The short hand goes around the clock twice each day. So 7:00 happens two times: once in the morning and once in the evening. We write a.m. or p.m. to tell them apart. You need Time to Five Minutes for this.
Why it works
A day starts at midnight. The a.m. hours run from midnight to noon: night and morning. The p.m. hours run from noon to midnight: afternoon, evening and night. Noon is 12:00 p.m. and midnight is 12:00 a.m.
| What happens | a.m. or p.m.? |
|---|---|
| Breakfast at 7:30 | a.m. |
| Lunch at 12:15 | p.m. |
| School ends at 3:10 | p.m. |
| Bedtime at 8:00 | p.m. |
Worked example: Crossing noon
A field trip starts at 10:00 a.m. and lasts 3 hours. When does it end?
- Count on one hour at a time: 11:00 a.m., 12:00 noon, 1:00 p.m.
- After noon, a.m. changes to p.m.
Answer: 1:00 p.m.
Key idea
a.m. is from midnight to noon. p.m. is from noon to midnight.
Common mistake
Calling lunch at 12:15 “a.m.” because the hour is 12. Noon starts the p.m. hours, so 12:15 in the daytime is p.m. Check: is it before noon or after?
Grown-up tip: Point out a.m. and p.m. on a phone or an oven clock.