Topic: Solar Time

Supplementary material for use in lessons in the group of natural sciences (nature, biology, chemistry, geography, physics), additional classes, science clubs. It can serve as a resource for expanding knowledge, preparing students for science competitions.

Target group

Students of an elementary school (geography).

Core curriculum

Grade VI – geography
V. Earth Movements: Earth in the Solar System; rotational and reciprocating motion; consequences of Earth movements. Pupil:
3) explains the relationship between the rotational movement and the voyage of wandering and towers of the Sun, the existence of day and night, the daily rhythm of human life and nature, the occurrence of time zones.

General aim of education

Students point and calculate the solar time of a given place based on its longitude.

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• indicate the solar time of a given place based on its longitude;

• calculate the difference between the solar time of places located on different meridians.

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

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, referring to the previous lesson, asks the chosen student to determine the location of the selected point on the map and to set a different point, having his coordinates at his disposal (both points should be on the same meridian).

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

Realization

• Students will get acquainted with the content of the abstract. Then the volunteers perform interactive exercises No. 2‑6 on the interactive whiteboard. The teacher records the number of correct solutions.

• Together with the pupils, the teacher analyzes the interactive illustration showing the relationship of longitude with the solar time and explains the rules for calculating the solar time.

• The instructor asks selected students to do exercises on the interactive whiteboard that have not been done correctly before. Pupils discuss correct solutions.

Summary

• Students independently perform interactive exercise No. 1..

• Volunteers explain the dependence of the solar time of a given place on its longitude.

Homework

• Develop a lap book containing issues learned during the lesson and bring your work to the next class.

• Listen to the abstract recording at home. Pay attention to pronunciation, accent and intonation. Learn to pronounce the words learned during the lesson.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Solar Time

The moment of the Sun’s zenith occurs simultaneously in all points lying on the same meridian. The Sun reaches its zenith at different heights, but everywhere it reaches the highest altitude during that part of the day. The time that passes between successive Sun shines, is called a day. The Earth is doing one revolution around the axis in this time. It was assumed that at the moment it reaches its zenith, it is exactly 12:00 pm solar time. The whole day lasts 12 hours before this and 12 hours after this moment. The whole day is therefore divided into 24 hours. Knowing the rotation time of the Earth and knowing that every point on it turns a circle, you can calculate at what rate the Earth rotates.

360° : 24 hours = 15°
One hour is 60 minutes. Let us now calculate how many times the Earth will turn by 1°.
60 minutes : 15° = 4 minutes

And what is the difference between time on different meridians? Let's take the difference between the two meridians, 12⁰E and 26⁰E, for example. We know that on the 12⁰E meridian it is 12:20. First, calculate the difference in longitude. It should be taken into account that both places lie on one hemisphere. In this case, subtract the values.
26⁰E - 12⁰E = 14⁰
So we know that the meridians are 14 degrees apart. We also know that the Earth rotates at the rate of 1 degree in 4 minutes. So we can calculate the difference in solar time.
14⁰ x 4 minutes = 56 minutes
The meridian 26⁰E lies east of 12⁰E. Therefore, add the result to the known time.
12.20 + 56 minutes = 13:16
On the meridian 26⁰ it is 13:16.

And what if the meridians are in different hemispheres? Let's assume that on our meridian 12⁰E it is still 12:20. We want to find out what time it is on the 24⁰W meridian. If the meridians are in different hemispheres, to calculate the local time, add their values.
12⁰E + 24⁰W = 36⁰
Now we calculate the difference in time:
36⁰ x 4 minutes = 154 minutes (2 hours and 34 minutes).
We now calculate local time. The 24⁰W meridian lies west of 12⁰E – in which case we have to deduct time
12.20 – 2 h 34 min = 9:46

On the meridian 12⁰E it is still 12:20. Let's now calculate where the meridian is midday at the moment. If in 4 minutes the Earth rotates by 1⁰ and the time difference is 20 minutes, then we can calculate the meridian we are looking for.
20 minutes : 4⁰ = 5⁰
The meridian is located 5 ° further. But in which direction? Since we have an hour later, we have to head west.
12⁰E - 5⁰ = 7⁰E
Midday is now on the meridian 7⁰E.

• When the Sun reaches its zenith it means noon in solar time.

• The day lasts 24 hours.

• 1⁰ Longitude corresponds to 4 minutes of solar time.