Mapping Earth: Continents and Oceans - Second Grade Science
To understand the giant planet we live on, scientists, navigators, and explorers create scaled models called globes and flat representations called maps. Earth is an enormous sphere, and its surface is divided into seven massive landmasses called continents and five vast saltwater expanses called oceans. By learning how to read maps, identify cardinal directions, use a compass rose, and interpret a map key, you can navigate your way across neighborhoods, countries, and entire continents!
Globes vs. Maps
Scientists use both round globes and flat paper maps to represent Earth, and each has its own advantages.
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| GLOBE VS. MAP |
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| SPHERICAL GLOBE FLAT MAP |
| - True 3D model of Earth - 2D flat drawing of Earth |
| - Accurate shapes, sizes, distances - Distorts polar shapes |
| - Shows Earth's axis of rotation - Folds easily; portable |
| - Cannot see whole planet at once - Can show entire world at once|
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The Seven Continents
A continent is one of Earth's seven largest continuous landmasses. Nearly all humans and land animals live on these seven continents.
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| THE SEVEN CONTINENTS |
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| 1. ASIA ----> Largest continent in land & population |
| 2. AFRICA ----> Second largest; Sahara Desert & Nile River|
| 3. NORTH AMERICA ----> Home to Canada, United States, and Mexico |
| 4. SOUTH AMERICA ----> Home to Amazon Rainforest & Andes Mtns |
| 5. ANTARCTICA ----> Freezing southernmost continent of ice |
| 6. EUROPE ----> Connected to Asia; densely populated |
| 7. AUSTRALIA ----> Smallest continent; an island continent |
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[ North America ] --- [ Europe ] --- [ Asia ]
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[ South America ] [ Africa ] |
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[ Australia ]
[ Antarctica ]
Exploring the Continents
Asia: The largest continent, home to more than half the world's human population and Mount Everest. Africa: Known for the vast Sahara Desert, the Nile River, and vast savannas filled with elephants and lions. North America: Stretches from the icy Arctic tundra of Alaska and Canada down through temperate forests to Mexico. South America: Houses the world's largest river by volume, the Amazon, and the longest mountain range, the Andes. Antarctica: Encircling the South Pole, it is the coldest, windiest, and driest continent, covered in ice sheets. Europe: Separated from Asia by the Ural Mountains, it features rich agricultural plains, peninsulas, and historic cities. Australia: Completely surrounded by water, it is home to unique marsupial wildlife like kangaroos and koalas.
The Five Oceans
While continents divide the land, oceans divide the salty water. All five oceans connect into one continuous global body of water.
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| THE FIVE OCEANS |
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| 1. PACIFIC OCEAN ----> Largest & deepest; covers 1/3 of Earth |
| 2. ATLANTIC OCEAN ----> Second largest; separates Americas & Euro |
| 3. INDIAN OCEAN ----> Warmest ocean; touches Africa, Asia, Aust |
| 4. SOUTHERN OCEAN ----> Encircles freezing Antarctica |
| 5. ARCTIC OCEAN ----> Smallest & shallowest; surrounds North Pole|
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Essential Map Tools
Cartographers (mapmakers) include special symbols and guides on maps to help readers determine direction, distance, and features.
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| ESSENTIAL MAP TOOLS |
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| THE COMPASS ROSE THE MAP KEY / LEGEND |
| N |
| | === Road |
| W---+---E /\ Mountain |
| | ~~~ River |
| S [P] Park |
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| Cardinal Directions: North, South, East, West. Explains symbols! |
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The Compass Rose and Cardinal Directions
The compass rose is a printed figure that displays orientation: North (N): Points toward the North Pole (usually the top of the map). South (S): Points toward the South Pole (the bottom of the map). East (E): Points to the right side of the map. West (W): Points to the left side of the map. Remember the mnemonic: "Never Eat Soggy Waffles" (North, East, South, West)!
The Map Key (Legend)
A map key explains what special symbols, line styles, and colors mean: Blue: Represents water (oceans, lakes, rivers). Green: Represents low-elevation plains, forests, or parks. Brown / Triangles: Represents mountain ranges and peaks. Dotted Lines: Mark political borders between states or countries.
Chapter Review Exercises
Question 1: What is the primary advantage of using a spherical globe compared to a flat paper map?
Question 2: Name the seven continents of the world in order of size, beginning with the largest.
Question 3: Which ocean is the largest and deepest on Earth, and which ocean surrounds the frozen continent of Antarctica?
Question 4: What are the four cardinal directions shown on a compass rose, and what is the purpose of a map key (legend)?
Solutions and Explanations
Solution 1: A spherical globe is a true three-dimensional model of Earth that displays continents and oceans with accurate relative sizes, shapes, and distances without the distortion found on flat maps.
Solution 2: The seven continents from largest to smallest are Asia, Africa, North America, South America, Antarctica, Europe, and Australia.
Solution 3: The Pacific Ocean is the largest and deepest ocean on Earth. The Southern Ocean (also called the Antarctic Ocean) surrounds the continent of Antarctica.
Solution 4: The four cardinal directions are North, South, East, and West. The map key (or legend) is an explanatory box that explains the meaning of all symbols, line patterns, and colors used across the map.