Lesson Plan - Get It!
Have you ever thought about calling someone from the other side of the United States only to realize that it is either really late at night there or really early in the morning? This is because of the different time zones into which our Earth is divided. Why are they there?
- What on Earth is a time zone?
- Why do we have time zones?
These are great questions! It is time to explore time zones.
Our Earth is a sphere that rotates around the sun, resulting in a 365-day-long year. It also spins on an axis, resulting in a 24-hour day, therefore simultaneously spinning and rotating. Take a look at this silent Earth Orbit video from Brad Freese to see how it happens:
Depending on where you live on Earth, your home is located in a particular time zone. There are currently 24 time zones throughout the world. Each time zone is one hour ahead or behind the zone next to it. For instance, if you live in Denver, Colorado, you are part of the mountain time zone. This is one hour ahead of the pacific time zone, and one hour behind the central time zone.
This means that when it is noon in the central time zone, it is 11:00 a.m. in the mountain time zone, and 10:00 a.m. in the pacific time zone.
- Why do you think there are time zones on Earth?
Write down your thoughts and share them with your teacher or parent. Think about the video of the relationship between the earth and the sun. This may help you with this task.
- When thinking about how the earth rotates on its axis, what happens to the sunlight as it turns?
Consider the fact that the sun does not move but the earth spins around, and as one part of the earth has sunlight, the opposite side of the earth is facing away from the sun, making it night time.
You will get an opportunity to create your own earth and sun in the Go! section of this lesson, but until then, check out this image of our rotating Earth:
Image, via Wikimedia Commons, licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license
Knowing all 24 of the time zone names is not necessary, but knowing the names of the time zones on your continent is important. Take a look at the Time Zone Map from the Time and Date AS and find your home zone and the zones that make up your continent or country. Familiarize yourself with the names of the time zones.
As an interesting side-note, the names of the time zones in one country are different than time zones of a country with the same latitude. For example, the eastern time zone of the United States is the same latitude as the western coast of South America and the time zone there is called PET (Peru time). This make sense because the eastern time zone of the U.S. is located on the eastern side of the country and the same time zone is located on the western side of South America. It surely wouldn't make sense to call it the eastern time zone in South America!
Throughout the world, there are 24 different time zones, and all of them are in relation to the UTC, which is the Coordinated Universal Time. This is the time zone in countries like Spain, The United Kingdom, Mali, and Ghana, and much of the north and south Atlantic Ocean. This is the time zone that is the standard by which the world regulates clocks and time. This concept was not adapted until 1972!
There are two times a year that the time on the clock is changed, and this is called daylight savings time (DST) or summer time. Countries along the equator have a 12-hour day regardless of the time of year, so they do not usually participate in DST, but MOST other areas of the earth participate in daylight savings.
The inception of the idea came from Benjamin Franklin. He believed that the sunlight in the summer months was put to better use in the evenings than in the mornings, so in the spring time, clocks are moved forward by one hour. Since there are longer periods of sunlight in the summer, this extra hour in the evenings gives farmers more time to work. It also creates less of a need for electricity use because more people are enjoying the warmer weather outside than in their homes. Proponents of DST believe it saves on energy costs.
Clocks are set back one hour in the fall, because the belief is that it returns time to its original setting. Daylight savings time begins at 2:00 a.m. on the second Sunday of March and ends at 2:00 a.m. on the first Sunday of November.
- Does your country participate in DST?
- Does your county?
Some counties in some states in the United States have decided not to participate. You will explore those in the Got It?section.
Daylight savings time is an event that happens twice a year all over the world, but many people cannot explain why it happens. Now that you know, go forth and educate others about the wonders of DST!
In the Got It? section, you will research locations that do not participate in DST and discover why not.