S2 Science: Density And Floating (Paper 2 (intermediate))

S2 Science: Density and Floating (Paper 2 (intermediate))

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 2 (intermediate))

This paper moves to unit conversion, layered liquids, the displaced fraction of floating bodies, and hollow or solid judgement by average density.

Direct answers　For a floating body, write down that displaced weight equals its own weight, then use water at 1 g/cm³ to get the volume. Keep material density apart from average density with cavities, so cutting and hollowing questions are not mixed up.

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)

FoundationA substance has a density of 2 g/cm³. What is it in kg/m³?
FoundationThree immiscible liquids of density 0.8, 1.0 and 1.3 g/cm³ are poured into one jar. What is the order from bottom to top?
FoundationIce has a density of 0.92 g/cm³. Roughly what fraction of a floating iceberg is under water?
IntermediateAn object has a mass of 1.2 kg and a volume of 1 500 cm³. Find its density and whether it floats.
IntermediateA uniform object is cut into two equal halves. What happens to the density of each half?
IntermediateAn iron ball of mass 79 g has a volume of 20 cm³ while iron is 7.9 g/cm³. Is it solid or hollow?
ChallengeA cylinder holding 100 mL rises to 128 mL when a stone is added. What is the volume of the stone?
ChallengeA 200 g block floats on water. How much water does it displace?
ChallengeWhat does a submarine do to dive?
Error redoA student writes a density of 2 cm³/g. What is wrong?

03　Answers and one-line notes

#	Answer	One-line note
1	2 000 kg/m³	One g/cm³ is 1 000 kg/m³, so 2 g/cm³ is 2 000 kg/m³.
2	1.3, then 1.0, then 0.8	The densest settles at the bottom and the least dense floats, so density falls going up.
3	About 92%	The submerged fraction equals the density ratio, 0.92 divided by 1.0.
4	0.8 g/cm³, so it floats	1.2 kg is 1 200 g and 1 200 divided by 1 500 gives 0.8, less than water.
5	It stays the same, because density is a property of the material	Both mass and volume halve, so the quotient does not change.
6	Hollow, because its average density is only 3.95 g/cm³	79 divided by 20 is 3.95, far below 7.9, so there must be empty space inside.
7	28 cm³	The reading rises by 28 mL, which is the volume of water pushed aside.
8	200 g, that is 200 cm³	A floating body displaces its own weight, so 200 g of water, which is 200 cm³.
9	It lets water into its ballast tanks, adding mass	The volume stays the same while mass grows, so its average density exceeds water and it sinks.
10	The fraction is upside down; it should be 2 g/cm³	Density is mass per unit volume, so mass goes on top and volume below.

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.