# Concept Map

## Useful websites

Pages from Wikipedia relating to this chapter

1. thought provoking questions and one line answers on latitude and longitude

# Teaching Outlines

The chapter discusses how the concept of latitude and longitude is used to 'logically' divide the earth. Each location on the earth can be uniquely located, if we have the latitude and longitude of that place

The implications of these two concepts are very important to understand

## Key Idea - Latitude

### Learning objectives

1. What are latitudes?
2. Why do we need latitudes?
3. What kind of information can we deduce from latitude information?

### Notes for teachers

Latitudes are imaginary curves, they are not real and not lines. The latitudes indicate distance from the equator (which itself is a latitude). Latitude is one factor that influences the weather/climate of a place, generally further the place from the equator, the cooler is the place. (of course, altitude, vegetation, distance from water body are other factors that influence weather, so latitude may by itself not be sufficient to indicate weather).

The Marble educational software can be used to demonstrate Latitudes. By increasing the scale by moving the 'navigation slider',we can increase the map size. We can demonstrate that latitudes are 'parallel'to one another.

### Activity No 1- Using Marble to explore Latitudes

• Estimated Time 1 period
• Materials/ Resources needed Computer/Laptop with Marble educational tool installed. (Ubuntu Kalpavriksha contains Marble) + Projector to show the class

(In Ubuntu, select Applications - Education - Marble)

• Prerequisites/Instructions, if any
• Multimedia resources
1. Video on Earth's tilt causing seasons
• Relevant local connections - people, places and materials
• Process
1. Demonstrate Latitude on the Marble atlas. Move the earth from west to east to simulate the rotation of the earth. Move the Earth 'top down' and 'bottom up' also upside down to show Arctic Circle in the bottom. Explain 'north' and 'south' are only conventions and not 'up' and 'down'
2. Show the 'Precipitation (July) map. Is there any pattern in the rain heavy zones? Does it depend on the Latitudes?
1. (tip - Is there more rain in the northern hemisphere than southern hemisphere? Within the northern hemisphere, is it heavier in some parts, are these related to the latitude of that place?)
2. Why is the rain heavy in the south west coastal part of India (including coastal Karnataka)? Why is there a vertical strip where there is very less rain?
3. Show the 'Precipitation (July) map? Is there any pattern in the rain heavy zones? Does it depend on the Latitudes?
1. While North India around tropic of cancer has good rainfall, why is the same tropic of cancer region in Africa without any rain at all? Tip - This is the Sahara desert region. Is the lack of rain the effect of it being a desert or is it vice versa?)
4. Show the 'Temperature (July) map.
1. Where is the weather hotter - northern or southern hemisphere?
2. In the northern hemisphere, where is it the hottest? Why?
3. Why is it hotter around tropic of cancer in Africa and West Asia, compared to India?
5. Show the 'Temperature (December) map.
1. Where is the weather hotter - northern or southern hemisphere?
2. Why is the southern hemisphere not as hot in December as the northern hemisphere is in July?
3. In December, the northern hemisphere has larger areas which are colder, compared to Southern hemisphere during July. (or the range of temperatures in northern hemisphere is much more than the southern hemisphere). Why?

Basically discuss what are the various factor that affect weather/climate - latitude, vegetation/forest area, coastal region v/s hinterland (distance from sea/water body), altitude, land mass v/s water body etc)

• What questions can you ask

Why do we need the concept of Latitudes?

1. What physical features depend on latitude? Does weather/climate depend on Latitude?
2. What do we mean when we say 'the sun is above Tropic of Cancer on June' and above 'Tropic of Capricorn' in December?
3. Why does Bangalore have peak summer during March-April, while Delhi has peak summer in June?
4. Are Latitudes lines? Are they parallel lines?
5. Are latitudes parallel to one another?
• Assessments - incorporating elements of CCE

The questions in the question corner test the understanding of the Latitude concept and can form part of CCE

• Question Corner
1. Can you find out the latitude of your own village or town using Marble

## Key Idea 2 - Longitude and time zones

What is a longitude? Why do we need Longitudes? How many time zones does India have? How many does USA have? why is there a difference? Russia has the highest number of contiguous time zones (nine). Why?

### Learning objectives

1. Purpose of having longitudes
2. Idea of time zones from longitudes (why do we need time zones?)
3. Longitudes are 'half curves' meeting at the two poles (Latitudes are full curves, encircling the earth at that plane)

### Notes for teachers

Longitudes are not lines but curves Longitudes are imaginary curves, created for enabling tracking of time across the earth

The Marble educational software can be used to demonstrate Longitudes. By increasing the scale by moving the 'navigation slider',we can increase the map size. We can demonstrate that Longitudes are not 'parallel'to one another, but meet at the poles.

### Activity No 1- See video on Time zones and discuss

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• Estimated Time One period
• Materials/ Resources needed Laptop, projector, the video (can be downloaded to computer earlier to avoid bandwidth problems)
• Prerequisites/Instructions, if any
• Multimedia resources - video
• Relevant local connections - people, places and materials
• Process

Show video, explain if needed and discuss the idea and need for time zones

• What questions can you ask
• Assessments - incorporating elements of CCE
• Question Corner
1. If the earth was not rotating on its axis,would there be any need for time zones and longitudes?
2. If the earth was not revolving around the sun, would there be any need for time zones and longitudes?
3. List as many differences between latitude and longitude as possible. Explain these differences

### Activity No 2 - Using Marble educational software to explore Longitudes

• Estimated Time 1 period
• Materials/ Resources needed Computer/Laptop with Marble educational tool installed. (Ubuntu Kalpavriksha contains Marble) + Projector to show the class
• Prerequisites/Instructions, if any
• Relevant local connections - people, places and materials
• Process
1. Demonstrate Longitudes on the Marble atlas. Move the earth from west to east to simulate the rotation of the earth.
2. Explain why different time zones are needed
3. Show the 'Precipitation (July) map? Is there any pattern in the rain heavy zones? Does it depend on the Longitudes?
• What questions can you ask
• Assessments - incorporating elements of CCE - The questions in the question corner test the understanding of the date line concept and can form part of CCE
• Question Corner
1. While the equator (zero degree latitude) is a 'circle', the zero degree longitude (prime meredian passing through Greenwich) is a half circle. Why is this?
2. Are longitudes connected to latitude in any manner?
3. The reason why longitudes help us to understand the movement of day and night (passage of time in our 24 hour clock) is because the earth rotates around the sun in an east-west direction. Is this statement correct? What if the earth were to rotate around a east-west axis (that is from north to south or south to north) instead of a north-south axis? Would longitudes as they are defined now, be of any help?

## Key Idea 3 - International Date Line

Why do we need a International Date Line?

### Learning objectives

To understand need for an arbitrary 'date line' which begins a 'new day' at a artificial 'longitudinal' line. To understand why this line is not 'straight' but changes in many places

### Notes for teachers

This is a very difficult concept to understand and may need a physical simulation with a globe for students to understand.

The idea of time varying across longitudes as well as time zones need to be well understood before coming to date line.

A video explaining the concept of date line

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### Activity No 1 - Using Marble educational software to explore the International Date Line

• Estimated Time 1 period
• Materials/ Resources needed Computer/Laptop with Marble educational tool installed. (Ubuntu Kalpavriksha contains Marble) + Projector to show the class
• Prerequisites/Instructions, if any
• Multimedia resourcesSee video on International date line, shown on this page.
• Relevant local connections - people, places and materials
• Process Demonstrate the International date line on the Marble atlas. Move the earth from west to east to simulate the rotation of the earth. Explain why the date line is needed and why it is not 'straight'
• What questions can you ask
• Assessments - incorporating elements of CCEThe questions in the question corner test the understanding of the date line concept and can form part of CCE
• Question Corner
1. Can a plane flying across the earth, move from Monday at the departing location to Tuesday at the arriving location?
2. Can a plane flying across the earth, move from Tuesday at the departing location to Monday at the arriving location?
3. Can any two places on Earth be on two different (consecutive) days?
4. Can any two places on Earth be on two different days, which are not consecutive?
5. The date line is to a large extent over the ocean (water body) and very less on Land. What is the benefit of this?

# Project Ideas

1. Have any countries shifted from one side of the international date line to the other? Why?
2. Mobile phones can have software application to record the latitude and longitude information of a place. For eg OSM Tracker on a Android phone can record the 'lat long' information about a place, and even record a track, such as a road. Try recording using this on a cell phone. You can also upload this information on a digital map on the Internet such as the openstreetmap (http://openstreetmap.org). See for instance schools recorded on openstreetmap in Yadgir taluka (search Yadgir on openstreetmap.org). You can also see http://kalike.org/map/ and select schools in top right box. You can map important places in your place - shops, hospitals, government offices etc using OSM tracker and upload on openstreetmaps.org
3. Identify the history of longitudes. See https://en.wikipedia.org/wiki/History_of_longitude

# Community Based Project

Discuss with your family members about time zones. If any have travelled abroad (to countries in other time zones), ask them their experiences. Have they suffered a 'jet lag'?