S2 Science: Density And Floating (Paper 1 (basics))

S2 Science: Density and Floating (Paper 1 (basics))

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 1 (basics))

This paper drills the basics: the density formula in three directions, the displacement method, and deciding floating by comparing with water.

Direct answers　Write down the mass and volume first, then use the density formula; floating needs only a density comparison.

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 density?
FoundationA metal block has a mass of 100 g and a volume of 50 cm³. What is its density?
FoundationHow is the volume of an irregular stone measured?
IntermediateA piece of wood has a mass of 240 g and a volume of 80 cm³. What is its density?
IntermediateA liquid has a density of 2.5 g/cm³. What is the mass of 40 cm³ of it?
IntermediateA substance has a density of 0.8 g/cm³ and a mass of 200 g. What is its volume?
ChallengeA block of density 0.6 g/cm³ is put in water of density 1 g/cm³. Does it float or sink?
ChallengeAn iron block of density 7.9 g/cm³ is put in water. Does it float or sink?
ChallengeA cylinder reads 50 mL and 68 mL after a stone is put in. What is the volume of the stone?
Error redoA student says an object with a larger density must be heavier. Is that right?

03　Answers and one-line notes

#	Answer	One-line note
1	The mass per unit volume, usually in g/cm³	Density links mass and volume; for one substance it is fixed and does not depend on size.
2	2 g/cm³	Density equals 100 divided by 50, that is 2 g/cm³.
3	By displacement: compare the cylinder reading before and after the stone is added	An irregular shape cannot be measured with a ruler, so the rise in the water level gives the volume.
4	3 g/cm³	240 divided by 80 is 3 g/cm³, which is denser than water so it sinks.
5	100 g	Mass equals 2.5 times 40, that is 100 g.
6	250 cm³	Volume equals 200 divided by 0.8, that is 250 cm³.
7	It floats, because 0.6 is less than 1	An object floats when its density is lower than the liquid, and part of it shows above the surface.
8	It sinks, because iron is much denser than water	Iron at 7.9 is far denser than water at 1, so its weight beats the upthrust and it sinks.
9	18 cm³	The volume is 68 minus 50, that is 18 cm³, since 1 mL is 1 cm³.
10	No, the volume matters too, since mass is density times volume	A small iron piece is lighter than a big log, so density alone cannot decide the mass.

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.