Minds On

Time for telling time

Explore the following MathXplosion video, “Actually, It’s an Estimate.”

Using a method of your choice, record your thinking about:

  • the words Eric used to describe time
  • the tools you could use to measure and track time

Action

Telling time with digital clocks

A digital clock and a digital watch both showing the time 12:40.

Digital clocks can be wrist watches, alarm clocks, or radio clocks.

Digital clocks display time using numbers. These types of clocks use a colon between hours and minutes to show the time.

A digital clock showing a 7 (labelled hours), a colon, and a 15 (labelled minutes).

There are 60 minutes in one hour.

The following digital clock shows the time 10:59.

What will the time be after one more minute passes?

A digital clock showing the time 10:59.

When you are ready, press the “Answer” button to reveal the time after one more minute passes.

60 minutes have passed since ten o’clock. The time is now eleven o’clock.

We use the term “o’clock” when the time is exactly on the hour.

A digital clock showing the time 11 o’clock.

There are 24 hours in a day, but a day is split into morning and afternoon.

There are 12 hours in the morning and 12 hours in the afternoon.

Clocks use a.m. to show a morning time and p.m. to show a time in the afternoon.

For example, the following clock displays the time 11:00 a.m. This means it is 11 in the morning.

A digital clock showing the time 11 a.m. This means it is 11 in the morning.

Most clocks show just hours and minutes, but some add another colon to show seconds.

For example, the following clock shows that it is 10:30, but it also shows that 30 seconds have passed. So, the time is 10:30 and 30 seconds.

A digital clock showing the time 10 30 30. This means it is 10:30 and 30 seconds.

The 24-hour-clock

Many parts of the world use the 24-hour clock to display time.

The 24-hour clock is often used in bus, train or airplane timetables, and in the military.

For example, the following 24-hour clock displays the time 23:59:59. In one more second, it will read 00:00:00 and be the start of a new day.

A digital clock showing the time 23 59 59, or 23:59:59.

The 24-hour clock does not use a.m. and p.m. since it counts time from midnight to midnight.

Test Your Skills!

Write some solutions

Respond to the following questions. You can record your thinking digitally, orally, or in print.

  • What time would 1:00 p.m. be equal to on a 24-hour clock?
  • What mental math do you need to do to find the correct 24-hour time for p.m. times?
  • What time would 9:00 a.m. be equal to on a 24-hour clock?

When you are ready, press each question to reveal the answers.

1:00 p.m. would be 13:00 on a 24-hour clock

You need to add the time to 12.

9:00 a.m. would be 09:00 on a 24-hour clock.

Fill in the blank

In this activity, you will be given some times from a 24-hour clock. Your task is to fill in the blanks to change the time to a.m. or p.m. time.

Here is an example:

23:45 = (Blank)

The correct answer is:

23:45 = 11:45 p.m.

Now it’s your turn!

For each blank, select the corresponding time from the drop-down menu.

Timers

A watch with a timer counting down from 30 seconds.

A timer counts down to zero. Timers are used to know when a certain amount of time has passed. Setting a timer can be used to:

  • remind a baker to turn off an oven after a certain amount of time
  • help an athlete train for a certain amount of time
  • share a device or toy after having a turn for certain amount of time

Can you think of other reasons to use a timer?

Analog clocks

Analog clocks are another tool used to tell time. They use three scales to display the time: hours, minutes, and seconds.

Hours on an analog clock

Hours are measured from 0 to 12.

Most analog clocks have a round “face” with the numbers 1 to 12 spread out along the edge. These numbers represent hours.

The following image displays an analog clock face with the hours shown. There are also 4 short lines in between each hour.

Analog clock face. It is a circle with the numbers 1 to 12 along the outside. There are 4 short ticks between each number.

Minutes on an analog clock

Minutes are measured from 0 to 60.

Minutes are sometimes shown with small lines between every hour.

If an analog clock had a number for every minute, it would be like the following image.

Analog clock face. It is a circle with the numbers 1 to 12 along the outside and the numbers 1 to 00 for each second.

Seconds on an analog clock

Seconds are measured using 0 to 60, just like minutes.

The hands of an analog clock

Analog clocks have two or three hands. Hands on a clock are like arrows. As time passes, they point to the current hour, minute, and sometimes, second.

The hour hand is the shortest and points to the hour.

The minute hand is longer and tells us the minutes.

Some clocks also have another hand that tells us the seconds. The second hand is the longest hand and is often thin and red.

The second hand moves every second.

The following image displays an analog clock with an hour hand, minute hand, and second hand.

An analog clock with an hour hand, minute hand, and second hand.

Benchmarks

When telling times, we use benchmarks, which is when the minute hand lines up on multiples of five minutes. Some benchmarks get special names.

Explore the following image, which displays benchmarks. Consider what each of the benchmarks represent.

An analog clock with numbers 1 to 12 along the outside marked at every 5 minutes, with 1 being 5 past the hour, 2 being 10 past the hour, and continuing to 12.

Analog clocks use fractions of a circle to show the following benchmark times:

  • quarter past the hour means 15 minutes have past
  • half past the hour means 30 minutes have past
  • quarter to the hour means there are 15 minutes until another hour
Three analog clocks. The first is shaded to show 15 minutes. The second, 30 minutes. The third, 15 minutes until the next hour.

Time matching

Let’s practice what we’ve learned about telling time. Match each digital clock to the time it is displaying.

Let’s try some more, this time with analog clocks. Match each analog clock to the time it is displaying.

Brainstorm

Reflect

Respond to the following questions. You can record your thinking using a method of your choice.

  • Which times were easiest to match on the analog clock?
  • Which times were more difficult to match as a digital time with a colon?

Consolidation

Time teller

The following image indicates 12 o’clock in words, on a digital clock, and on an analog clock.

A digital clock and analog clock both showing 12:00.

Now it’s your turn.

Record the words, analog, and digital displays for 5 different times of your choosing. Make sure you include at least one:

  • quarter past
  • half past
  • quarter to
  • o’clock
  • time with an odd number of minutes

You can record your times using the following fillable and printable Time Teller document. You can also complete this activity in your notebook or using another method of your choice.

A 3-column chart. The first column is time in words. The second column is digital display. The third column is analog display.

Press the Activity button to access Time Teller.

Activity (Open PDF in a new tab)

Think about your learning

  • Why is it important to know how to tell time from analog and digital clocks?

Reflection

How do you feel about what you have learned in this activity? Which of the next four sentences best matches how you are feeling about your learning? Press the button that is beside this sentence.

I feel...

Now, record your ideas about your feelings using a voice recorder, speech-to-text, or writing tool.