Use data on landforms, climate, population, economics and culture to determine regions within the Eastern Hemisphere, and explain how changing the criterion changes the region

Learning goal: Explain how regions within the Eastern Hemisphere can be determined using data related to various criteria, including landforms, climate, population, economics and culture. This lesson teaches Ohio's 2026 social studies standard for Grade 6, published in July 2026. The Ohio Department of Education and Workforce anticipates that districts will begin implementing the 2026 standards in the 2027-28 school year.

What a region is. A region is an area that shares one or more characteristics that make it different from the areas around it. Geographers create regions to organize a complicated world. The characteristic they choose is the criterion (plural: criteria). To determine a region, a geographer collects data, facts and measurements such as elevation, rainfall or the language people speak, and draws the boundary where the data change. The Eastern Hemisphere is the half of Earth east of the Prime Meridian and west of the 180° line of longitude. In school geography the term usually means the continents of Europe, Africa, Asia and Australia as wholes, even though parts of western Africa and western Europe lie just west of the Prime Meridian.

Criterion 1: landforms. Landforms are the shapes of Earth's surface: mountains, plateaus, plains and valleys. Elevation data define landform regions. The Himalayas in South Asia are a mountain region that contains the world's highest peak, Mount Everest, nearly 8,850 meters (about 29,000 feet) above sea level. The North European Plain is a region of low, fairly flat land stretching from France and Belgium through the Netherlands, Germany and Poland into Russia. The Great Rift Valley is a long system of valleys in East Africa, running roughly from Ethiopia south toward Mozambique, formed where Earth's crust is pulling apart; deep lakes such as Lake Tanganyika and Lake Malawi lie in it. The boundary of a landform region follows changes in elevation and slope.

Criterion 2: climate. Climate is the usual pattern of temperature and precipitation in a place over many years. Rainfall and temperature data define climate regions. The Sahara in northern Africa is the largest hot desert on Earth; much of it receives less than about 100 millimeters (4 inches) of rain in a typical year. South of it lies the Sahel, a belt of semi-dry grassland stretching across Africa from Senegal and Mauritania in the west toward Sudan in the east. The Sahel is a transition zone, an area where one region gradually changes into another. Geographers often define it by rainfall, for example as the belt receiving roughly 200 to 600 millimeters a year, though definitions differ. Because climate describes many years, the Sahel's edges are drawn from long-term average rainfall; in any single wet or dry year the actual rainfall belt moves north or south, which is one reason the edge is a zone, not a line. The Mediterranean climate region has hot, dry summers and mild, rainy winters; it surrounds the Mediterranean Sea and also appears around Cape Town in South Africa and in southwestern Australia, showing that a region does not have to be one connected area. Monsoon Asia is defined by seasonal winds: in much of India, Bangladesh and Southeast Asia, the summer monsoon brings the greater part of the year's rain in a few months.

Criterion 3: population. Population density is the number of people per unit of area; it is calculated by dividing population by land area. Population data show where people cluster. In Egypt, the great majority of people live on a small share of the country's land, along the Nile valley and in the Nile delta, because the rest is desert. The Ganges plain of northern India and Bangladesh is one of the most densely populated farming regions in the world. East Asia's coastal plains and river valleys in eastern China, Korea and Japan are crowded, while Siberia, the huge northern part of Russia, and the high Tibetan Plateau in western China have very few people. A population region's boundary follows changes in density.

Criterion 4: economics. Economic data describe how people earn a living: what they produce, sell and trade. Countries around the Persian Gulf, such as Saudi Arabia, Kuwait, Qatar and the United Arab Emirates, form an economic region of oil and natural gas exporters; for several of them, oil and gas make up the greater part of the value of their exports. The Pearl River Delta in southern China, around cities such as Guangzhou and Shenzhen, is a manufacturing region that makes electronics, clothing and many other goods sold around the world. Export and industry data draw these boundaries.

Criterion 5: culture. Culture is the way of life of a group: language, religion, customs, food and arts. Language data define the Arab world, the countries where Arabic is the main language, stretching from Morocco and Mauritania in North and West Africa to Iraq and the Arabian Peninsula in Southwest Asia. Francophone Africa is made up of countries where French is an official or widely used language, largely a result of French and Belgian colonial rule; examples include Senegal, Côte d'Ivoire and the Democratic Republic of the Congo.

Changing the criterion changes the boundary. The same place belongs to different regions depending on the criterion. Morocco is part of the Arab world (culture), part of the Mediterranean climate region along its northern shore and at the edge of the Sahara in its south (climate), and a country where French is widely used (culture again). Regions overlap, and their edges are often transition zones rather than sharp lines.

A fully worked model: drawing a climate boundary from data. A geographer has long-term average yearly rainfall (for example, 30-year averages) from hypothetical weather stations placed on a line running south from the central Sahara toward the Gulf of Guinea. Rule chosen: under 200 millimeters a year = desert; 200 to 600 = Sahel; over 600 = wetter savanna and forest. Stations: 20, 150, 350, 550, 900 and 1,400 millimeters. Step 1: the first two are desert. Step 2: 350 and 550 are Sahel. Step 3: 900 and 1,400 are wetter. Step 4: draw the desert–Sahel boundary between the 150 and 350 stations and the Sahel–savanna boundary between 550 and 900. Step 5: test the rule. If the geographer had used 100 millimeters as the desert limit instead, the 150 station would move into the Sahel, and the boundary would shift north. The data are the same; the criterion changed the region.

The misconception. Students often think regions are fixed, natural things with exact borders, like country lines on a map. Regions are tools geographers build from data. A different criterion, or a different threshold for the same criterion, produces a different region, and real boundaries are usually gradual transition zones.

Worked example 1 — calculate population density (hypothetical data): Task: a hypothetical desert country with a river valley has 100,000,000 people and 1,000,000 square kilometers of land. The valley covers 50,000 square kilometers and holds 95,000,000 people. Find the density of the country, the valley and the rest. Solution: whole country 100,000,000 ÷ 1,000,000 = 100 people per square kilometer. Valley 95,000,000 ÷ 50,000 = 1,900 per square kilometer. Rest of the country: 5,000,000 people ÷ 950,000 square kilometers ≈ 5.3 per square kilometer. The valley covers 5% of the land (50,000 ÷ 1,000,000) but holds 95% of the people. The average of 100 hides two very different regions; a population region should be drawn around the valley. This pattern resembles, in a simplified way, how Egypt's people are concentrated along the Nile.

Worked example 2 — one place, five criteria: Task: use each criterion to place northern India in a region. Solution: landforms, the Ganges plain, a low river plain bordered on the north by the Himalayas; climate, monsoon Asia, because most of the rain arrives in the summer monsoon; population, a very densely populated region; economics, a large farming region (the student would check export or crop data to be more specific); culture, a region where Hindi and related languages are widely spoken. The five regions have different boundaries: the Himalayas region ends at the mountain foothills, while monsoon Asia extends far beyond India into Southeast Asia.

Worked example 3 — overlap and transition zones: Task: explain why the Sahel is a good example of a transition zone. Solution: rainfall data show a gradual change from the dry Sahara in the north to wetter savanna in the south, so no sharp line exists; geographers choose rainfall thresholds, and different thresholds put the edge in different places. Rainfall in single years also moves back and forth, so the edge drawn from long-term averages is best shown as a zone. It overlaps other regions: several Sahel countries, such as Senegal, are also in Francophone Africa, so a single place belongs to a climate region and a cultural region at the same time.

Regions overlay map (representation task): On an outline map of the Eastern Hemisphere, draw five regions from the lesson, one for each criterion (for example, the Himalayas, the Sahel, the Nile valley population cluster, the Persian Gulf oil exporters and the Arab world), each in a different color or pattern with a key. For each, write the data the boundary is based on. Circle two places where regions overlap and shade one transition zone.

Independent performance: Write a 250–350 word explanation titled "One place, many regions" about a real place in the Eastern Hemisphere you choose. Success criteria: (1) you define region, criterion and transition zone; (2) you place your chosen place in at least four regions using four different criteria from landforms, climate, population, economics and culture; (3) you name the kind of data that determines each region's boundary; (4) you explain, with an example, how changing the criterion or the threshold changes the boundary; (5) you hedge any number you are not sure of and label any invented data as hypothetical.