Time is very precious as far as every person in this world is concerned. As the old proverb goes,” Time and tide wait for no man”. It means that time is valuable and lost time cannot be found again. So, we always use different units to express time in our daily life. We have different units for a time like seconds, hours, days, weeks, months, and years. Here, we will discuss how a year is defined and how many days are there in one year. For a larger quantity of time, we use units like months,years, and so on and for smaller quantities of time we use units like seconds, minutes, and so on.
What is a Day?
The day is the time interval taken by the earth to complete one rotation about its own axis. The earth is continuously rotating about its axis. The formation of day and night is due to the rotation of the earth about its own axis. In fact, Earth rotates on its axis from west to east. The earth will take 24 hours to complete one rotation about its own axis. We can calculate the duration of a day by measuring the time interval taken by the sun to reach the highest point of the sky twice.
1 day = 24 hrs
We know that one hour is equal to 60 minutes and one minute is equal to 60 seconds.
1 day = 24 x 60 min = 1,440 min
1 day = 1440 x 60 sec = 86,400 sec
The side of the earth which is facing the sun will receive the sunlight and experience the daytime. The opposite side of the earth facing the sunlight will not receive any sunlight. Hence, this opposite side of the earth will experience night. But as the earth rotates about its own axis, the side of the earth receiving the sunlight changes and the opposite side of the earth will receive the sunlight now. Therefore, if one side of the earth is experiencing daytime, then the opposite side will experience nighttime. Countries like India and the USA lie on the opposite side of the globe. So, if it is daytime in India, then it will be nighttime in the USA.
How Many Days in 1 Year?
Let us see how many days are 1 year. In a Gregorian calendar, there are two types of years. They are common years and leap years. There are 365 days in a year. A leap year consists of 366 days. The leap year comes after every four years.
1 year = 365 days
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A year is considered as the time taken by the earth to revolve around the sun on its elliptical orbit. The earth takes 365 ¼ days to complete one revolution around the sun around the elliptical orbit. But the number of days in one year is 365 days. After every four years, the extra quarter day (¼ day) is added up to form one day and this day is added to the number of days in a leap year. This is how the leap year gets an extra day compared to the common year.
How Many Days in Each Month?
Each year is divided into 12 months and each month consists of days varying from 28 to 31. The different months in a year and the number of days in each year is given in the table below.
Name of the Month | Number of Days in a Month |
January | 31 |
February | 28 (29 in a leap year) |
March | 31 |
April | 30 |
May | 31 |
June | 30 |
July | 31 |
August | 31 |
September | 30 |
October | 31 |
November | 30 |
December | 31 |
As we have discussed, the leap year contains 366 days and the extra one day is given in the month of February in a leap year. In a common year, the month of February contains only 28 days. But in the case of a leap year, the month of February contains 29 days.
How to Identify a Leap Year?
We have already discussed how an extra is given to a leap year. Each extra quarter day that is not included in the common year is added to form a complete one day after four years. This extra day added to leap year is called leap day. Therefore, the leap year repeats after every four years. To identify whether a given year is a leap year or not, we have to divide the year by 4. if it is divisible without leaving any remainder, then the given year is a leap year. If it is not divisible and leaves some remainder, then the given year is not a leap year.
Eg: The year 2024 is divisible by 4 leaving no remainder, therefore, it is a leap year.
The year 2019 is not divisible by 4. Therefore, the year 2019 is not a leap year.
The year 2016 is divisible by 4 and so it is considered as a leap year.
However, this method of checking the divisibility of a year by 4 is not the criteria to identify the leap year for years which are multiples of 100 like 1600, 2000, 1800, 700, and so on. For these types of years, we will check if the given year is divisible by 400. If the given year is divisible by 400, then the given year is a leap year.
Eg: The year 2000 is divisible by 400 leaving no remainder, therefore, it is a leap year.
The year 2100 is not divisible by 400. Therefore, the year 2100 is not a leap year.
Conclusion
The time taken by the earth to complete one revolution is called a year. The earth takes 365.25 days to complete one revolution around the sun. In a Gregorian calendar, a common year contains 365 days which is divided into 12 months. A leap year contains 366 days and it repeats after every four years. In a leap year, the month of February has 29 days. If a given year is divisible by 4, then it is a leap year. For years that are multiples of 100, we check the given year is divisible by 400. If it is divisible by 400, then it is a leap year.
