Science 7–10 · Year 7

A month of Moon observations

Science understanding: Earth and space sciences (NSW Stage 4 focus areas Observing the Universe and Data science 1)

PracticalLow risk

The idea

Recording the Moon's shape, direction and time each day reveals the 29.5 day cycle and the Moon rising about 50 minutes later each day, the same lag that moves the tides later each day.

What you need

1 observation sheet with 30 rows: date, time, phase sketch, compass direction, altitude estimate (fist at arm's length is about 10 degrees)
1 magnetic compass or phone compass
1 clear view of the sky; for a daytime Moon a school break time is enough for a fortnight of the month
the Sydney (Fort Denison) tide table for the month, which prints the Moon phase symbols beside the tide heights

How to do it

Start within two days of new Moon (from the phase symbol in the tide table) and record one observation a day at a fixed time when possible.
Sketch the lit shape, record the direction and altitude, and note whether the Moon was seen by day or night.
After 30 days, plot the lit fraction estimate against date and mark the dates of first quarter, full and third quarter.
From the tide table, beside each observation write the day's highest high-tide height and lowest low-tide height, and compute the daily range.
Compare the range around new and full Moon with the range around the quarters.

What you should see

The lit fraction climbs from near zero to full over about 14.8 days and back over the next 14.8, giving a cycle of 29.5 days (NASA gives 29.53 days). The waxing Moon is seen in the afternoon or evening sky and the waning Moon in the morning sky; each day the Moon rises about 50 minutes later. In the July 2025 Fort Denison table the daily range (highest high minus lowest low) is 1.70 m on the new Moon day, 25 July (0.28 m to 1.98 m), and 1.46 m on the full Moon day, 11 July (0.43 m to 1.89 m), against 0.81 m on the first quarter day, 3 July (0.63 m to 1.44 m). The learner knows it worked when the plot shows one smooth rise and fall over the month.

What changes

What you change: date
What you measure: lit fraction, direction and time of visibility
What you keep the same: observation time where possible
observing site

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

The Moon is only visible at night; it is often visible in the daytime sky, most easily in the days around first and third quarter.
The Moon rises at the same time each day; it rises about 50 minutes later each day.

Safety card

Low riskLearners carry it out

Hazards

night observation from home

Controls

observe from a yard or window with an adult aware
no observation near roads

Note

No hazardous chemical and no flame or heating apparatus: a generic classroom risk assessment (CSIS 1.7 or RiskAssess) covers trips, spills, warm lamps and sharp edges.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Science 7-10 Syllabus (2023), NSW Education Standards Authority (implemented from 2026; codes read at curriculum.nsw.edu.au on 22 and 23 September 2026)SC4-OTU-01 SC4-DA1-01 SC4-WS-01 SC4-WS-05 SC4-WS-06
Australian Curriculum v9AC9S7U03AC9S7I03AC9S7I05

Sources

The pages the author read to write this activity.

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