Concept of Time

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Welcome to class! 

In today’s class, we will be talking about the concept of time. Enjoy the class!

Concept of Time

Measurement of time

Time is defined as the period in which a process, action or an event takes place. Time is also called the Point or Period when something occurs. Time is an integral part of Physics and every single quantity in the physical world relies on it. Time has made the universe function in a simple and routine way. If time wouldn’t have existed, there would be many irregularities in the schedule and timing of people. It is quite difficult to think of life when there is no time. There won’t be any physical quantities like acceleration, velocity and electromagnetic waves which depend on time for their existence.

The most natural time unit is the solar day which is manifested by the passing of day and night. It takes the earth one solar day to complete one revolution about its axis.

1 day = 24 hours

1 hour = 60 minutes

1 minute = 60 seconds

In the International System of Units (SI), the unit of time is the second (the symbol is s).

Type of clock/watch

(1) Ticker-tape timer:

This is used to measure short intervals of time accurately. It has a steel strip with a stylus which is controlled by an A.C. it vibrates 50 times in 1 second and makes use of a paper tape which helps in calculating the distance between the dots. The distance between the dots shows the distance travelled by the body pulling the tape in cm. It is commonly used in motion and to practise the third law of motion. i.e., action and reaction are equal and opposite.

(2) Stopwatch/clock:

This is an instrument which is used to determine the time used either in the laboratory or on the field during sporting activities. It calculates both minutes and second. The second’s hand makes one revolution in one minute.

(3) Simple pendulum:

A pendulum is an instrument which is mostly used in the laboratory to measure time. The pendulum swings right to left. The time taken or the time of oscillation is determined through this instrument.

Pendulum clock has second hand made in the form of a pendulum. It oscillates in order to tick the minute’s hand and 60 oscillations of the second-hand make 1 minute.

(4) Heart-beat:

Heartbeat is a natural way of counting. It is mostly used in medical line. The heartbeat gives the pressure and the rate of pumping of blood in the body. An increase in heart-beat is an increase in blood pressure and vice versa.

(5) Sand-clock:

Sand-clock is an instrument used in measuring time per hour. The instrument could still be designed to measure smaller intervals. The sand in the glass is made to run from the top bulb to the lower bulb through a small neck. It takes exactly one hour to complete one run. It is also called hourglass.

Repetitive event

A repetitive event is an event which keeps recurring every time. Example of a repetitive event is time. There are 24hours in a day. This means that, after 24 hours which is a day, there is a reoccurrence of the event (time) in order to determine another day. The continuous counting of time makes a day, a month and a year.

 

In our next class, we will be talking about Motion in Nature.  We hope you enjoyed the class.

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