S3 Science: Earth, Moon And The Solar System (Paper 3 (challenge))

S3 Science: Earth, Moon and the Solar System (Paper 3 (challenge))

2026-11-14

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Tutor Prep Guide · Rotation and revolution of the Earth, day and night, seasons and the 23.5 degree tilt, the orbit of the Moon and its phases, solar and lunar eclipses, tides, the order of the eight planets and the scale of the solar system

S3 Science: Earth, Moon and the Solar System (Paper 3 (challenge))

This paper deals with synchronous rotation, the share of the mass in the Sun, the light year, the tilt of the axis and the seasons, the composition of inner and outer planets, the tidal pull, and the distances and light travel times to Neptune and Mars.

Direct answers　Synchronous rotation takes 27.3 days; the Sun holds 99.8 percent of the mass; a light year is 9.46 times 10 to the power 12 km; the 23.5 degree tilt causes the seasons; inner planets are rocky and outer planets gassy and icy; sunlight reaches Neptune in 250 minutes and Mars is 228 million km away.

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: S3 Science: Earth, Moon and the Solar System
Level	S3

02　Questions (10 items)

FoundationWhy does the Moon always show the same face to the Earth?
FoundationWhat share of the mass of the solar system is in the Sun and where is most of the rest?
FoundationHow many kilometres are there in a light year and is it a time or a distance unit?
IntermediateBy how many degrees is the Earth axis tilted and what does the tilt cause?
IntermediateHow do the compositions of the inner and outer planets differ?
IntermediateThe Moon is much less massive than the Earth, so why does it still raise clear tides?
ChallengeNeptune is about 30 AU from the Sun, so how many minutes does sunlight take to reach it?
ChallengeMars is 1.52 AU from the Sun, so what is that distance in kilometres?
ChallengeWhy is the surface temperature of the Moon so extreme?
Error redo“The seasons are caused by the changing distance between the Earth and the Sun.” What is wrong?

03　Answers and one-line notes

#	Answer	One-line note
1	Its rotation period equals its orbital period, about 27.3 days, which is called synchronous rotation	That is why the far side is never seen from the Earth and is photographed only by spacecraft.
2	About 99.8 percent, and most of the rest is in Jupiter	That is why the motion of the planets is governed mainly by the gravity of the Sun.
3	About 9.46 times 10 to the power 12 km, and it is a distance unit	A light year is the distance light travels in a year, not a length of time.
4	23.5 degrees, which causes the seasons and the change in day length	The direction of the tilt stays fixed during the orbit, so each hemisphere leans towards the Sun in turn.
5	The inner four are rocky while the outer four are made mainly of gas and ice and have lower density	It is too hot near the Sun for volatile material to stay on an inner planet.
6	It is close to the Earth and water can flow, so the difference in its pull is enough to raise the tide	The pull of the Sun is about 45 percent of that of the Moon but it is far more distant.
7	About 250 minutes	30 times 500 seconds gives 15000 seconds, then divide by 60.
8	About 228 million km	1.52 times 150 million km gives 228 million km.
9	The Moon has no atmosphere, so it cannot hold heat or move it by convection	With no atmosphere meteoroids are not burned up, so impact craters stay for a very long time.
10	The main cause is the 23.5 degree tilt of the axis, while the change in distance is small	The seasons being opposite in the two hemispheres shows that the tilt, not the distance, is the key.

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.

For Earth and Moon questions ask three things: whether rotation or revolution causes the effect, which body stands in the middle, and whether the answer should be an angle, a time or a distance.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.