Lesson 5 of 13
They do not divide
Show on a big screenA Moon month is one round of the Moon's phases. Do twelve Moon months fit one year?
Step 1 of 3
- A solar year, one trip round the Sun, is 365 days.
- Twelve Moon months make 354 days.
- The gap is nearly 11 days.
The rule
No, they do not fit. A Moon month is about 29.5 days. So 12 × 29.5 = 354 days.
Twelve Moon months make 354 days. A solar year is about 365 days. So twelve Moon months fall short by nearly 11 days.
A lunar calendar counts Moon months. It does not match the seasons. The gap grows about 11 days each year. After 3 years, 3 × 11 = 33 days. That is more than one month.
Slide the years. Watch the gap grow.
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Try the lab to finish this lesson.