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Most of the Earth's surface is water; the land is seven continents and the water five oceans, each with a name in every language.
Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.
You will tell land from water on a globe, say which there is more of, and name continents and oceans from a description.
You know that a place sits inside a bigger place, and that a continent is the biggest of those. This lesson is about what a continent sits in: the water, which covers most of the ball and comes in its own few big pieces. You will also subtract to compare two counts.
| Term | What it means |
|---|---|
| Globe | A model of the Earth shaped like a ball. |
| Continent | One of the seven great pieces of land. |
| Ocean | One of the five great pieces of salt water. |
| Ice sheet | A thick layer of ice lying on land, as on Antarctica. |
| Sea ice | Ice floating on the ocean, as around the North Pole. |
The Earth is a ball, and a globe is a small model of it. A globe is worth having because it is the only picture of the Earth that stretches nothing: a ball cannot be laid out flat without something being pulled out of shape, so every flat map of the whole world has stretched something somewhere.
Look at a globe and the first thing to notice is the color. Most of the surface is water, roughly two or three times as much water as land. Turn it any way you like and there is more blue in front of you than green.
The land comes in a few great pieces called continents, seven of them. The water comes in a few great pieces called oceans, five of them. Each has a name, and the name is different in different languages: Africa in English, África in Spanish and Portuguese.
Another way: story
If you spun a globe and stopped it with one finger without looking, you would land on water far more often than on land. Try it ten times and count.
Another way: example
A world map on a page looks much greener than a globe does, because the land is where all the names are printed and the eye goes to the writing. The globe is telling the truth and the page is not lying; your eye is fooling you.
A physical feature belongs to the natural setting: a stream, hill, soil or shoreline. A human feature is made or changed by people: a road, bridge, building or planted playing field. A managed park can contain both. Do not decide only by color: green grass might be a maintained lawn. Compare the same kinds of feature at the same local scale. In an invented example, Pine Lane and Lake Lane each have a pond. Pine Lane has a paved crossing while Lake Lane has a muddy path. The water is a similarity; the crossings are a difference. That difference could affect travel, but to say which crossing is usable today we need a dated observation. A map of a whole country is too general to settle this neighborhood question.
Here are the great pieces of land and water, biggest first.
| Continents (land) | Oceans (water) |
|---|---|
| Asia | the Pacific Ocean |
| Africa | the Atlantic Ocean |
| North America | the Indian Ocean |
| South America | the Southern Ocean |
| Antarctica | the Arctic Ocean |
| Europe | |
| Australia |
The United States is on North America, and it touches three oceans: the Atlantic on the east coast, the Pacific on the west coast and in Hawaii, and the Arctic at the top of Alaska.
Scientists have measured it: about 71 out of every 100 parts of the Earth's surface are water, and about 29 are land. That is roughly seven parts water for every three parts land.
You can see it for yourself. Spin a globe and stop it with a finger without looking, ten times. You will usually land on water about seven times. The more times you try, the closer your count gets to seven out of ten.
A flat map of the whole world has to stretch the round Earth to make it lie flat, like peeling an orange and pressing the peel onto a table. Something always tears or stretches. Many world maps make lands near the poles, such as Greenland and Alaska, look far bigger than they are.
A globe is round like the Earth, so nothing is stretched. Sizes and shapes on a globe are true, which is why this lesson uses one.
The white caps at the top and bottom of a globe are ice, but they sit on different things. At the bottom, a thick ice sheet lies on the land of Antarctica, a continent. At the top, around the North Pole, most of the ice is frozen sea floating on the Arctic Ocean.
So the same white means land underneath at one end and water underneath at the other. To answer land or water?, ask what lies under the ice.
Every continent and ocean has a name in every language. English says North America; Spanish says América del Norte; Portuguese says América do Norte. They are the same place with different names.
Many of the names are old. Pacific means peaceful, a name given by a sailor who crossed it in calm weather. Arctic comes from an old Greek word for the bear, a group of stars seen in the northern sky.
A count only means something when it is compared. If a class spins a globe ten times and lands on water seven times, then land came up ten minus seven, which is three times.
Seven minus three is four, so water came up four more times than land. That difference is the evidence: water is not just a little more common than land, but more than twice as common.
Checking an answer. Land stops plus water stops must equal all the stops. If they do not add up, a count has slipped.
Reading the colors is allowed because the globe's key says green is land and blue is water. Using a place's name is allowed because continent and ocean already say which kind of thing each is.
Finding the land stops by subtracting is allowed because every stop is either land or water, never both and never neither, so the two counts together make all the stops.
The most common slip is thinking there is about as much land as water. Another is calling all the white ice land, forgetting that the Arctic ice floats on the sea.
A third is choosing one piece of land when a question asks for all of it. A fourth is treating the invented shapes on this course's globe as the real continents.
On December 7, 1972, the astronauts of Apollo 17 took a photograph of the whole Earth from about 18,000 miles away, on their way to the Moon. It is called The Blue Marble, and it became one of the most famous photographs ever taken.
The name says what the picture shows: a ball that is mostly blue. Africa and the Arabian Peninsula show brown and green near the middle, and the ice of Antarctica shines white at the bottom, but the Atlantic and Indian Oceans take up most of the picture, with white swirls of cloud over them.
NASA has taken many more pictures of the whole Earth since then, from satellites, and they all tell the same story as a globe. Whichever side of the planet faces the camera, there is more ocean than land. The side that faces the Pacific Ocean is almost all water, with only a few small islands.
The state of Hawaii is a chain of islands in the middle of the Pacific Ocean, about 2,400 miles from California. A family flying there from Los Angeles looks out of the airplane window for about five and a half hours and sees nothing but blue water.
The Pacific is the largest ocean on Earth. It covers about a third of the whole surface, more than all the land on every continent put together. On a globe, if you turn it so Hawaii faces you, you see almost nothing but water, with the edges of Asia, Australia and the Americas just peeking around the sides.
The first people to reach Hawaii, the Polynesians, sailed there in canoes many hundreds of years ago. They crossed thousands of miles of open ocean by reading the stars, the waves and the flight of birds, long before anyone had a globe to show how much water lay in between.
The first is thinking there is about as much land as water, or more. There is not, and the reason it looks that way is a page rather than the world: on a printed map all the names, the colors and the borders are on the land, so that is where the eye goes.
The second is calling the white caps land. They are ice. Ice at the top of the globe is mostly floating on the sea; ice at the bottom is mostly lying on Antarctica, which is land. Same white, two different answers, and the way to tell is to ask what is underneath.
The third is expecting the land shapes on this drawing to be the real continents. They are invented, and the map register says so. Drawing the real ones at this size would mean drawing coastlines and then borders, and there are borders in the world that people argue about, which is a thing to study later and not a thing to be marked right or wrong on now.
Antarctica is one of the seven continents. Name what a continent is.
$\text{land}$
A great piece of land.
Say what covers most of it.
$\text{a thick ice sheet}$
Frozen water on top.
Ask what is underneath the ice.
$\text{rock and ground}$
The continent itself.
Answer the question.
$\text{land, with ice on it}$
The ice does not change the ground.
Turn the globe slowly and watch what goes past.
$\text{mostly blue}$
Every time.
Look for a mostly green side.
$\text{there is none}$
No way of turning finds one.
Compare with the measurement.
$71 \text{ water}, 29 \text{ land}$
Out of every hundred parts.
Put it simply.
$\text{about seven water to three land}$
Roughly.
Explain why a page looks greener.
$\text{names are printed on land}$
The eye goes to the writing.
A class spins a globe $10$ times. It stops on water $7$ times. Find the land stops.
$10 - 7 = 3$
Every stop is land or water.
Compare water with land.
$7 - 3 = 4$
Four more on water.
Check the counts add up.
$7 + 3 = 10$
All the stops.
Compare with the measurement.
$\text{about } 7 \text{ in } 10$
Close to 71 in 100.
Say what the count shows.
$\text{more than twice as much water}$
Seven is more than twice three.
Say how to make it fairer.
$\text{spin many more times}$
A few spins can be lucky.
Read the kind in the name.
$\text{an ocean}$
The name says so.
Say what an ocean is.
$\text{water}$
One of the five.
Answer the question.
Turn a globe slowly and watch the colors go past. Which of these is true of the Earth's surface?
Complete the worked solution: a class spins a globe and stops it with one finger, without looking, $20$ times. The finger lands on water $14$ times. How many times did it land on land, and how many more times on water than on land?
Find the land stops.
$\text{all stops} - \text{water stops} =$ l
The stops that were not water.
Compare water with land.
$\text{water stops} - \text{land stops} =$ m
How many more on water.
Say what the counts suggest.
$\text{more water than land}$
A finger lands where there is most.
Say why to spin many times.
$\text{a few spins can be lucky}$
More spins give a fairer count.
Now the water. Three oceans, three clues, and the clues were not all in the lesson.
| the Pacific Ocean | the Southern Ocean | the Arctic Ocean | |
|---|---|---|---|
| the largest ocean of all | |||
| the ocean that runs all the way around Antarctica | |||
| the smallest ocean, under the ice at the top of the globe |
Three continents, three clues. Match each clue to the continent it describes.
| Antarctica | Australia | Asia | |
|---|---|---|---|
| the continent covered in ice, with no countries on it | |||
| the continent that is also a single country | |||
| the largest continent of all |
On this globe the green shapes are land, the blue is water, and the two white caps are ice floating on the sea and lying on the land at the very top and bottom. Click **all** the land.
This task has no paper form; do it on a device.
Now the other way around. Two parts of this globe are open blue water: one between the green shape in the upper-left and the small oval below it, and one below the green shape on the right. Click both pieces of water.
This task has no paper form; do it on a device.
Three real names from a globe. Say whether each one is land or water.
| Land or water? | |
|---|---|
| Asia | |
| the Pacific Ocean | |
| Antarctica |
Two invented neighborhoods each have a stream and 3 low hills. Eastbank also has a bridge and a bus stop; Westbank has a footpath but no bridge or bus stop. Read the field-note analysis below. Select the two observations needed to compare physical and human features, AND the statement that correctly limits what they show. Leave unsupported claims unmarked.
This task has no paper form; do it on a device.
Lesson test: one question per skill, one attempt each, no hints. Your answers are checked when you submit.
A survey describes three surfaces in an invented polar region. Classify the underlying surface as land or water. Ice cover and buildings can be misleading, so use what is beneath them.
| Underlying surface: land or water | |
|---|---|
| a continent covered by snow | |
| seawater beneath an ice floe | |
| a high rocky island |
You can tell land from water on a globe. Tell somebody why Antarctica counts as land even though it is covered in ice.
21. Your turn: the Indian Ocean — is that land or water?, step 3
$\text{the Indian Ocean is water}$
No ice to check here.