Daylight saving time

Wanted to write about it for long time. I don't remember when it crossed my mind first time. When I was doing my masters in Sweden, I guess I came across the method of adjusting time at certain point of time in a year. In a way it confused the hell out of me to understand why it was adopted. Eventually, I came to know that it was introduced to lower the consumption. I guess it makes sense as in the old days lighting was the only form of electrical usage. It seems they wanted to add the daylight to afternoons and reduce the light in the mornings. If you don't know what it is, let me explain to you. It is a practice of advancing clocks so that afternoons have more time and mornings have less.

Anyway, coming to the point, almost a year back I was talking to one of my friend about it and we couldn't figure out whether it was in effect during the winters or summers. Later, looking at wikipedia we were able to figure out the answer. Then I kept on thinking about it and came up with some solution of my own to find when it would be implemented in a year.

In my home country, India, we don't use daylight saving time since our daylight pattern doesn't change much through out the year. Which means we don't advance the clocks at all at any point in a year. So I thought I could take it as a reference point. Even better reference point is GMT (Greenwich Mean Time) which doesn't change just like Indian Standard Time (IST).

We always take GMT as reference when ever we want to mention the time in different time zones. For example, for now football world cup is happening in South Africa and when ever they publish schedule they do it in reference to GMT. Which means Greenwich longitude is zero degrees. Of course, you don't have to think all of this to come to this conclusion. If you know the map, you simply know that Greenwich, London is on zero degree longitude meridian.

The second step is to find the longitude of some time zone in US. I took eastern time zone and took the longitude of center of this zone from the map. You can get it from the google maps. Generally, 75 degrees is considered for the eastern time zone. So now you know that the longitude difference from Greenwich to eastern time zone is 75 degrees.

As all of you know, one degree of longitude constitutes for 4 minutes in time. If you don't know how I came to this conclusion let me explain it to you. There are 360 degrees of longitudes that go through the earth from east to west. Of course, we need to consider only longitudes since earth always rotates towards east and this is the reason you see the sun in the east when you wake up early in the mornings. Latitudes refer to north-south directions. You all know that it takes 24 hours to complete one rotation around it self. To be precise little less than 24 hours and this is the reason we employ leap years to offset this value. So it takes 24 hours for 360 degrees. Hence it takes 24/360 hours for one degree of longitude. Which comes to a value of 4 minutes (24hours=24*60 minutes).

So now you know that the longitude difference of 75 degrees comes to 75*4=300 minutes=300/60=5 hours. Which  means if the time in Greenwich is 9PM and since Greenwich is east of US, we subtract 5 hours from this time and we get the eastern standard time which is nothing but 9-5=4PM.

But when we did the calculation the time in the eastern zone was 5PM. It was summer and I was elated to know that my theory proved to me that daylight saving time would generally be employed during the summers. Of course, like I said it makes sense since they wanted to advance the clock so that afternoon would have more time. Which means there would be no need to turn on the lights in the evenings as we are advancing the clock.

Ok let me put it this way. For example, at your place during the summer sun sets around 7 in the evening. But during daylight saving time we advance our clocks one our ahead which means time would be 8 in the evening. Right? Of course sun always sets at the same time. It's just we are the ones changing the time by advancing the clocks. So you were used to turning on the lights around 7pm and since we advanced the clocks by one hour you would be turning on the lights around 8PM there by saving one hour consumption of electricity.

In the old days electricity consumption was a big issue and hence they came up with this idea. It no longer is a issue, but still people are stuck with the tradition I guess. At the same time you can argue that how about the mornings. I mean consumption in the mornings. How many of us turn on the lights in the mornings. I mean, by the time we wake up in the mornings there is already sun and so there is no need for lights. Generally, during summers sun comes up by 5 it self. So even when you advance the clock by one hour sun comes up at 6am. Not that much difference considering most of the people don't wake up at 5am.

Finally, just to let you know the clocks are adjusted backward later in the winters. Which means we lose one hour time on that specific day where as we gain one hour on the day when the clocks are adjusted one hour forward.

Over all, I found it to be very fascinating the way it came into existence. Awesome. In the end my theory made me feel happy that I was able to prove that daylight saving time is employed in the summers.

For long time, I wanted to write about it and finally here it is. Next time I'm going to write something about maps which I found very interesting. Believe me, you will too even though it might sound very trivial to you. I'm sure what ever I wrote until now might be nothing. Just curious, did you know all this before you read this or if I asked you to prove it, would you be able to do it on your own with out looking at any web sites like wikipedia? If not, then don't you think you learned something new?