · 1 mark · Explains floating/sinking as a result of comparing densities
B2 · 1 mark · Refers correctly to the unit kg/m³ for density
B3 · 1 mark · States that steel has a higher density than water; wood lower
Worked solution
A steel block sinks because its density (measured in kg/m³) is greater than the density of water. A wooden block floats because its density is less than that of water.