Telling Time By: Sophia James Education, LLC

Transcription

1 Telling Time By: Sophia James Education, LLC The world is fascinated by how time goes by fast or how we never have enough time in a day. For ages the concept of time have fascinated people. For thousand of years time was measured by observing the movement of the sun, moon, or stars. We have used sundials and also clocks for many years to measure time. In order to record or indicate time devices were created. The devices are clocks, watches, and sundials. The oldest of these three devices are the sundials or shadow clocks. Many years ago people used sundials to indicate time of the day by the position of the shadows of objects on which the rays of the sun falls on. Throughout the day the sun moves across the sky, causing the shadows of the objects to move. Clocks, are machines that performs regular movements in equal intervals of time and is linked to a counting mechanisms that records the number of movements. The word clock comes from the Greek hora ( time ) and logos ( telling ). All clocks, of whatever form, are made with the principle of regular movements and equal intervals. Sometimes it is important to measure time exactly, such as when conducting an experiment or baking or when setting an appointment. Sometimes accuracy is not so important example when we are on vacation and have no timed plans. It is believed that shadow clocks or sundials known as gnomon, were the first device for indicating time. This sundial consisted of one vertical stick or pillar; the shadow that it cast gave an indication of the time of the day. As time passed these sundials became more complex and telling time through different type of clocks were invented. If you would like to build a pretty accurate sundial you can click here and print one. Around 1582 Galileo noticed the timekeeping property of the pendulum at this time the pendulum which was a weight attached to a predetermined size cord it was used by medical doctors to count the pulse of patients. Around 1656 the Dutch astronomer and physicist Christian Huygens started using the pendulum as time controller in clocks. His invention brought great importance and extent to clockmaking. Clocks, weight driven, with short pendulums, were encased in wood and made to hang on the wall. An English clockmaker, named William Clement, introduced the long, or seconds, pendulum in After that they enclosed the pendulum and weights, that is when the long case or grandfather clock was born. Our modern mechanical clock consists of gears that transmits motion from a weight or spring to the minute and hour hand. They are very accurate and they move steadily. A simple 12 to 1 gearing, known as motion work, gives the necessary step down ratio to drive the hour hand. The spindle carrying the minute hand is provided with a simple slipping clutch that allows hands to be set to the correct time. Watches were mostly made in England by hand, most of the watches were pocket watches for men. It is said that one day an English, horse dealer, was traveling through Swiss one day and his watch was broken. He showed the watch to a blacksmith who had a son named Daniel Jean Richard ( ). Daniel was fascinated with the watch and implored the Englishman to repair it. Daniel was so intrigued with the watch that he decided to make a watch himself, after 18 months he succeeded. The five sons of Jean-Richard ended by devoting themselves to this new industry. The opportunity to work indoors during the long winter months was welcomed by the Swiss community. By the 1800 whole families were making parts of watches and the master maker would then assemble and market these watches. In 1850 Swiss invested in the machinery necessary to watchmaking. By 1900 the Swiss production surpassed the British production. By 1914 wrist and bracelet watches were firmly established. By the 1920 s watch making was Switzerland s most important industry. Today many things that we do are connected to time. There is a time for everything under the sun. For students being able to understand time is important.

2 In the United States under the Common Core Standards, learning about time starts in the first grade. In first grade students learn to Tell and write time in hours and half-hours using analog and digital clocks (CCSS.Math 1.MD.B.3). By second grade students are expected to tell and write time from analog and digital clocks to the nearest five minutes, using a.m. and p.m. (CCSS. Math 2.MD.C.7). In third grade students are expected to Tell and write time to the nearest minute and measure time intervals in minutes. Solve word problems involving addition and subtraction of time intervals in minutes,e.g., by representing the problem on a number line diagram (CCSS. Math.3.MD.A.1). Finally by grade four, students are supposed to CCSS.MATH.CONTENT.4.MD.A.1 Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table. For example, know that 1 ft is 12 times as long as 1 in. Express the length of a 4 ft snake as 48 in. Generate a conversion table for feet and inches listing the number pairs (1, 12), (2, 24), (3, 36),... CCSS.MATH.CONTENT.4.MD.A.2 Use the four operations to solve word problems involving distances, intervals of time, liquid volumes, masses of objects, and money, including problems involving simple fractions or decimals, and problems that require expressing measurements given in a larger unit in terms of a smaller unit. Represent measurement quantities using diagrams such as number line diagrams that feature a measurement scale. MEASURING TIME: Problems using measurement of time will happen throughout grade school, therefore a strong foundation of the skill is important. In order for students to understand time it is important for students to have mastered numbers recognition up to 60. To measure time we use seconds, 1 second as measured by International Atomic Time. There are 60 seconds in each minute. There are 86,400 seconds in one day. There are 60 minutes in each hour. There are 24 hours in one day. There are 7 days in 1 week. There are between 28 and 31 days in 1 month. There are 365 days in 1 year. There are 10 years in a decade. There are 100 years in a century. Finally 1000 years in a millennium. Reading Time: Reading time is a complex skill that will be used throughout life. It is important to look carefully where the hands of the clock or watch points to. The hour hand is shorter and moves around slowly. The minute hand is longer than the hour hand. The minutes hand moves past the hour or to the next hour. Most clock faces show the minutes in groups of five, and in between minutes as a short line or mark. Clocks usually have a very thin, long hand that usually moves quickly around the face of the clock every minute, marking 60 seconds.

3 Name: Date: Worksheet # 1 Purpose: To be able to tell and write time in hours and half-hours using analog and digital clocks Standard: CCSS 1.MD.B.3 Draw the hour hand and minute hand in order to tell the correct time: 12:00 4:30 2:00 7:00 8:30 7:30 6:00 8:00 1:30 12:00 9:30 1:00 2:30 3:00 12:30 3:30

4 Name: Date: Worksheet # 2 Purpose: To be able to tell and write time in hours and half-hours using analog and digital clocks Standard: CCSS 1.MD.B.3 Draw the hour hand and minute hand in order to tell the correct time: 4:00 4:30 2:00 7:00 9:30 10:00 6:00 8:00 1:30 12:00 9:30 1:00 :30 3:00 12:30 3:30

5 Name: Date: Worksheet # 3 Purpose: To be able to tell and write time from analog and digital clocks to the nearest five minutes, using a.m. and p.m.. Standard: CCSS 2.MD.C.7 Draw the hour hand and minute hand in order to tell the correct time: 12:25 5:55 3:00 7:05 8:10 7:15 6:45 8:20 1:40 12:55 9:35 1:10 2:50 3:30 12:35 3:45

6 Name: Date: Worksheet # 4 Purpose: To be able to tell and write time in hours and half-hours using analog and digital clocks Standard: CCSS 1.MD.B.3 Draw the hour hand and minute hand in order to tell the correct time: 3:40 2:35 2:50 7:15 8:55 7:15 6:05 8:45 1:10 12:35 9:05 1:20 2:40 3:50 12:35 3:15

7 Name: Date: Worksheet # 5 Purpose: To be able to tell and write time from analog and digital clocks to the nearest five minutes, using a.m. and p.m.. Standard: CCSS 2.MD.C.7 Draw the hour hand and minute hand in order to tell the correct time: Then use the information from the clock to answer the questions. 12:25 5:55 3:00 7:05 One hour later: One hour later: One hour later: One hour later: 1:40 12:55 9:35 1:10 One hour later: One hour later: One hour later: One hour later:

8 Name: Date: Worksheet # 6 Purpose: To be able to tell and write time from analog and digital clocks to the nearest five minutes, using a.m. and p.m.. Standard: CCSS 2.MD.C.7 Draw the hour hand and minute hand in order to tell the correct time: Then use the information from the clock to answer the questions. 12:25 5:55 3:00 7:05 One hour later: One hour later: One hour later: One hour later: 1:40 12:55 9:35 1:10 One hour later: One hour later: One hour later: One hour later: