Daylight Saving Time (DST)

On first Sunday of November ( 4th November 2012)

All the clocks in US had gone back one hour .( on 4th November at 2 am)

Which means 2 am had become 1 am.

Again on the first Sunday of March every year, clocks will go forward one hour. 

2 am will go forward to 3 am. It is done every year.

In winter, the clock goes backward one hour.

In summer ( spring ), the clock goes forward  one hour .

This time adjustment is called Daylight Saving  Time .( DST)

It is not only done in US.  done in countries like,

UK, Canada, Australia, etc.,

But done on different dates.

In India, we do not have this Daylight Saving Time  ( DST). 

We have same timings throughout India , throughout the year, without any seasonal adjustment. 

Hence it is called Indian Standard Time IST ( IST is  followed in Srilanka)

If in Bangalore it is  6 am, in Hydrabad also 6 am, in Calcutta also 6 am, etc

Small countries like Srilanka, Pakistan, Bangladesh , Indonesia,  etc do not have DST

In India,  for a short period DST was introduced during Sino-Indian War ( 1962 ) and Indo-Pakistani Wars in 1956 and 1971

In California,  if  it is 6 am,  in India it is  7:30 pm  pm ( 13 :30 hrs difference, 

from Nov. to March )

In California,  if it is  6 am , in  India  it is  6 : 30 pm ( 12:30 hrs difference , 

from March to Nov)

If I want to speak with someone in India at 7 :30 pm ( IST), I must talk from California at 6 am. ( Nov to Mar)

If I want to speak  with  someone in India at 7:30 pm, (IST), I must talk from California at 7 am . ( March to Nov)

On first Sunday of every March, the clock time will move forward one hour.

On first Sunday of Every November, the clock will move backward one hour. 

At what time, the change takes place ?.

It  is  at 2 am early morning, NOT AT 12  MIDNIGHT

Early morning at 2 am, the time changes automatically in Laptops and Cellphones.

It is a wonder to see that the  time  automatically changes in cell pones and Laptops, These are programmed for the change.

In Watches,  it should be manually done. 

Why  it is done at  2 am  ? why not  at 12 midnight?

If the time is changed manually at 12  midnight in watches, the day change at 12 mid night will be affected.

In the watches ' day change '  takes place at 12 midnight.  Eg. Monday changes to Tuesday.

If the watch needles are handled at 12 midnight, the  day change will be affected,

For this purpose ,  the time  change is made at 2 am .

How the Time change is helpful  to  the people?

Winter is very chill, in some states snow  on roads  are formed. 

Because  the time goes back one hour , those who are going to the office 

at 8 am , can go after one hour.That one hour margin is very help to manage the chill mornings in the winter.

Even though the Clock time goes back one hour, the duration  of one day which is 24 hours,  remains the same.

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For students.

Time ( capital T ) and time ( lower  t ) are different.

time ( lower t) is clock or watch time that changes from country to country.

Time ( capital T) is the interval between two events, it is the  same everywhere.

In a clock, the two needle staying together at 12 ,  to come back to 12 again , will take 12 hrs.

This  is the duration, which  is  called Time.

It will be  same in US , India and everywhere. 

But clock time changes from country to country.

Time- காலம் 

time -  நேரம்

A train leaves Bangalore city at 6 a.m and reaches Chennai at 11 am.

Here, the  Time taken is 5 hrs  is காலம் ( there is no a.m or p.m for Time)

Departure time is 6 a.m நேரம்

Arrival time 11 is  a.m நேரம்

a.m means ante meridiem = before noon

p.m means post meridiem= after noon.

For a.m and p.m  only lower letters should be used not A.M and P.M

 

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From the period of Aristotle  to the  period of Albert Einstein, the Time was considered as absolute.

Which means Time ( நேரம்) is the same in  any frame.( moving frame or stationary frame )

Great Einstein proved in 1905 that  the Time is Relative , 

Time changes from moving frame to stationary  frame.

If person is travelling at the speed of 2,40,000 Km/sec.

For him,  if  the Time passed is 6 hrs, for a person remaining in the station, the Time passed is 10 hrs.

Yes, for a person remaining in the moving object , the Time passed is 6 hrs ( less)

But for the person remaining in the stationary place , the time passed is 10 hrs.(more)

Unbelievable ?  It is a  well established truth. The speed should be 2,40,000 Km/sec.

Einstein had proved it theoretically and became a great celebrity of the millennium.

Then, it was practically proved in case of Muons  extended life.( Muons = Sub-atomic particles ).

It took many years for me to understand  this truth  with  proper calculations.

The day , I understood it, my mind went to ecstasy and I was in a state of euphoria for many days.

What a  great discovery, what a great Scientist was Albert Einstein.

In the year 2011, I called so many physics graduates and engineering students and explained it with calculations. 

They could not believe that the  Time also changes and it is relative.

Newton believed that the Time is absolute, Einstein prove that  the Time is relative.

Einstein's eminence in excellence can be understood , when his calculation is understood. It is a great luxury.

On one occasion, some one asked me, " which is your great achievement  ?" 

 I said,

" Having understood Einstein ", Yes, whoever had understood ' The theory of Relativity ' would say the same answer.

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