AM and PM

For Elementary Students

What Do AM and PM Mean?

AM and PM help us know if a time is in the morning or the afternoon/evening.

Think about it like this: There are two 3 o'clocks each day — one in the middle of the night/morning, and one in the afternoon. AM and PM tell us which one!

AM = Morning (Before Noon)

AM stands for "ante meridiem" (Latin for "before noon").

AM times are from midnight to noon (12:00 in the middle of the day).

Examples of AM:

• 7:00 AM → morning (breakfast time)
• 9:00 AM → morning (school starts)
• 11:30 AM → late morning (almost lunch)

Remember: If the sun is rising or it's before lunch, it's AM.

PM = Afternoon and Evening (After Noon)

PM stands for "post meridiem" (Latin for "after noon").

PM times are from noon to midnight (12:00 in the middle of the night).

Examples of PM:

• 12:30 PM → afternoon (after lunch)
• 3:00 PM → afternoon (school ends)
• 7:00 PM → evening (dinner time)
• 9:00 PM → night (bedtime for many kids)

Remember: If the sun is setting or it's after lunch, it's PM.

The Two 12 O'Clocks

There are two times when the clock shows 12:00:

12:00 AM = Midnight (middle of the night, start of a new day)

12:00 PM = Noon (middle of the day, lunchtime)

Tip: Noon sounds like "aftrenoon," so noon is PM.

Telling AM from PM

Ask yourself: What am I doing at this time?

3:00 — Am I eating breakfast (AM) or coming home from school (PM)?

8:00 — Am I waking up (AM) or getting ready for bed (PM)?

For Junior High Students

The 12-Hour Clock

We use a 12-hour clock in everyday life, where:

• The clock goes from 12 to 11, then starts over at 12 again
• We use AM for the first 12 hours (midnight to noon)
• We use PM for the second 12 hours (noon to midnight)

How AM and PM Work Throughout the Day

Converting PM to 24-Hour Time

Many countries use 24-hour time (also called military time), where:

• AM times stay the same (1:00 AM = 01:00)
• PM times add 12 (1:00 PM = 13:00, 3:00 PM = 15:00)

Examples:

Rule for PM: Add 12 to the hour (except 12:00 PM stays 12:00).

Example: 6:00 PM → 6 + 12 = 18:00 in 24-hour time

We will learn more about 24-hour time later.

Elapsed Time Across AM/PM

Example: How much time from 10:30 AM to 2:30 PM?

Method 1: Count the hours

• 10:30 AM → 11:30 AM (1 hour)
• 11:30 AM → 12:30 PM (1 hour, crossing into PM)
• 12:30 PM → 2:30 PM (2 hours)
• Total: 4 hours

Method 2: Think about noon as a marker

• 10:30 AM to 12:00 PM = 1½ hours
• 12:00 PM to 2:30 PM = 2½ hours
• Total: 1½ + 2½ = 4 hours

Common Mistakes

❌ "12:00 AM is noon" — No! 12:00 AM is midnight, 12:00 PM is noon

❌ Forgetting to write AM/PM — 3:00 could mean morning or afternoon!

❌ Saying "12:00 PM in the morning" — That's a contradiction. 12:00 PM is noon (afternoon).

Real-Life Uses

Schedules: "The movie starts at 7:30 PM."

Appointments: "Your dentist appointment is at 9:00 AM."

TV Guides: "The show airs at 8:00 PM."

Transportation: "The bus leaves at 6:45 AM."

International Differences

• United States — mostly uses 12-hour time with AM/PM
• Many other countries — use 24-hour time (no AM/PM needed)
• Both are correct, just different systems!

Practice