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๐ฌ Think about it
If you watched the Moon every morning for a month and shaded its bright part on paper, you'd see a slow, steady change — full to half to gone, then back again. Like a flipbook of the sky. Let's track it.
How can we track the Moon's changing appearance?
- Begin at sunrise the day after a full Moon.
- Each day, record the date and when the Moon was seen.
- Shade a circle to show the bright portion.
- Note if the bright part is growing or shrinking.
Example:
A diary of shaded circles shows the bright part shrinking a little each day after the full Moon.
In this Activity, we will watch the Moon for a month and record how its bright portion changes.
Materials needed
A notebook, a pencil, a clear view of the sky.
Procedure
1. Spot the Moon at sunrise in the west on the first day after the full Moon.
2. Make a table like Table 11.1 in your notebook.
3. Each day record the date and whether you saw it at sunrise or sunset.
4. Shade a circle to show the bright portion of the Moon.
5. From the second day, note if the bright part is increasing or decreasing.
6. Note whether the Moon looks closer to or farther from the Sun.
7. After about 15 days, switch to observing at sunset for the next 15 days.
2. Make a table like Table 11.1 in your notebook.
3. Each day record the date and whether you saw it at sunrise or sunset.
4. Shade a circle to show the bright portion of the Moon.
5. From the second day, note if the bright part is increasing or decreasing.
6. Note whether the Moon looks closer to or farther from the Sun.
7. After about 15 days, switch to observing at sunset for the next 15 days.
Table 11.1 — Documenting changes in the Moon's appearance
| Day | Date | Moon seen at | Appearance of the Moon in the sky | Size of the bright portion compared to the previous day | Moon and Sun separation in the sky compared to the previous day |
|---|---|---|---|---|---|
| 1. | 16 March 2025 | Sunrise | Full bright circle | — | — |
| 2. | 17 March 2025 | Sunrise | Slightly less than full | Decreased | Closer |
| 3. | 18 March 2025 | Sunrise | Gibbous shape | Decreased | Closer |
Observation
The Moon looks different each day. Its bright portion shrinks after the full Moon, and it appears to move closer to the Sun.
Explanation
The Moon's bright portion and its position in the sky change in a regular, repeating way over the month. These daily changes are the phases of the Moon.
โ Summary
- Moon observed daily
- Bright part shaded
- Change recorded
- Pattern emerges
Important Points
- The Moon is observed daily, starting after a full Moon.
- Its bright portion shrinks, then grows again, over a month.
- The Moon also shifts position relative to the Sun.
Important Definitions
- Phases of the Moon — the changing shapes of the bright portion of the Moon seen from Earth from day to day.
