The Concept of Time

1. The Concept of Time By: Amy Ehlers aehlers@nmu.edu

2. Understanding The Clock • This clock face has three hands. The hour hand, the minute hand, and the second hand. Notice how the numbers go in order around the clock. • The long skinny hand on this clock represents the second hand. • The second hand moves very quickly around the clock. • Every time the second hand moves, one second has passed. • In one second, a person could blink their eyes. • There are 60 seconds on every clock, the second hand starts at the 12 and when it makes it completely around one minute has passed. • Therefore, there are 60 seconds in one minute.

3. Understanding The Clock • The longer hand of the remaining two hands is the minute hand. • Each time the minute hand moves, one minute has passed. • It takes a little longer for the minute hand to move around the clock than it does for the second hand. • To understand how long a minute is, one student could use the second hand on a clock to time another student. This other student would count how many jumping jacks they could do in a minute. • The minute hand also starts out at the 12. There are 60 minutes on a clock and when the minute hand makes it completely around the clock, one hour has passed. • Therefore there is 60 minutes in a hour.

4. Understanding The Clock • The final hand, the shortest hand, is called the hour hand. • Each time the hour hand moves from one number to the next, an hour has passed. • It takes quite a while for an hour to go by. • In one hour, you could watch two of your favorite cartoon shows. • Since there are twelve numbers, there are twelve hours on a clock.

5. Understanding The Clock The following link opens up a PDF document that provides a worksheet. The worksheet covers the material on understanding the basic clock that was covered in the previous slides. The Basic Clock Worksheet

6. Telling Time: Hours • Reading a clock, is something that can be very easy but also take some time. • First, we are going to start out reading time by the hours. • Whenever the minute hand points to the 12, the time is read o’clock. Notice the o’clock written below the twelve. • And when the hour hand points to the number you say the number and then o’clock. • So according to the top clock, the time is read twelve o’clock. • On the bottom clock, it is one o’clock.

7. Writing Time: Hours • Writing time is just about as easy as reading it. • When writing time, you first write down the hour, or the number that the hour hand is pointing to. On this clock it would be 12. • Secondly, you place a colon, or two dots on top each other which looks like this : • The colon is used to separate the hour from the minutes. • After the colon, you place the minutes. Since the minute hand is on the 12, and the 12 is the beginning, the minute hand has moved zero minutes. • Therefore the time on this clock would be written 12:00

8. Writing Time: Hours • Writing the time for this clock is just like the other one, except that the hour hand is on the one. • The time on this clock would be written 1:00. • Two zeros are used because they serve as place holders. Because there are 60 minutes in an hour, two digit numbers will be used.

9. Telling/Writing Time: Hours The following link opens up a PDF document that provides a worksheet. The worksheet covers the material on telling and writing time, that was covered in the previous slides. Hours Worksheet

10. Telling Time: Half Hours • As you can notice, the face of this clock appears to be different than the other clocks we have been looking at. • There are markings in between each number. Each marking represents one minute. • If you count each marking, starting at the one after the 12, you will notice than when you hit the 1 marking, that you have reached five minutes. • Keep counting, and when you reached the 2 mark you will notice that you have already reached 10 minutes.

11. Telling Time: Half Hours • As you make it all the way back around the clock, to the twelve mark, you will notice that each time you hit one of the numbers it was an increase of five. • Example: at the 1 it was 5 minutes, at the 2 it was 10 minutes, and at the 3 it was 15 minutes. • So when the minute hand reaches the six you know that 30 minutes have gone by, or half an hour, since it has gone half way around the clock. • Therefore the time on this clock would be 2:30.

12. Telling Time: Half Hours The following link opens up a PDF document that provides a worksheet. The worksheet covers the material that was previously covered on half hours. Half Hour Worksheet

13. Telling Time • Now that you have gotten the basic concept down of telling time, we can continue to work our way around the clock. • To figure out how many minutes have gone by in the hour, it is easy to count by fives as the minute hand passes each number. • Now what happens if the minute hand is between two numbers? • Well that’s easy, if the minute hand were on the second line between the three and four, then you would count by fives until you get to the three, which would be 15, and then you just continue counting, 15, 16,17, until you got to the line the minute hand was pointing to.

14. Telling Time • To tell the time on this clock, you would first start by figuring out the minute hand since that is the hard part. • Start by counting by fives, starting at the 1; 5, 10, 15….. All the way up to 55 which is what the 11 is. • Then since the minute hand is pointing three marks past the 11, you would count 55, 56, 57. • 57 minutes have passed in that hour. • Since the hour hand is pointing at the five, the clock reads 5:57.

15. Overview The following link opens up to a PDF, that contains a worksheet going over all that was covered in this PowerPoint presentation. Review Worksheet

16. Extra Practice • Interactive Clock • Time Telling Game • The Talking Clock