[Physics Class Notes] on Standard Time Pdf for Exam

Do you know there are 24 time zones in the world? A time zone is an area where a uniform standard time is followed for all the purposes such as legal, commercial, social etc and where the entire region regulates their clocks and time according to a standard time. These are generally defined as offsets from the UTC i.e. Coordinated Universal Time. In this article, we will be talking about the standard time. We will learn what is standard time and other aspects related to this such as EST time, time UTC, PST, PDT, CST, MST, etc that will help you to understand the concept of standard time.

Introduction

Time is considered as a continuous event that occurs in succession and follows a path of past, present and future where the events that have occurred in the past will never come back and talks about ongoing events in the present and succeed towards the future events. It is an ongoing process. Due to the rotation and shape of the Earth, all places of the world don’t receive sunlight at the same time which leads to making a difference in morning, evening and night in all the places because of which we need different time zones. That is why Earth is divided into 24 time zones according to which all the localities of that zone follow a uniform standard time.

Meaning of Standard Time

In a particular geographical region, the synchronisation of the clocks with respect to a single time is called a standard time rather than following the local mean time standard. Generally, the standard time is based on some longitude which usually passes through the centre of the region or the country and all the clocks of the region regulate their timings with respect to this longitude or meridian. 

History

In 1869, the usage of time zones was proposed by Charles F. Dowd according to which localities of the zone will use the same time and then Sir Standard Fleming and others also advocated this idea. In 1883, time zones were adopted by the US and Canada railroads. In 1884, Greenwich Royal Observatory at 0° was adopted as the meridian of transit in the International Conference held at Washington DC. The adoption of 24 time zones was done with those whose boundaries were defined by the local authorities. DST i.e Daylight saving time was adopted during World War I in various countries to save fuel in order to reduce the requirement of artificial light in the evening hours, the clocks were kept ahead or advanced by one hour.

Time UTC

UTC is an abbreviation used for Coordinated Universal Time. It is considered as the primary standard time according to which the countries of the world regulate their time and clocks. In simple words, it works as the basis for civil time today. The other names of this are Universal Time Coordinated and Universal Coordinated Time. It is a successor of GMT i.e. Greenwich Mean Time. It is fixed and no usage of daylight saving time is done here. It is located at 0° longitude i.e Prime Meridian and sea these are 7.5° West and East longitudes. This standard time is kept by the usage of atomic clocks which are combined with the rotation of the Earth. 

What about GMT?

It is an abbreviation for Greenwich Mean Time. It is also used as a basis for the countries of the world to regulate their clocks and timings. It is a clock time at Royal Observatory, Greenwich, London and this time means solar time that is counted from midnight. Sometimes it is used as a synonym of UTC but nowadays it is just a time zone, not a time reference. And it is equal to UT1 which means solar time at 0° but it can differ with respect to UTC by up to 0.9s. It is often used by the countries associated with the United Kingdom. 

EST Time

EST Time is an abbreviation used for Eastern Standard Time or Eastern Time. It is a standard time which is 5 hours behind the UTC i.e. Coordinated Universal Time in Autumn/Winter whereas it is 4 hours behind the UTC when observing the daylight saving time in Summer/Spring. EST time zone time is observed in some parts or all of the 23 states of the Eastern US, eastern parts of Canada, Quintana Roo state in Mexico, Panama, Columbia, Ecuador, Peru, some parts of western Brazil, Caribbean and Atlantic islands. 

PST Timing

It is an abbreviation for Pacific Standard Time or Pacific Time. It is behind UTC by eight hours whereas it is behind by 7 hours when observing daylight saving time. It is observed in some parts of western regions of Canada, the  US, and Mexico. DST which is Daylight Saving time is used in this zone. In this zone, when standard time is used it is called PST i.e Pacific Standard Time whereas when daylight saving time is used it is called PDT i.e. Pacific Daylight Time. Los Angeles is the largest city in this time zone.

CST

It is an abbreviation used for Central Standard Time or Central Time which is found in North America. It is observed in some parts of the US, Canada, Mexico, Central America, the Eastern Pacific Ocean and the Caribbean islands. Current time CST can also be used with respect to the UTC. When standard time is used it is 6 hours behind the UTC whereas when daylight saving time is used it is 5 hours behind the UTC. Mexico City is considered the largest city in this time zone. It is denoted by CST and CDT depending upon whether daylight saving time is used or not. 

Sometimes, CST abbreviation is also used for China Standard Time and Cuba Standard Time which must not be confused with Central Standard Time. If we talk about China standard Time, it is ahead by 8 hours whereas Cuba Standard time is behind by 4 hours from the UTC. 

Time in MST

MST is an abbreviation used for Mountain Time Standard in North America. This time is based on the mean solar time at the 105th meridian which is observed west of Greenwich. It is also called Mountain Time ( MT ). It is observed in the US, Canada and Mexico. When standard time is used it is 7 hours behind the UTC whereas when daylight saving time is used, it is considered as 6 hours behind the UTC. This time zone is observed as in the east of Pacific Time and west of the Central Time zone in the US and Canada.

Sometimes, MST abbreviation can be used with respect to the standard time of any country or region such as Malaysian Standard Time which is also abbreviated as MYT. This is ahead by 8 hours from the UTC.

Fun Fact

The international date line works as a boundary between two consecutive calendar dates and works as a  line of demarcation between them. It was established in 1884 and it is a  line that passes through 180° longitude from North to South. The interesting thing about it is that when you cross this line to the west, the date will forward by one means you will gain a day whereas when you travel to the east, you will lose a day. 

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Conclusion

Thus, to conclude we can say that the world is complex and the time of all different regions are much complex. In order to synchronise the clocks of a particular region or a country, standard time is used whereas the clocks and timings of the world are regulated by the time UTC. With respect to UTC, different time zones can be found in the world and standard time is followed by the regions or countries as per their requirements and it is generally based on the longitude that passes through the centre of the country according to which clocks of the entire region or country regulate their timings. In this article, we have talked about standard time and its history and other related aspects which are important to understand this concept which has a vital role in da
ily lives and whenever we study about time in Physics, Geography, Earth Sciences or Geology, etc.