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Primary General Studies: Earth, Moon and Sun (Paper 3 (challenge))
Primary General Studies: Earth, Moon and Sun (Paper 3 (challenge))
This paper deals with the positions of the three bodies plus harder speed and period calculations, with units and rounding stated.
Direct answers Decide which body is in the middle first, then calculate, and finish by stating the required rounding.
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: Earth, Moon and Sun |
| Level | P5 |
02 Questions (10 items)
- FoundationDuring which phase can a solar eclipse happen?
- FoundationDuring which phase can a lunar eclipse happen?
- FoundationAbout how many degrees is the axis of Earth tilted from the vertical?
- IntermediateIf Earth spins once a day, how many spins are there in a 365 day year?
- IntermediateAbout how many Earth days does the Moon take to spin once?
- IntermediateThere are usually two high tides a day. About how far apart are they?
- ChallengeOne lunar orbit takes 27.3 days. How many days are there in 13 orbits, to one decimal place?
- ChallengeThe equator is about 40,075 km around and Earth spins once in 24 hours. About how far does a point on the equator move each hour, to the nearest km?
- ChallengeThe Moon orbits Earth every 27.3 days. How many complete orbits are there in 365 days, to the nearest whole number?
- Error redoA classmate says that during a lunar eclipse the Moon is between the Sun and Earth. What is correct?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | At new moon. | At new moon the Moon sits between the Sun and Earth, and only then can the three line up for a solar eclipse. |
| 2 | At full moon. | At full moon Earth lies between the Sun and the Moon, so the shadow of Earth can fall on the Moon. |
| 3 | About 23.5 degrees. | The 23.5 degree tilt makes the sunlight angle change through the year, which gives us the seasons. |
| 4 | 365 spins. | Each spin is one day, so the number of spins equals the number of days. |
| 5 | About 27.3 Earth days. | Its spin and its orbit take the same time, an effect called synchronous rotation. |
| 6 | About 12 hours 25 minutes, which is 745 minutes. | 12 times 60 plus 25 gives 745 minutes, which is why tide times shift each day. |
| 7 | 354.9 days. | 27.3 times 13 is 354.9, about ten days short of a year, which is why lunar calendars add leap months. |
| 8 | About 1,670 km. | 40,075 divided by 24 is about 1,670, so a person on the equator is moving very fast indeed. |
| 9 | About 13 orbits. | 365 divided by 27.3 is about 13.4, so 13 complete orbits fit in a year. |
| 10 | In a lunar eclipse Earth is between the Sun and the Moon; the Moon in the middle gives a solar eclipse. | The order of the three bodies decides which eclipse happens, so remember which one sits in the middle. |
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.
A spin of about 24 hours gives day and night while a 365 day orbit with a 23.5 degree tilt gives the seasons, and eclipses happen at new moon or full moon.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.