Topic: Consequences of the Earth's rotation - calculation of time

Target group

First class of high school or technical secondary school.

Core curriculum

General requirements

II. Skills and application of knowledge in practice.

1. Using plans, physico‑geographic and socio‑economic maps, photographs, aerial and satellite photographs, drawings, graphs, statistical data, source texts, information and communication technologies and geoinformation in order to acquire, process and present geographic information.

Specific requirements

II. Earth in the Universe: Earth as a planet, consequences of Earth's movements, celestial bodies, Solar System, construction of the Universe. Student:

2) gives the characteristics of the Earth's movements and characterizes their consequences, taking into account the Coriolis force.

General aim of education

The student will learn about the calculation of time as a result of the earth's rotational movement.

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• you will explain how solar time is determined;

• you calculate the difference in solar time between places lying on different meridians;

• you calculate the difference in time between zones in two different time zones;

• you will explain the principles of introducing universal time and its meaning.

Methods/techniques

• activating

  • discussion.

• expository

  • talk.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

• exposing

  • exposition.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers.

Lesson plan overview

Before classes

• Students get acquainted with the content of the abstract. They prepare to work on the lesson in such a way to be able to summarize the material read in their own words and solve the tasks themselves.

Introduction

• The teacher explains the aim of the lesson and together with students determines the success criteria to be achieved.

• The teacher plays the recording of the abstract. Every now and then he stops it, asking the students to tell in their own words what they have just heard.This way, students practice listening comprehension.

• The students, selected by the teacher, refer the lesson they read at home before the classes.

Realization

• Expanding and enriching English vocabulary in the issues covered in the lesson - students perform language exercises included in the abstract. The teacher makes sure that the tasks have been correctly completed and gives feedback.

• The students consolidate the acquired information, discussing it with their nearest neighbors („tell your neighbor” method).

• The teacher uses the text of the abstract for individual work or in pairs, according to the following steps: 1) a sketchy review of the text, 2) asking questions, 3) accurate reading, 4) a summary of individual parts of the text, 5) repeating the content or reading the entire text.

• Work in groups. Students using source materials such as the geography book, the e‑textbook, the historical atlas and the internet, work on a drawn thematic area. Students share tasks within the group. Representatives of each group discuss the elaborated information. After each presentation, willing students complete the mind map on the board, which is a common note from the lesson for the whole class.

• Work in pairs. Students, using atlases, search for geographic objects indicated by the teacher related to the discussed issue. Discussion within the class.

Summary

• The teacher asks: If there was going to be a test on the material we have covered today, what questions do you think would you have to answer? If the students do not manage to name all the most important questions, the teacher may complement their suggestions.

• The teacher asks the students questions:

  • What did you find important and interesting in class?

  • What was easy and what was difficult?

  • How can you use the knowledge and skills you have gained today?

  Willing/selected students summarize the lesson.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Consequences of the Earth’s rotation - calculation of time

Solar noon is simultaneously recorded for the entire area located on the same meridian. The Sun is at its highest point simultaneously on the whole meridian, but at different heights in relation to the horizon. However, it is always the highest position of the Sun in a given place during the day. Of course, wherever there is a polar night, the Sun is invisible even at midday because it is below the horizon line also at the time when the Sun reaches its highest point. If an observer (located at any point on the globe) marked in the celestial sphere the place where the Sun is at its highest and connected it, in an arc, in the shortest way possible, with the point on the horizon that determines the south (S), and extended the opposite side to the zenith and further to the point on the horizon defining the north (N), this would be the line called the celestial meridian. Projection of the celestial meridian onto the surface of the Earth corresponds to the local meridian.

It has been decided that the Sun’s highest point, on any meridian, is the middle of the day, which started 12 hours earlier in the same place, i.e., at midnight. The Sun’s highest point is the basis for determining solar time. It has been assumed that at noon it is 12:00 o’clock, and the whole day is divided into 24 hours. For Earth, we describe longitudes from 0° to 180° east and from 0° to 180° west, which combined comes to 360°. With this in mind, it is easy to calculate (by dividing 360° into 24 hours) that every 15° of longitude correspond to a time difference of one hour, and that 1° of longitude corresponds to a time difference of 4 minutes. For example, if we assume that the time on the 0° meridian is noon, i.e., 12:00 local solar time, then the time on the 15°W meridian will be one hour earlier, i.e., 11:00, and on the 15°E meridian – one hour later, i.e., 13:00 solar time.

At an international conference in Washington in 1884, representatives of most of the world’s economically developed countries agreed that the prime meridian for calculating longitude and time on Earth would be the 0° meridian, passing through the astronomical observatory in Greenwich. The solar time of this meridian was called universal time.
It was also agreed that the Earth would be divided into 24 time zones assigned to all hours of the day. Each zone has a time corresponding to the solar time of the zone’s central meridian, and extends 7°30' east and 7°30' west of the central meridian. The central meridians of the zones are the 0° meridian, the 180° meridian, and all others that are multiples of 15° on both hemispheres.
A significant part of western and central Europe, including Poland, is situated in the zone of the 15°E meridian, which extends from the 7°30'E to the 22°30'E meridians. When it is 12:00 o’clock in the zone of the 0° meridian – called the Universal Time Zone or the Western European Time Zone – in our Central European Time Zone it is 13:00. In the Eastern European Time Zone (from 22°30'E to 37°30'E, central meridian: 30°E) it is 14:00. The more time zones you go east of the 0° meridian, the more hours you need to add, and the more time zones you go west of 0°, the more hours you need to subtract.

Almost all of France, Belgium and the Netherlands are within the universal time zone, but, for practical reasons, they adopted the Central European Time as their standard time in order to avoid complications at the borders with neighboring countries. Spain lies even further west, reaching as far as the time zone of the 15°W meridian, and yet it made an official decision to move its entire territory to the zone of the Central European Time. Some countries also introduce seasonal (summer) time by means of official decisions. Throughout the European Union, and therefore also in Poland, it applies from the last Sunday of March to the last Sunday of October, i.e., for approximately seven months.

Because of granting the status of Universal Time to the 0° meridian and its time zone, the 180° meridian had to be considered as the International Date Line. In some places, this line diverges from the 180° meridian because it crosses inhabited areas. The dates on its sides differ by one day. If you cross the International Date Line when traveling from the eastern hemisphere to the western hemisphere, you must subtract one day from the current date (valid on the western side of the line thus ‘gaining’ one day), and when moving in the opposite direction – from the western hemisphere to the eastern hemisphere – you must add one day to the date (valid on the eastern side of the line, thus ‘losing’ one day).

• Time zones were introduced in order to organize the readings of time on the entire globe.

• In some countries, summer time is also adopted by means of an official decision.