Primary General Studies: The Solar System And The Movement Of The Earth (Paper 3 (challenge))

Primary General Studies: The Solar System and the Movement of the Earth (Paper 3 (challenge))

2026-11-13

Tutor Prep Guide · rotation and revolution, planet order, moon phases and the cause of seasons

Primary General Studies: The Solar System and the Movement of the Earth (Paper 3 (challenge))

Paper three chains the steps: hours to degrees, longitude to time zones, light speed to seconds, then shadows and daylight explain the seasons.

Direct answers　On any two-step question write the middle number first, then substitute, and only put the units at the end.

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: Primary General Studies: The Solar System and the Movement of the Earth
Level	parts of a closed circuit, conductors against insulators, series against parallel, adding up battery voltage, and electrical safety

02　Questions (10 items)

FoundationThrough how many degrees does the Earth turn in three hours?
FoundationTwo places differ by 90 degrees of longitude. How many hours apart are they?
FoundationHong Kong is 8 hours ahead of London. When it is 8 pm in Hong Kong, what time is it in London?
IntermediateThe Moon is about 384,400 km away and light travels 300,000 km a second. How long does moonlight take to arrive?
IntermediateA year has 365 days and one cycle of moon phases lasts 29.5 days. How many whole cycles fit in a year?
IntermediateThe equator is about 40,000 km round and the Earth turns once a day. How fast does the ground at the equator move each hour?
ChallengeAn orbit takes 365 days. How long is half a year?
ChallengeOn a sunny day, when is a shadow shortest?
ChallengeWhy are summer days so long in the northern hemisphere?
Error redoError clinic: “Seasons happen because the Earth is sometimes nearer the Sun.” Why is that inaccurate?

03　Answers and one-line notes

#	Answer	One-line note
1	45 degrees.	At 15 degrees an hour, 15 × 3 = 45.
2	Six hours.	Every 15 degrees is one hour, so 90 ÷ 15 = 6 hours.
3	Noon, 12 pm.	20 minus 8 is 12, so London is still at midday.
4	About 1.28 seconds.	384,400 ÷ 300,000 is about 1.28, so we see the Moon as it was 1.28 seconds ago.
5	About 12.	365 ÷ 29.5 is about 12.37, so 12 whole cycles fit, which is why a year has twelve months.
6	About 1,666.7 km per hour.	40,000 ÷ 24 is about 1,666.7, faster than any airliner.
7	182.5 days.	365 ÷ 2 = 182.5, half of the yearly circuit and half of the seasons.
8	Around noon, when the Sun is highest.	The higher the Sun, the closer the light is to vertical and the shorter the shadow.
9	The tilt of the axis combined with the Earth going round the Sun.	In summer the northern half leans towards the Sun, so it stays in sunlight longer.
10	The main cause is the tilted axis, not the small change in distance.	If distance were the cause, both hemispheres would have summer together, but their seasons are opposite.

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.

Paper four clears the conductor, insulator and battery direction misconceptions.Tutor Registration →

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