Coaching Centre
The Earth, Sun and Moon review
A summary of the whole Earth, Sun and Moon chapter, key words, and a mixed test covering day and night, seasons, Moon phases, tides, eclipses, models of the solar system, scale, Aboriginal and Torres Strait Islander astronomy and space technology.
Use this page to check the whole chapter. Read the summary, make sure you can explain every key word, then do the test without looking back.
Chapter summary
| Topic | What you need to know |
|---|---|
| 6A Day, night and the seasons | Rotation (24 h) gives day and night; revolution (365¼ days) gives a year. The 23.4° tilt causes seasons: higher Sun and longer days in the hemisphere tilted towards the Sun. Solstices, equinoxes, leap years. |
| 6B The Moon and its phases | Moonlight is reflected sunlight. Half the Moon is always lit; phases show how much of that half faces us. 29.5-day cycle. Same face always visible (synchronous rotation). From Australia, waxing is lit on the left. |
| 6C Tides | The Moon's gravity makes two bulges; two high tides about every 24 h 50 min. Spring tides at new and full moon (Sun and Moon in line); neap tides at the quarters. |
| 6D Eclipses | Solar: Sun–Moon–Earth, new moon, umbra (total) and penumbra (partial), never look directly. Lunar: Sun–Earth–Moon, full moon, Moon turns red. Not monthly because the Moon's orbit is tilted 5°. |
| 6E Models of the solar system | Contributions from many cultures. Geocentric (Ptolemy, epicycles) replaced by heliocentric (Copernicus) after evidence from Tycho, Kepler (ellipses), Galileo (Jupiter's moons, phases of Venus) and Newton (gravity). |
| 6F The solar system to scale | Sun, 4 rocky and 4 giant planets, dwarf planets, asteroids, comets. 1 AU = 150 million km; light-year for star distances. Mostly empty space. |
| 6G Aboriginal and Torres Strait Islander astronomy | Tens of thousands of years of observation used for calendars, food and navigation: Emu in the Sky, Tagai, Seven Sisters, Moon and tides. Knowledge belongs to many nations; some is restricted. |
| 6H Exploring space | Refracting and reflecting telescopes, radio telescopes, the electromagnetic spectrum, spectroscopes and spectral lines, Hubble and Webb, the Space Race, probes, rovers, satellites, the ISS. |
Key words
astronomical unit · axis · dwarf planet · eclipse · electromagnetic spectrum · ellipse · emission spectrum · epicycle · equinox · full moon · geocentric · gibbous · gravity · heliocentric · leap year · light-year · lunar · neap tide · new moon · orbit · penumbra · phase · probe · reflecting telescope · refracting telescope · retrograde motion · revolution · rotation · satellite · solar · solstice · spectroscope · spring tide · synchronous rotation · umbra · waning · waxing
Test yourself
One rotation of the Earth takes
That's one day.
In June, Sydney has short days and a low noon Sun because
Tilt, not distance.
A full moon rises at about
It's opposite the Sun in the sky.
Which combination gives a spring tide?
Sun, Earth and Moon in a line.
A total solar eclipse is seen by people in the
All of the Sun is blocked in the umbra.
Galileo's observation of a full set of phases of Venus supported
Venus can only show all phases if it orbits the Sun.
Neptune is 30 AU from the Sun. This means it is
1 AU is the Earth–Sun distance.
Dark lines in a star's spectrum show
Each element has its own pattern of lines.
Label the eclipses.
What causes it?
The Earth's causes the seasons. The Moon's phases repeat every days. A eclipse happens at full moon. A Sun-centred model is called . The average Earth–Sun distance is one astronomical .
On one night, a student in Sydney sees a full moon turn a dull red over about an hour. Two weeks later, the student's cousin in Queensland sees the Sun disappear for two minutes in the middle of the day. Name and explain both events, including the positions of the Sun, Earth and Moon, the phase of the Moon, and why the second event was not seen in Sydney.
The first event was a total lunar eclipse. The Sun, Earth and Moon were in a line with the Earth in the middle, at full moon, so the Moon passed into the Earth's shadow. It turned red because sunlight passing through Earth's atmosphere is bent towards the Moon and the red light gets through. The second was a total solar eclipse: two weeks later the Moon had moved half way around its orbit to new moon, and this time the Moon was between the Sun and the Earth. Its dark central shadow, the umbra, fell on part of Queensland. The umbra is only a few hundred kilometres wide, so only people inside it saw the Sun completely covered; Sydney was outside it and would have seen at most a partial eclipse.