Yeah,
the world over. One measurement that remains universal is the
measurement of time. For centuries, towns and cities kept their own
time. Then, in 18 84 it's something called the International
Meridian Conference. It was decided that all time would be
based against Greenwich Mean time. Time's up. Dead dead
B maybe in a taste of these are out of your charms. Maybe it up. You
remember what time it really is yet? Two timer? No,
not that kind of mean. I mean, in this instance is a
standard time all over the world, based on what the time is at any given
moment of day or night in a precise location. Greenwich,
England. The line of longitude, which runs through Greenwich,
is called the Prime Meridian. As we travel east from
this line, the time of day becomes later. And when we travel
west to the prime meridian, the time of day becomes
earlier. Let me show you on the globe. The
world is divided into 24 these time zones that
were created to coincide with the 24 hours in a day, the time it
takes the earth to complete one revolution on its axis.
and each time zone represents one hour.
So when it's 11 a.m. here in Greenwich, England,
it's only 6 a.m. clear over here in Orlando,
Florida, because it's
12345
time zones away. Once again, here is
Greenidge, England, and the time it takes the earth to rotate from here
to here is one hour. In other words, if it's
4 a.m. here in Greenwich, England, then it's only
3 a.m. Here. One hour is
subtracted because we're traveling west of the prime Meridian. And during
every 24 hour period, the earth revolves 360
degrees. So time is actually the major of
change. And change in this instance means the Earth's
movement on its axis through each degree of its 360
degree revolution. I hope that wasn't too
confusing.
Hello? Oh, hello, Meter. Uh huh.
You say you think you understand, But you're not sure. Add, don't worry,
meter. Whatever you didn't get will cover a little later.
And that goes for you, too. Now let's look at the units that we
use to measure time after time
is measured in seconds,
minutes, hours,
days, weeks,
months, years
decades, centuries
and millennia.
Let's begin with the smallest unit of time measurement and work our
way up. A second is a very short period
of time altogether, say 1001
ready 1001 and the length of time it took
us to, say, 1001 approximately one second
past and doing mathematical calculations using time.
The abbreviation for second is s.
To see how closely we estimate an actual minute on your own,
try looking at a clock and counting. From 1001 to
1060 you can use an analog clock like
this or a digital clock like this. And a
minute should have passed. When you say 1060 for instance,
123
4058 1059
1060 So they're 60 seconds in a
minute, and we can approximate How long that takes.
Abbreviation for minute is M i n. And we used minutes a great
deal. Usually your classes or 50 to 55 minutes in
length, like the one we see here ending at 3 p.m.
We recorded in minutes the amount of time it takes a runner to run a
mile. The next unit of time is the hour,
and there are 60 minutes in an hour, and most people work eight
hours out of each day. According to this clock. It is
now 12 o'clock noon, when the large hand moves all the
way around the clock returning to 12 and a small hand is moved to
the one an hour has passed. Each of the
small markings on the clock represent minutes. Therefore,
there are 60 of these marks around the face of the clock,
each representing to 60 minutes in one hour.
Sometimes it's necessary to change hours, two minutes and seconds.
For instance, feature length movies are usually timed it somewhere
between 90 and 120 minutes. So to change from larger
units of time, like the hour two minutes or seconds, we need to multiply.
Let's say we wanted to know how many minutes were in two hours,
30 minutes. The first thing we would do is multiply the number of
hours two times the number of minutes in an hour, which is 60
and the product is 120 meaning there are
120 minutes in two hours. Now all we
need to do is add the remaining 30 minutes to
this, so that means the sum is 150
there 150 minutes
in two hours, 30 minutes. Now let's find out
how many seconds that is to do that. We simply multiply
again by 60 because there are 60 seconds in
one minute, so 150
times 60
equals. Wow,
9000. There are 9000
seconds in two hours, 30 minutes. That's a lot
of seconds, isn't it? The next unit of measure is the
day, and the day is equivalent to 24 hours.
Again, let's look at our clock. Let's begin with
12 o'clock when the small hand on the clock the hour hand has made
1 360 degree rotation and it's back to 12
o'clock. This is half a day when the hour hand has made
one Maur 360 degree rotation for a total of two
rotations. One day or 24 hours has
passed. We divide days into a M and
P M for one second after midnight until one second
before noon. We call this a M or morning hours
but from one second after 12 noon until 12 o'clock
midnight we call P. M. That means that the 1st
12 hour rotation of the clock is morning or a M,
and the 2nd 12 hour rotation is PM or afternoon and evening.
That means that the 1st 12 hour rotation of the clock is morning or
a M, and the 2nd 12 hour rotation is PM or
afternoon and evening. Have you ever wondered where the expression
midnight midday comes from? On March 21st in
September, 22nd of each year and equal Knox occurs
equinoxes, a word we used to signify equal amounts of
daylight and nighttime. So during the equinox, there
exactly 12 hours of daylight and 12 hours of
darkness, they're equal. On each of these two days, daylight
begins at 6 a.m. An evening begins at 6 p.m.
Six hours to added to 6 p.m. Brings us to 12 o'clock,
midnight, halfway or midway through the night,
and that's why we call it midnight. And when we had six hours to 6 a.m.
or daybreak, the time becomes 12 o'clock and we're
halfway or midway through the day, so we call this
midday or commonly referred to his noon.
So let's review what we've had. So far we have had
four units of time. We've had
seconds, minutes, hours and
days. We learned that there's 60 seconds in a minute,
60 minutes in an hour, 24 hours in a
day. And that brings us to our next unit. There are seven
days in a week, and there are
4.5 weeks or 30 days in a
month.
Hello. Oh, hello, meter. It's my brother meter again.
You what? Yes, there are, he says. He flipped through
his calendar and he found out that not all months have 30 days. Some
have Maura and one has less. What's that mean?
Ah, so he's asking why? I told you. There are 30 days
in a month. We'll meet her. I'll explain that to him right now. Thanks for calling.
Bye meters, right? Not all
months do have 30 days. But if you take the total number of days in a
year, which is 365 and divide it by 12 the number of
months of the year, the average comes out to be just a little more than
30. So that's why we say there are 30 days in a month.
Now let's look at the next unit of time. The year,
Like we said, there are 12 months in a year or
365 days. 10 of these years equals a
decade, and every 100 years is
called a century, and every 1000 years is
called a millennium. The year
2001 marked the beginning of a new millennium as well as a new
century. People all over the world did special things to
celebrate it. In London, they've built this the London
eye, which gives visitors a bird's eye view of this ancient
city. Aren't you excited to be living in a new millennium?
You know, people only get to do this every 1000 years.
Incidentally, all of these periods of time we've talked about
have abbreviations. With the exception of Day and millennium.
Second is abbreviated as s
minute is my end. Our
age days, we said, has no abbreviation.
Week is wk
Months is M O, and year
is why are and
CNN is the abbreviation from century.
Now it's time for some real world applications. Let's see how
well you can apply what you've learned. How about this one?
The Atlanta Braves baseball team left Atlanta, Georgia, for a game in San
Francisco, California at 2 p.m. The flight lasted
three hours on the plane landed at 2 p.m.
Is it possible to leave and arrive at the same time
that your first reaction is? No. But let's think about this. Look at
my map. Here's Atlanta and
here. San Francisco, California See these time
zones? Notice that in order to travel this distance, the
team is passing through one,
23 time zones. Remember each time
zone west of where you begin is an hour earlier than
where you are. This means that when the team left Atlanta,
the time was only 11 a.m. In San Francisco.
So when the team has traveled three hours, it will be three hours
later in San Francisco. When three hours is added
to 11 a.m. It becomes two PM Let's look at another
example. Ah, local doctor told his patient that its heartbeat
72 times each minute. If this is true, how many times
would your heartbeat in a day? Which do you think would be a
better estimate as to the number of times your heart beats in a day. Would
it be a 1000 be 10,000
C 100,000 or D one
million? Interesting question. Let's work it out together.
Using a calculator, we'll start by putting 72 into the
calculator that represents a number of
times it beats him one minute. Now multiply by
60 to find the number of times that
beats in an hour. It beats
4320 times in an hour.
Now, since you're 24 hours in a day, we now multiply
by 24 and the product
is
103,680.
So our answer is, that's right, see
100,000. So as you can see calculating
problems dealing with time is something you can use every day. Whether you're
figuring out the number of times you can jump rope in a minute or the length of
the seasons of the year. Whether you'll be able to stay up long enough to watch your
favorite TV show on a school night or how long you can get
your paper plane to fly, I hope you've enjoyed our look a
time and until next time this is Miles MK leader,