Measurement & Data
Understanding Length and Time
Grade 1
- ✓Order three objects by length from shortest to longest or longest to shortest.
- ✓Compare the lengths of two objects using terms like 'longer' and 'shorter.'
- ✓Identify the hour hand and minute hand on an analog clock.
- ✓Tell time to the hour using an analog clock.
- ✓Tell time to the half hour using an analog clock.
Key concepts
Length tells us how long something is. We can compare objects to see which one is longer or shorter. When we order objects by length, we put them in a line from the shortest to the longest, or from the longest to the shortest.
An analog clock is a clock with hands that move around a face to show the time. It usually has numbers from 1 to 12. There are two main hands: the hour hand and the minute hand.
The hour hand is the shorter hand on an analog clock. It points to the hour. It moves slowly around the clock face.
The minute hand is the longer hand on an analog clock. It points to the minutes. When it points to the 12, it means it's the start of a new hour. When it points to the 6, it means half an hour has passed.
When the minute hand points exactly to the 12, it means it is a new hour. We say 'o'clock.' The hour hand will point directly at the number for that hour.
When the minute hand points exactly to the 6, it means half an hour has passed since the last hour. We say 'half past' the hour. The hour hand will be halfway between the number of the hour that just passed and the next hour.
Key facts to remember
- 1Length tells us how long an object is.
- 2We can compare objects using 'longer than' and 'shorter than' to order them.
- 3An analog clock has two main hands: a shorter hour hand and a longer minute hand.
- 4When the minute hand points to the 12, it is 'o'clock.'
- 5When the minute hand points to the 6, it is 'half past' the hour.
- 6The hour hand points directly at the hour for 'o'clock' times.
- 7The hour hand is halfway between two numbers for 'half past' times.
Worked examples
Example 1
Order these three ribbons from shortest to longest:
Answer
Ribbon C (shortest), Ribbon A (middle), Ribbon B (longest)
Imagine you have three ribbons: Ribbon A is 5 inches, Ribbon B is 7 inches, and Ribbon C is 3 inches. You would visually compare them.
Example 2
What time is shown on the analog clock if the hour hand is pointing to the 4 and the minute hand is pointing to the 12?
Answer
4 o'clock
Remember, the minute hand on the 12 always means 'o'clock'.
Example 3
What time is shown on the analog clock if the hour hand is between the 9 and the 10, and the minute hand is pointing to the 6?
Answer
Half past 9
For 'half past,' the hour hand will always be between two numbers. You say the number it just passed.
Common mistakes
- ✗Confusing the hour hand (shorter) with the minute hand (longer) on an analog clock.
- ✗Reading the hour incorrectly for 'half past' times, especially when the hour hand is between two numbers (e.g., saying 'half past 8' when it's 'half past 7' because the hand is closer to the 8).
- ✗Not understanding that the minute hand pointing to the 6 means 'half past' and not '6 minutes.'
- ✗Incorrectly ordering objects by length, especially when objects are very similar in size.
Exam tips
- ★Always look carefully at both the hour hand and the minute hand when telling time.
- ★For 'o'clock' times, make sure the minute hand is exactly on the 12.
- ★For 'half past' times, make sure the minute hand is exactly on the 6, and remember to use the hour that the hour hand has *just passed*.
- ★When ordering objects by length, take your time to compare each object to the others.
Ready to practise?
Try a problem on this topic
Snap a photo or type a question — get step-by-step working instantly.