S2 Science: Density And Floating (Paper 4 (error Clinic))

S2 Science: Density and Floating (Paper 4 (error clinic))

2026-11-14

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Tutor Prep Guide · Probability scale, favourable over total outcomes, comparing and expected counts

S2 Science: Density and Floating (Paper 4 (error clinic))

This paper targets the usual errors: the three directions of the density formula, displacement, floating by comparison and the unchanged density.

Direct answers　In error clinic work, note the original mistake, then state the right thing to compare against. Floating is a comparison, not a weight; cutting is a ratio, not a change.

01　Paper details (check answers afterwards)

Item	Detail
Questions	10
Suggested time	20
Difficulty mix	Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1
Chapter	Chapter: S2 Science: Density and Floating
Level	S2

02　Questions (10 items)

FoundationWhat is the definition of density?
FoundationAn object of mass 200 g has a volume of 40 cm³. Find its density.
FoundationA substance of density 1.5 g/cm³ has a mass of 90 g. Find its volume.
IntermediateA stone raises a cylinder reading from 60 mL to 80 mL. What is its volume?
IntermediateA block of density 0.7 g/cm³ is placed in water. Does it float or sink?
IntermediateAn object of density 1.05 g/cm³ is placed in water. Does it float or sink?
ChallengeAn object of mass 60 g has a volume of 30 cm³. Find its density.
ChallengeHalf of an object of density 3 g/cm³ is cut away. What is the density of the remainder?
ChallengeA 500 g block floats on water. How many cm³ of water does it displace?
Error redoA student thinks any low density object floats. What is wrong?

03　Answers and one-line notes

#	Answer	One-line note
1	The mass in unit volume	Density tells how much mass sits in a unit of volume, and a bigger number means packed tighter.
2	5 g/cm³	200 divided by 40 is 5, denser than water, so it would sink.
3	60 cm³	90 divided by 1.5 gives 60 cm³.
4	20 cm³	80 minus 60 is 20 mL, which is 20 cm³.
5	It floats	0.7 is less than 1.0, so it floats with part of it above the surface.
6	It sinks, even a slight excess is enough	Anything denser than the liquid sinks, and a margin of 0.05 is enough.
7	2 g/cm³	60 divided by 30 is 2 g/cm³.
8	Still 3 g/cm³	Both mass and volume halve, so density is unchanged, which is a common trap.
9	500 cm³	A floating body displaces its own weight, and 500 g of water is 500 cm³.
10	It depends on the liquid, since a 0.9 object sinks in oil of 0.8	Floating depends on the object against the liquid in use, not against water alone.

04　What to do after marking

After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
Repeat the same item two days later; move to the next paper only when both attempts are correct.
Parents only need the answer and note columns; there is no need to explain every item.

There is one density formula: density equals mass divided by volume; to judge floating, compare the object density with the liquid density.Tutor Registration →

Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.