What If? Lab
What if the wind stopped blowing?
Wind is air on the move. It dries puddles, carries seeds and pushes sailboats. What if the air stood still? Let's imagine it with Olly!
Wind is air rushing from places of high pressure to places of low pressure. It carries heat, water and weather around the world, lifts seeds to new homes and has pushed sailing ships across oceans. Imagine all the air going still, and follow what might change.
NOAA describes global atmospheric circulation as the movement of air that carries thermal energy and storm systems over Earth's surface, while jet streams steer weather systems and move heat and moisture. This thought experiment stops the wind and reasons about what might change for weather, plants and travel.
The big question
Wind is air that moves. You can feel it on your face.
What if the wind stopped, all over the world? What might change?
You cannot see the wind, but you can feel it push on your face and watch it bend the trees. Wind is simply air on the move.
What if, one day, all the air on Earth stood perfectly still? In this thought experiment you can follow three paths: what still air might mean where you live, what might happen to the weather, and what might happen to seeds and sailing ships.
Wind is air on the move, driven by pressure differences that NOAA traces back to temperature differences from uneven heating of Earth by the Sun.
This thought experiment removes that motion entirely and asks what might change for local conditions, for the large-scale transport of heat, moisture and weather systems, and for living things and people that depend on moving air. It cannot say how the wind could stop; it reasons only from what wind does today.
Explore the idea
Make a prediction
After rain, what does wind do to a wet road?
After a rainstorm, what does wind do to a wet road?
According to NOAA, how does a surface wind affect a wet road after rain?
- It helps the road dry faster
- It keeps the road wet longer
- It makes no difference
-
Established fact
Wind is moving air. It carries warmth, weather and seeds.
Wind is air moving from high to low pressure; it carries heat, weather systems and wind-borne seeds (NOAA, Columbus State University).
Pressure differences from uneven solar heating drive the circulation and jet streams that move heat, moisture and weather systems (NOAA).
-
An idea scientists discuss
A world with no wind is pretend. We imagine what might happen.
The wind won't stop everywhere. What might happen without it is an idea built from what wind does today.
Every consequence of still air here is reasoned from present processes and might differ greatly in reality.
-
Established fact
Wind happens when air moves from one place to another.
Air moves from areas of high pressure to areas of low pressure. The bigger the difference, the faster the wind.
Wind is air moving from high to low pressure; speed rises with the pressure difference, which comes from uneven solar heating (NOAA).
-
Established fact
A wet road dries faster when it is windy.
Surface winds increase evaporation: after a rainstorm, the road dries faster if it is windy.
Surface winds increase evaporation from wet surfaces (NOAA NESDIS).
-
Established fact
Wind carries smoke and dust away and spreads it out.
Wind carries pollution away from where it is made, and swirling air mixes it and spreads it out.
In the boundary layer, wind transports pollutants from their sources and turbulence mixes and dilutes them (NOAA Physical Sciences Laboratory).
-
An idea scientists discuss
With no wind, puddles and wet clothes might dry more slowly.
With no wind, wet things might dry more slowly, and smoke and dust might stay close to where they are made.
Without wind, evaporation might slow and pollutants might accumulate near their sources; how much is beyond this experiment.
-
Established fact
Fast winds high in the sky push the weather along.
Jet streams carry weather systems from place to place, usually from west to east. A weather system far from a jet stream can stay in one place.
Jet streams typically move storms and other weather systems from west to east; a system far from a jet stream might stay in one place (NOAA NESDIS).
-
Established fact
Moving air carries warmth around the world.
The movement of air around the planet carries heat and storms over Earth's surface.
Global atmospheric circulation explains how thermal energy and storm systems move over Earth's surface, organized into Hadley, Ferrel and polar cells (NOAA JetStream).
-
An idea scientists discuss
With no wind, sunny days or rainy days might stay in one place.
With no wind, weather might stop traveling, so one place might keep the same weather for a long time.
Halting circulation might leave weather systems stationary and stop the poleward transport of heat and moisture; the outcome cannot be estimated here.
-
Established fact
Some seeds have fluffy hairs or thin wings to ride the wind.
Seeds that travel by wind are small and lightweight, with tiny hairs or paper-thin wings, like dandelion and maple seeds.
Wind-dispersed seeds are small and light, with hairs or thin wings that keep them aloft, as in dandelions and maples (Columbus State University, Oxbow Meadows).
-
Established fact
Sailors use the trade winds to help ships cross the sea.
The trade winds helped early sailing ships reach the Americas, and commercial ships still use them to speed up their voyages.
The trade winds and the currents they drive helped early sailing ships reach the Americas, and commercial ships still use them (NOAA Ocean Service).
-
Established fact
Near the middle of the Earth, there is a calm place sailors call the doldrums.
In the doldrums, near the equator, there is often little wind at the surface, and sailing ships have been stuck there for weeks.
In the ITCZ, air circulates upward, so surface wind is often light and sailing ships can be becalmed for weeks (NOAA Ocean Service).
-
An idea scientists discuss
With no wind, seeds might drop near their parent plant, and sailboats might stay still.
With no wind, wind-carried seeds might land right beside their parent plant, and sailing ships might sit still as if in the doldrums.
Without wind, wind-dispersed plants might spread far less and sail-powered travel might stop; ecological effects cannot be estimated here.
In our world
The Sun warms some places more than others.
Warm air rises. Air rushes from crowded places to roomier places. That rush of air is the wind!
NOAA explains that the main cause of wind is a difference in temperature. The Sun warms Earth unevenly, because sunlight hits different places at different angles and because oceans, mountains and other features make some places warmer than others.
Warm air spreads out and rises, leaving an area of low pressure behind. Air always moves from high pressure toward low pressure, and the bigger the difference, the faster it rushes. That rush of air is the wind we feel.
NOAA: when gases warm, their molecules move faster, spread out and rise; colder air sinks. Uneven solar heating therefore creates pockets of high and low pressure, and air moves from high to low pressure, faster when the pressure difference is larger.
On a planet with no rotation, tilt or surface water, NOAA notes, a single loop might carry warm air from the equator to the poles and back. Earth's rotation, tilt and uneven land and water break this into three circulation cells in each hemisphere: the Hadley, Ferrel and polar cells. George Hadley proposed the single-cell idea in 1735.
Imagine still air
Let's pretend all the wind stops.
Puddles might dry more slowly. Seeds might drop close to home. Let's find out why!
Now imagine all the air on Earth staying still. Wet roads and laundry might take longer to dry, because wind helps water evaporate. Smoke and dust might hang near where they are made instead of drifting away.
The weather might change too: the same clouds or sunshine might stay over one place for a long time. Seeds that ride the wind might fall close to their parent plant, and sailboats might sit still. These are ideas: we reason from what the wind does today.
With no wind, the circulation that NOAA says carries thermal energy and storm systems might cease, so tropical heat and moisture might no longer be spread toward the poles by the air. Weather systems that jet streams steer might stall.
Locally, evaporation might slow and pollutants might no longer be carried away and diluted. Wind-dispersed plants might lose their main way of reaching new ground. These are reasoned ideas, not predictions; a real atmosphere heated unevenly by the Sun cannot stay still.
Why wind matters
Wind carries warm air and cool air around the world.
High in the sky, very fast winds push the weather along. Wind also helps wet things dry.
NOAA says the movement of air around the planet explains how heat and storm systems travel over Earth's surface. High up, about five to nine miles above the ground, narrow bands of fast wind called jet streams carry weather systems from place to place, usually from west to east.
Wind also works close to the ground. NOAA notes that surface winds increase evaporation: after a rainstorm, a road dries faster when it is windy. And wind carries smoke and dust away from where they are made and mixes them into the air.
NOAA's education pages state that jet streams steer weather systems and transfer heat and moisture around the globe. Earth has four primary jet streams, two polar and two subtropical, averaging about 110 mph and reaching 250 mph or more, usually in polar jets in winter. NOAA adds that a weather system far from a jet stream might stay in one place.
Near the surface, wind raises evaporation, and NOAA's Physical Sciences Laboratory describes wind transporting pollutants from their sources while turbulence mixes and dilutes them.
Wind at work today
Some seeds have fluffy hairs or thin wings. The wind carries them away.
Ships still use the trade winds to help them cross the sea.
Plants use the wind. A Columbus State University nature center explains that wind-carried seeds are small and light, with tiny hairs or paper-thin wings, like dandelion and maple seeds.
People use the wind too. NOAA says the trade winds, the prevailing easterly winds near the equator, helped early sailing ships cross to the Americas, and commercial ships still use them today. Near the equator, sailors also know a calm belt called the doldrums, where ships have sometimes been stuck on windless water for weeks.
Cornell University researchers reported in 2025 that dandelions respond to wind direction when releasing seeds: a seed pushed toward the ground needs almost five times the force to release as one pushed upward.
NOAA describes the trade winds as prevailing easterlies between about 30° N and 30° S that early sailing ships used to reach the Americas and that commercial ships still use. Where the trades meet, in the Inter-Tropical Convergence Zone or doldrums, air rises and there is often little surface wind, which can becalm ships for weeks. The doldrums are a small taste of still air.
Amazing facts
-
Sailing ships sometimes waited for weeks in a calm place called the doldrums.
Near the equator, the doldrums can becalm sailing ships for weeks, because the air there mostly rises instead of blowing along the surface.
In the ITCZ, air circulates upward, so surface winds are often light enough to becalm sailing ships for weeks (NOAA).
-
Airplanes flying with a jet stream get a speedy push.
An airplane flying from west to east can usually make a trip faster than one flying the same route east to west, thanks to the jet stream.
Because jet streams blow from west to east in the mid to upper troposphere, eastbound flights can get a boost and generally finish sooner than westbound ones (NOAA).
-
Dandelions let their seeds go more easily when the wind lifts them up.
Cornell scientists found that a dandelion seed pushed toward the ground needs almost five times as much force to let go as a seed pushed upward.
A 2025 Cornell study found dandelion seeds need almost five times more force to detach when pushed downward than upward, and that their tiny stalks are asymmetrical.
Words to know
- wind
- air that moves from one place to another
- air pressure
- how hard the air pushes on things around it
- evaporation
- when liquid water turns into a gas and goes into the air
- jet stream
- a narrow band of very fast wind high above the ground
- trade winds
- the usual winds that blow from east to west on both sides of the equator
- doldrums
- a belt near the equator where there is often very little wind at the surface
Discovery challenge
-
Wind is air on the move. Which way does the air rush?
Which way does air move to make the wind?
In which direction does air flow to produce wind?
- From high pressure to low pressure
- From low pressure to high pressure
- Straight up into space
Show the answer
From high pressure to low pressure
From high pressure to low pressure, where there is room.
From high pressure to low pressure. The bigger the difference, the faster the wind.
From high to low pressure, faster when the pressure difference is larger (NOAA).
-
Which seeds can fly away on the wind?
Which of these seeds is built to travel by wind?
Which seed is dispersed mainly by wind?
- Dandelion seeds
- Coconuts
- Acorns
Show the answer
Dandelion seeds
Dandelion seeds! Their fluffy hairs help them float.
Dandelion seeds, which have tiny hairs. Coconuts float on water, and acorns drop from oak trees.
Dandelions, with plumed seeds; coconuts travel by water and acorns fall by gravity (Columbus State University).
-
What do sailors call the calm place near the middle of the Earth?
What do sailors call the calm belt near the equator where ships can get stuck?
Sailors' name for the Inter-Tropical Convergence Zone, where ships can be becalmed, is…
- The doldrums
- The jet stream
- The trade winds
Show the answer
The doldrums
The doldrums! Sometimes there is hardly any wind there.
The doldrums, where sailing ships have waited for weeks for wind.
…the doldrums, where surface wind is often light (NOAA).
-
Jet streams are fast winds high in the sky. About how fast do they blow?
About how fast do jet streams blow, on average?
According to NOAA, the average speed of a jet stream is about…
- About 110 miles per hour
- About 10 miles per hour
- About 1,000 miles per hour
Show the answer
About 110 miles per hour
About 110 miles per hour. That is very fast!
About 110 miles per hour, and sometimes 250 or more.
…110 mph on average, exceeding 250 mph mostly in winter polar jets (NOAA).
Experiments to try
- Watch What If? Lab What if we could see the wind? Wind is moving air, and air is invisible. So people watch what the wind moves: smoke, leaves, flags, clouds and kites. Scientists even make wind maps from satellite pictures. Imagine the wind suddenly becoming visible, and follow the swirls, maps and kites that might appear.
- Watch What If? Lab What if lightning never struck? Lightning is a giant electric spark from a storm cloud. It's powerful, but it also does useful jobs: it turns some nitrogen in the air into plant food, and its fires help some forests renew. Imagine a world where lightning never struck, and see what would change and what would carry on.
- Watch What If? Lab What if earthquakes could be predicted? No scientist has ever predicted a major earthquake, and USGS says nobody knows how. What scientists can do is work out the chances of a quake in an area, send a warning seconds after one starts, and help design buildings that shake less. Imagine we could know the exact day, and follow what might change.
- Watch What If? Lab What if waves had no wind? Most ocean waves are made by wind blowing over the water. So what if the wind stopped everywhere? New waves would stop forming, but swells from earlier storms could keep rolling in for a while. And the tide would still come in and go out, because tides are made by the pull of the Moon and the Sun, not by wind.
- Watch Try it What If? Lab What if the wind blew twice as hard? A wind turbine turns moving air into electricity. In our model, a gentle 5 m/s wind lets a big turbine make about 0.15 megawatts. Double the wind to 10 m/s and it makes about 1.23 megawatts: eight times as much, because faster wind brings more air each second and each bit of air carries more energy.
Explore next
- Watch What If? Lab What if we could see the wind? Wind is moving air, and air is invisible. So people watch what the wind moves: smoke, leaves, flags, clouds and kites. Scientists even make wind maps from satellite pictures. Imagine the wind suddenly becoming visible, and follow the swirls, maps and kites that might appear.
- Watch What If? Lab What if lightning never struck? Lightning is a giant electric spark from a storm cloud. It's powerful, but it also does useful jobs: it turns some nitrogen in the air into plant food, and its fires help some forests renew. Imagine a world where lightning never struck, and see what would change and what would carry on.
- Watch What If? Lab What if earthquakes could be predicted? No scientist has ever predicted a major earthquake, and USGS says nobody knows how. What scientists can do is work out the chances of a quake in an area, send a warning seconds after one starts, and help design buildings that shake less. Imagine we could know the exact day, and follow what might change.
- Watch What If? Lab What if waves had no wind? Most ocean waves are made by wind blowing over the water. So what if the wind stopped everywhere? New waves would stop forming, but swells from earlier storms could keep rolling in for a while. And the tide would still come in and go out, because tides are made by the pull of the Moon and the Sun, not by wind.
- Watch Try it What If? Lab What if the wind blew twice as hard? A wind turbine turns moving air into electricity. In our model, a gentle 5 m/s wind lets a big turbine make about 0.15 megawatts. Double the wind to 10 m/s and it makes about 1.23 megawatts: eight times as much, because faster wind brings more air each second and each bit of air carries more energy.
- Watch Try it What If? Lab What if Earth had no atmosphere? Earth's air works like a jacket: it keeps heat in and carries it around. Take the air away in our model of a sandy patch of ground on the equator, and the coldest part of the night drops from about 13 °C to about 2 °C.
- Watch Try it What If? Lab What if there were no greenhouse gases? Greenhouse gases such as carbon dioxide and water vapor hold some of Earth's heat in, like a blanket. Take them all away in our energy-balance model and Earth's average temperature falls from about 15 °C to about −19 °C, well below freezing.
- Watch Try it What If? Lab What if there were more greenhouse gases? Adding greenhouse gases makes it harder for Earth's heat to escape, so the planet warms until it balances again. In our model a small change in how freely heat escapes warms Earth by about 2.6 °C, and the oceans make the warming take years.
For parents & teachers
What children will learn
- Wind is air moving from high to low pressure, caused by the Sun heating Earth unevenly.
- Wind carries heat, moisture and weather systems around the world, and helps wet things dry.
- Some plants rely on wind to carry their seeds, and sailors have long relied on the trade winds.
- Thought experiments separate known facts from reasoned ideas.
Recommended ages: 5 to 17 · About 15 minutes
Talk about it
- Where have you seen or felt the wind today? What was it moving?
- Why might a farmer, a sailor and a pilot each care about the wind?
- Why is it important to say that some of these outcomes are only ideas?
Try at home or in class
- Build a paper-hoop "seed" flyer from a straw, two paper strips and tape (Columbus State University's Seeds on the Move activity). Toss it across the room once with a desk fan on low behind it and once with the fan off, and compare how far it goes. A grown-up sets up the fan.
- Hang two equally damp cloths indoors, one in the breeze of a desk fan and one away from it, and check which dries first: NOAA notes that wind helps wet things dry.
Key vocabulary: wind, air pressure, evaporation, jet stream, trade winds, doldrums
Where these facts come from
- Why Does Wind Blow? , NOAA NESDIS
- Global atmospheric circulations (JetStream) , NOAA National Weather Service
- What Is the Jet Stream? , NOAA NESDIS
- Weather systems and patterns , NOAA Education
- What Makes It Rain? , NOAA NESDIS
- Air Quality , NOAA Physical Sciences Laboratory
- What are the trade winds? , NOAA National Ocean Service
- What are the doldrums? , NOAA National Ocean Service
- Oxbow At Home: Seeds on the Move , Columbus State University, Oxbow Meadows Environmental Learning Center
- Up, up and away: Dandelions use upward winds to spread seeds , Cornell Chronicle, Cornell University
Checked, not yet human-reviewed. Last updated October 24, 2026. Spotted a mistake? Tell us.