### Video Transcript

Reading Clocks: Time to the Half
Hour

In this video, we’re going to learn
how to tell time to the half hour using analog and also digital clocks. We know that an analog clock has a
clock face and two hands that show the number of minutes and hours that have gone
by.

Every new hour begins with an
o’clock time. This is when the minute hand is
pointing to the number at the top of the clock face, the number 12. You know, we can think of the
numbers that go all the way around the clock as being a little bit like a curved
number line. And when the minute hand points to
12 at an o’clock time, it’s almost like that minute hand is at the start of the
number line ready to go all the way around the clock again.

The hour hand, which is the shorter
hand, points to the hour of the day that it is. Here, we can see it’s pointing
exactly to the number four. And that’s why when we see a clock
that looks like this, we can read it as 4 o’clock.

But what happens to the two hands
of the clock now? The minute hand will slowly make
its way around the clock face. Can you see the little marks around
the outside? Each one is worth one minute. And so, with each minute that goes
by, the minute hand moves another notch.

But meanwhile, what’s the hour hand
doing? It’s not pointing directly to the
number four anymore. It’s moved. But the hour hand moves so slowly
we often don’t even notice it moves. Did you know it’d moved? The hour hand moves so slowly that
a whole hour needs to go by from it pointing to the number four at 4 o’clock to
pointing to the number five at 5 o’clock.

Now, we already know about o’clock
times, but in this video, we’re going to be telling time to the half hour. So, that includes times called
half-past times as well. What do you think a half-past time
looks like? Let’s speed up time until we get
there. This is what we call a half-past
time. Let’s think about the long minute
hand to begin with. It was pointing straight up to the
12 at 4 o’clock, but now it’s traveled half the way around the clock face. Instead of pointing straight up,
it’s pointing straight down.

When the minute hand, that’s the
long hand, points directly to the number six, we know that it’s traveled half the
way around the clock and it’s a half-past time. But how would we read this
time? Half past what? We need to look at the hour hand to
work out this. Where would you say the hour hand
is pointing now? It’s moved on from pointing to the
four, and it certainly hasn’t reached the number five yet. It’s halfway between the four and
the five. You could think of it as moving
halfway past the number four. And so, we could read this time as
half past 4.

Now, what about the other sort of
clock? You might see it at school or in
your house. What does a half-past time look
like on a digital clock? Remember that digital times are
made out of digits. They often have two dots or
squares, which we can call a colon, to separate the digits that show the number of
hours from the digits that show the number of minutes. Let’s stick with our time of half
past four. What might that look like on a
digital clock?

We know that four o’clock looks
like this. Can you see the two zeros? Remember that these tell us the
number of minutes. Cause we’re starting a new hour,
we’re starting from zero again. So, any digital time that ends in
two zeros is an o’clock time. But let’s change our zeros to
question marks because we need to think about how many minutes have gone by at a
half-past time.

What will our digital clock look
like at half past 4? To help us, we can think about the
number of minutes that there are in a whole hour. And this is where our analog clock
comes in useful. We know that the gap between one
number and the next number on a clock face is worth five minutes. If we look carefully, we can see
five little intervals between the two numbers, can’t we? And we can use this fact to skip
count in fives really quickly around the clock face to find out how many minutes
there are in a whole hour.

Five, 10, 15, 20, 25, 30. Let’s pause here for a moment. This is interesting. Remember, the whole point of what
we’re doing here is trying to find out how many minutes there are in half an
hour. Now, we’ve gone half the way around
the clock, and it looks like there are 30 minutes in half an hour. Let’s carry on counting all the way
to a full hour, and then we’ll be able to see whether we’re right. 35, 40, 45, 50, 55, 60. A whole hour is 60 minutes. And because we know that 30 and 30
make 60, we know that half an hour is 30 minutes.

And because 30 minutes have gone by
at half past 4, our digital time will look like this. 4:30 is another way of saying half
past 4. 5:30 is the same as half past
5. 6:30 is half past 6, and so on. The clues that tell us that these
are half-past times are the minute hand pointing straight downwards to the number
six and on our digital clock, it’s these digits here that show us that 30 minutes
have gone by. Let’s try answering some questions
now where we have to read the time to the half hour on these two different types of
clocks.

Which of the following digital
clocks displays the time half past 4?

To help us answer this question,
we’re shown three digital clocks to choose from. These are clocks that show the time
of the day using digits. In a digital time, we have one or
two digits that represent the number of hours, followed by two dots, and then two
digits after the dots that tell us the number of minutes that have gone by. Now, the time we’re looking for
here is half past 4. Which of our three digital clocks
shows the time half past 4?

We know that for the minute hand on
a clock to make a whole turn all the way around, takes 60 minutes. One whole hour is worth 60
minutes. Now, if the minute hand is only
turned half the way around the clock, half an hour has gone by. It’s a half-past time. And because half of 60 is 30, we
know that half of an hour is the same as 30 minutes. So, if we are looking for a digital
time that shows a half-past time, the minutes part of our digital clocks should show
a three and a zero, the number 30.

But wait a moment, if we look at
our three digital clocks, we can see that they all show the number 30. They’re all showing half-past
times. We’ve got 3:30, 4:30, and 5:30. We’re going to need to think
carefully about the number that we want in the hour place. We need to find the time half past
four. And so, we’re looking for a digital
clock where there’s a four in the hours place.

There are 30 minutes in half an
hour. And so, we know at a half-past
time, the number of minutes that are shown on a digital clock is going to be 30. The digital clock that shows the
time half past 4 is the one that shows 4:30.

Pick the time shown by the
clock. 8 o’clock, 9:30, or 8:30.

In this question, we’ve got times
that are shown in two different ways. On this analog clock, which is
where we have a clock face and two hands that help us to tell the time. And then, we have three times to
choose from that have been written as digital times. This is where we write the time
using digits and we use two dots to separate the number of hours from the number of
minutes. We need to pick the digital time
that matches the analog clock.

So, to begin with, let’s read the
time on this analog clock. First of all, where is the minute
hand pointing? The minute hand is the long hand,
isn’t it? And we can see that it’s pointing
downwards to the number six. We know that whenever there’s an
o’clock time, the minute hand points straight up at the number 12. And so, we can see how far this
minute hand has moved, can’t we? It started pointing up to 12, and
it’s making its way around the clock. It’s gone half the way around the
clock.

And so, we know whenever the minute
hand points to the number six, it’s going to be what we call a half-past time. But half past what? To answer this question, we need to
look at what the hour hand is doing. We can see the hour hand, that’s
the shorter hand, is pointing in between the numbers eight and nine on the clock
face. And if we look closely, it’s not
pointing any position in between, it’s halfway in between. Can you see that?

So, would you say the time is half
past eight or half past nine? From what we know about o’clock
times, we know that at 8 o’clock, the hour hand must have been pointing to the
number eight. And at 9 o’clock, it’s going to be
pointing at the number nine. But it hasn’t got there yet. In fact, we could say that the hour
hand has gone half way past the number eight. And that’s how we know that it’s
half past 8.

Now, which of our three digital
times shows half past 8? The first number before the two
dots in a digital time shows us the number of hours that have gone by. So, if we are looking for the time
half past 8, we need a time that shows the number eight in this position. This only leaves us with two
possible answers. Can you spot which one shows half
past 8?

Let’s think about the first time
for a moment. And we’ll look at the digits that
come after the two dots. These are the digits that show the
number of minutes. When a number ends in zero zero, no
minutes have gone by that hour. It’s an o’clock time. This digital time shows 8
o’clock.

Our final time shows the number 30
after the two dots. Now, this number 30 is
important. Because we know that there are 60
minutes in a whole hour and half of 60 is 30, we know that the number of minutes in
half an hour will be 30. This clock then shows us that half
an hour has gone by since 8 o’clock. The time is half past 8.

Did you notice that although the
second time was wrong, it was another half-past time, wasn’t it? 9:30 is the same as half past
9. We read the time on our analog
clock as half past 8. And because we know there are 30
minutes in half an hour, we know that the digital clock that shows half past 8 is
the one that says 8:30.

These strange clocks only have an
hour hand. Olivia tells you that one of them
shows 7:30. Which one is it?

This is an interesting question
because we really have to put into practice what we know about analog and digital
clocks to find the answer. Are you ready? Maybe you noticed that these two
clocks were strange before we even read the first sentence. The first sentence tells us,
doesn’t it? These strange clocks only have an
hour hand. Remember that an hour hand on an
analog clock like this shows us the number of hours that have gone by.

The hour hand moves quite slowly,
doesn’t it, from one number to the next. Now, you might look at these clocks
and say to yourself, “I can’t tell the time on a clock that only has one hand. I need to look at the minute hand
too.” You know, this is why this question
is so interesting. If we only have an hour hand, we
can still tell what the time is, at least some of the time.

Let’s start by looking at what
Olivia says and see how we can use this to help us. She tells us that one of these
clocks shows the time 7:30. This is a digital time, isn’t
it? We know that the two digits that
come after the two dots tell us the number of minutes that have gone by. If ever we see the digits zero
zero, it means a new hour is about to start. It must be an o’clock time.

And when we see the digits three
and zero making 30 like we have here, we know that it must be a half-past time. There are 60 minutes in a whole
hour. And so, in half an hour, there are
30 minutes. So, another way of Olivia telling
us that one of these clocks shows 7:30 is that it shows half past 7.

To help us answer the question,
let’s think about what the hour hand does as time goes by. At an o’clock time, the hour hand
points directly to a number. Can you see how the hour hand in
our sketch is pointing directly to the number three? It’s 3 o’clock. In fact, because we’re thinking
about strange clocks that only have an hour hand, let’s rub out our minute hand. We can still tell that it’s 3
o’clock because the hour hand is pointing directly to that number. This is what 4 o’clock would look
like and 5 o’clock. It’s easy to tell o’clock times
when you only got an hour hand, isn’t it? We just look at the number the hour
hand’s pointing to.

Now, remember, we’re not looking
for an o’clock time; we’re looking for a half-past time, half past 7. To help us though, let’s think
about where the hour hand would be at 7 o’clock. It would be pointing straight at
the number seven, wouldn’t it? And by 8 o’clock, it would have
turned around the clock face so that it was pointing at the number eight. But at the time half past 7, we
haven’t got to 8 o’clock yet. The hour hand is only half the way
there. It’s halfway past the number
seven.

Now, which of our clocks shows that
the hour hand has moved halfway between the numbers seven and eight? Our first clock shows that it’s
halfway past the numbers six on its way to 7 o’clock. It’s half past 6. And on our second clock, we can see
that the hour hand has moved halfway past the number seven on its way to 8
o’clock. This clock shows half past 7. Telling the time might be very
tricky when you’ve only got an hour hand. But we found out there are two
types of time that we can tell, o’clock times and half-past times. The clock that shows 7:30 or half
past 7 is the one that shows the hour hand halfway in between the seven and the
eight.

What have we learned in this
video? We’ve learned how to tell time to
the half hour on analog and digital clocks.