E. Spatial Sense · Shapes, Maps and Measurement

How Long Does It Take? Seconds, Minutes and Hours

E2.4About 40 minutes

Learning goals

I can describe how long something takes using non-standard units, like claps or songs.
I can tell that seconds are short, minutes are longer, and hours are longer still.
I can choose seconds, minutes or hours to describe how long an event lasts.
I can read the hour hand and minute hand on a clock at o'clock and half past, and find how many hours something took.

Words to know

duration
How long something lasts, from when it starts to when it ends.

second
A very short unit of time. A blink takes less than a second. Clapping slowly, one clap might take about a second.

minute
A longer unit of time. 60 seconds make 1 minute.

hour
A long unit of time. 60 minutes make 1 hour.

half past
30 minutes after the hour. The minute hand points to the 6.

timer
A tool that measures how long something takes, or counts down time.

Which takes longer?

Which takes longer: sneezing, or eating breakfast? Easy! Breakfast takes much longer.

But how much longer? To answer, we measure time. How long something lasts is called its duration.

Measuring time with non-standard units

Just like length, we can measure time with non-standard units:

"Putting on my boots took 20 claps."
"Tidying my room took 2 songs."
"The bath filled in 3 trips around the sand timer."

But claps can be fast or slow, and songs can be long or short. So we also need standard units: seconds, minutes and hours.

Unit	How long?	Something that takes about that long
1 second	very short	saying "one-thousand-one" at a normal speed; one slow clap
1 minute	60 seconds	half the time you should brush your teeth (dentists say to brush for 2 minutes)
1 hour	60 minutes	two half-hour TV shows in a row; a long walk in the park

Benchmarks for seconds, minutes and hours

Remember

60 seconds = 1 minute

60 minutes = 1 hour

A second is the shortest. An hour is the longest.

Worked example

Example 1: Choose the unit

Would you use seconds, minutes or hours to tell how long it takes to (a) sneeze, (b) brush your teeth, (c) sleep at night?

(a) A sneeze is over almost right away. That's seconds.
(b) Brushing your teeth takes about 2 minutes. That's minutes.
(c) Sleeping at night takes most of the night, about 10 hours for many kids. That's hours.

(a) seconds (b) minutes (c) hours

Reading a clock

A clock helps us find out how long things take. An analog clock has two hands:

The short hand is the hour hand. It points to the hour.
The long hand is the minute hand. It shows the minutes.

It takes the minute hand 1 hour (60 minutes) to go all the way around the clock once.

This clock shows 3 o'clock. The short hand points to 3. The long hand points to 12.

When the minute hand points to 12, it is o'clock (exactly on the hour).
When the minute hand points to 6, it is half past (30 minutes after the hour). The hour hand is halfway between two numbers.
A bit extra: when the minute hand points to 3, it is quarter past. When it points to 9, it is quarter to the next hour.

9 o'clock, half past 6, quarter past 2, and quarter to 11.

Worked example

Example 2: How long was the skating party?

A skating party started at 3 o'clock and ended at 5 o'clock. How long did it last?

Start at 3 o'clock.
Count the hours the hour hand moves: 3 to 4 is 1 hour. 4 to 5 is 2 hours.

The party lasted 2 hours.

From 3 o'clock to 5 o'clock is 2 hours.

Worked example

Example 3: Half an hour

Reading time started at 4 o'clock and ended at half past 4. How long was reading time?

At 4 o'clock, the minute hand is at 12.
At half past 4, the minute hand is at 6. It went halfway around the clock.
Halfway around is half an hour, which is 30 minutes.

Reading time lasted 30 minutes (half an hour).

From 4 o'clock to half past 4 is half an hour, or 30 minutes.

Just for fun

What did the hour hand say to the minute hand?

"See you in an hour!" (Every hour, the minute hand zooms all the way around while the hour hand creeps to the next number.)

Hands-on activity

Time detectives

You need: a timer (a kitchen timer, a phone timer with a grown-up's help, or a sand timer) and paper.

How many in 1 minute? Set a timer for 1 minute. How many times can you: hop on one foot? write your name? clap? Guess first, then try!
Seconds count: Count "one-thousand-one, one-thousand-two..." while a grown-up times you with a timer. Does your counting match the real seconds?
Song timer: Time a favourite song. Is it more or less than 3 minutes?
Time diary: Write down when you start and finish 3 things today (like breakfast, a walk, a TV show). Use a clock. Which took the longest? Did any take an hour or more?

Math talk: "Should we say that took 10 seconds, 10 minutes or 10 hours? How do you know?"

Your turn

How many seconds are in 1 minute?

How many minutes are in 1 hour?

Would you measure a soccer game in seconds, minutes or hours?

Would you measure how long it takes to jump once in seconds, minutes or hours?

On a clock, which hand is the hour hand: the short one or the long one?

The minute hand points to 12 and the hour hand points to 7. What time is it?

Lunch started at 12 o'clock and ended at 1 o'clock. How long was lunch?

More practice: warm-up

Which is longer: 1 minute or 1 second?

Which unit is the longest: second, minute or hour?

Name a non-standard unit you could use to time something.

The minute hand points to 6. Is it o'clock or half past?

About how long does it take to tie your shoe: 30 seconds or 30 hours?

More practice: on your own

Swimming lessons start at 10 o'clock and end at half past 10. How long are they?

A movie starts at 2 o'clock and ends at 4 o'clock. How long is the movie?

Eli said, "I brushed my teeth for 2 hours." What unit should he have used?

Put in order from shortest to longest: a school day, a blink, a recess.

Ana counted 25 claps while putting on her snowsuit. Her brother counted 40 claps for the same job. Can you be sure who was faster? Why or why not?

Challenge

Hockey practice started at 5 o'clock and lasted 2 hours. What time did it end?

A bake sale started at 9 o'clock and ended at half past 11. How long did it last?

Mia reads for half an hour, then plays for half an hour. How long is that altogether?

Check your understanding

Quiz

How many minutes are in 1 hour?

Which unit would you use to tell how long a sneeze takes?

Which unit would you use for how long you sleep at night?

The short hand points to 8 and the long hand points to 12. What time is it?

Where does the minute hand point at half past the hour?

A party started at 1 o'clock and ended at 4 o'clock. How long was it?

Why can claps give different answers for the same job?

For parents and teachers

What the curriculum asks: In Grade 2 (expectation E2.4), children use seconds, minutes, hours and non-standard units to describe how long events last. Reading analog clocks to the hour and half hour is included here as a helpful tool for finding durations; quarter past and quarter to are shown as a little extra. Telling time to the minute comes in later grades.

Common difficulties:

Choosing an unreasonable unit ("I brushed my teeth for 2 hours"). Build benchmarks with a timer: time 1 minute of hopping, a song, tooth brushing.
Mixing up the hands. Remember: the short hand tells the hour; the long hand tells the minutes.
Reading half past wrongly. At half past 4, the hour hand is between 4 and 5. Children sometimes read it as 5. It's still 4-something until the minute hand comes back around to 12.
Counting hours: from 3 o'clock to 5 o'clock is 2 hours. Count the jumps (3→4, 4→5), not the numbers.

How to help: Use an analog clock at home and talk about time: "We leave at 4 o'clock. That's in 1 hour." Let your child run a timer during chores and games.