Air

Sky on fire, quietly

What Are the Northern Lights?

Particles from the Sun crash into high air and make it glow like a neon sign.

Let’s go →

Three centuries of weather

Jupiter's Storm That Never Stops

Jupiter's Great Red Spot is a storm bigger than Earth that never blows out.

Let’s go →

Nothing to carry the sound

Why Is Space Silent?

Space is silent because sound is a wave in a material, and there is essentially no material out there.

Let’s go →

The Sun is leaking

What Is the Solar Wind?

The solar wind is a steady stream of particles blowing out from the Sun.

Let’s go →

Both, and neither

Is Space Hot or Freezing?

Space is not really hot or cold, because temperature needs particles and space has almost none.

Let’s go →

The air is doing it

Why Do Stars Twinkle but Planets Do Not?

Twinkling happens in our atmosphere, not in the star, and planets are too broad for it to show.

Let’s go →

A night-sky flicker

Why Stars Twinkle

Moving air bends starlight on its way down, so the star seems to flicker.

Let’s go →

A blanket that will not lift

Why Is Venus Hotter Than Mercury?

Venus beats Mercury for heat because its thick atmosphere traps warmth that Mercury simply radiates away.

Let’s go →

An invisible ocean

Air Is Pressing on You

Air has weight, and the whole atmosphere presses down on everything.

Let’s go →

How big the push is

What Makes a Sound Loud?

Loudness comes from how big the air's squeeze is, not how fast it repeats.

Let’s go →

Air shoved out of the way

How Does a Parachute Slow You Down?

A parachute slows a fall by making you shove far more air aside, and that air pushes back hard.

Let’s go →

Force, spread out

What Is Pressure?

Pressure is force divided by area — a small area concentrates the same push.

Let’s go →

Air, pushed

How Does Sound Travel?

Sound travels as a squeeze passed from air molecule to air molecule.

Let’s go →

Squeeze and stretch

What Does a Sound Wave Look Like?

A sound wave is alternating bands of squeezed and spread-out air travelling along.

Let’s go →

Empty space cannot push

What Does Nothing Actually Do?

A vacuum does nothing at all; the interesting effects all come from the pressure of whatever surrounds it.

Let’s go →

Mostly air, held in a shape

Why Is Foam So Light?

Foam is mostly trapped air, which is why it is so light and such a good insulator.

Let’s go →

A lined pit that runs out of air

Where Does Rubbish Actually Go?

A landfill is a sealed lined pit where rubbish rots extremely slowly, because almost no oxygen reaches it.

Let’s go →

The bits that did not get to burn

Why Does a Fire Make Smoke?

Smoke is fuel that never finished burning — tiny solid specks, lifted away by the rising hot air.

Let’s go →

It thins rather than ends

Where Does the Air Stop?

The atmosphere has no boundary — air just gets thinner with height until it fades into space.

Let’s go →

Weighing the sky

How Does a Barometer Work?

A barometer measures the weight of air overhead, which falls before storms and rises before fine weather.

Let’s go →

Light getting bounced

Why Is the Sky Blue?

Air scatters blue light sideways, so it reaches your eyes from everywhere.

Let’s go →

Reading the sky

Why Do Clouds Have Different Shapes?

Puffy, flat or wispy — a cloud's shape shows how the air under it is moving.

Let’s go →

Droplets too small to fall

How Does Something That Heavy Float?

Clouds float because they are made of droplets so small that air resistance nearly cancels their fall.

Let’s go →

Where the rain never arrives

Why Are Deserts Dry?

Deserts are dry because sinking air, mountains or distance keep the rain away.

Let’s go →

Escaping one at a time

Where Does a Puddle Go?

Puddles vanish because fast-moving surface molecules escape into the air as vapour.

Let’s go →

A cloud on the ground

What Is Fog?

Fog is simply a cloud that has formed at ground level.

Let’s go →

A blanket that lets light in

How Does the Air Keep Earth Warm?

Greenhouse gases let sunlight in but trap the heat radiating back out, keeping Earth far warmer than it would be.

Let’s go →

Air that will not leave

What Makes a Heatwave?

A heatwave happens when sinking, stuck air blocks clouds and lets heat build day after day.

Let’s go →

A heat engine over warm water

How Do Hurricanes Form?

Hurricanes are giant spinning storms powered by heat released from warm ocean water.

Let’s go →

A fast band steering the weather

What Is the River of Wind Up High?

Jet streams are ribbons of fast high wind formed where warm and cold air meet, and they steer our weather.

Let’s go →

A sea breeze the size of a continent

What Is a Monsoon?

A monsoon is a continent-sized sea breeze that reverses with the seasons.

Let’s go →

The sky letting go

Where Does Rain Come From?

Rain falls when tiny cloud droplets merge until they are too heavy to float.

Let’s go →

An old rhyme, half right

Does a Red Sky Really Predict the Weather?

A red sunset means clear dry air to the west, which in Britain is tomorrow's weather.

Let’s go →

Land and sea disagree

Why Is It Windy at the Beach?

Land warms faster than water, so air rises over the land and pulls a breeze in from the sea.

Let’s go →

Plants moving without moving

How Do Seeds Travel?

Seeds travel by wind, water, animals or launching, because plants cannot move.

Let’s go →

Light taking the long way

Why Are Sunsets Orange?

At sunset light travels through much more air, which strips out the blue.

Let’s go →

Air exploding

Why Does Thunder Rumble?

Thunder is the sound of air exploding away from a lightning bolt.

Let’s go →

A spin tipped upright

How Does a Tornado Form?

A tornado is a horizontal rolling column of air tipped upright and stretched by a storm.

Let’s go →

Physics run forward

How Can Anyone Predict Tomorrow?

A forecast measures today's air everywhere and calculates it forward using known physics.

Let’s go →

Air evening things out

What Makes Wind Blow?

Wind is air flowing from high pressure to low pressure because the Sun heats unevenly.

Let’s go →

Named for where it starts

Where Does the Wind Come From?

Wind is named for the direction it comes from, which tells you what kind of air is arriving.

Let’s go →

A defence aimed at nothing

Why Does Pollen Make Some People Sneeze?

An allergy is your immune system mounting a real defence against something harmless, and the symptoms are the defence, not the pollen.

Let’s go →

Fetching oxygen, dumping waste

Why Do We Breathe?

We breathe to collect oxygen for burning food and to get rid of carbon dioxide.

Let’s go →

Air that took a wrong turn

Where Does a Burp Come From?

A burp is swallowed air coming back up — gas rises through liquid and the top of your stomach is the only way out.

Let’s go →

A sudden gale, from inside

Why Do You Cough?

A cough seals your airway, builds pressure behind it, and releases it as a blast fast enough to sweep the tube clear.

Let’s go →

Demand outrunning supply

Why Does Exercise Make You Puff?

You puff during exercise because muscles need far more oxygen than at rest.

Let’s go →

Vibration turned into signals

How Do You Hear?

Hearing converts air vibrations into nerve signals through the eardrum and hair cells.

Let’s go →

Half a tennis court, folded up

Why Are Lungs Spongy Instead of Hollow?

Lungs are spongy because oxygen can only cross where air touches blood, and folding gives an enormous amount of touching.

Let’s go →

Catching actual molecules

How Does Smelling Work?

You smell things because their molecules float into your nose and lock onto receptors.

Let’s go →

Blasting the nose clear

Why Do We Sneeze?

A sneeze is an automatic blast of air that clears irritants from your nose.

Let’s go →

Some of it — and the sea makes more

Do Trees Make the Air We Breathe?

Trees make oxygen, but tiny ocean plankton produce about half of it.

Let’s go →

Two flaps, flapping very fast

How Do You Make Your Voice?

Air from your lungs makes two flaps in your throat vibrate, and your mouth shapes that buzz into speech.

Let’s go →

Everything about it is built for lightness

How Does a Bird Stay Up?

A bird flies on curved wings that bend passing air downwards, carried by hollow bones and enormous chest muscles.

Let’s go →

One structure, many jobs

Why Do Birds Have Feathers?

Feathers are branching structures that zip into light, stiff sheets for flight, warmth and display.

Let’s go →

Taking oxygen out of water

How Do Fish Breathe Underwater?

Fish use gills to pull dissolved oxygen out of the water flowing past.

Let’s go →

Fruit rusting

Why Does a Cut Apple Turn Brown?

A cut apple browns because a released enzyme reacts with oxygen to build brown pigment.

Let’s go →

A gas being made

Why Does Baking Soda Fizz?

Baking soda fizzes because it reacts with acid to make carbon dioxide gas.

Let’s go →

Air pushing back

Why Does a Balloon Stay Blown Up?

A balloon stays inflated because air molecules inside push outward against the stretched rubber.

Let’s go →

A fungus breathing out

Why Does Bread Rise?

Bread rises because living yeast produces gas bubbles trapped inside the dough.

Let’s go →

The laziest possible shape

Why Are Bubbles Always Round?

Bubbles are round because a sphere uses the least surface to hold the air inside.

Let’s go →

Faster sound, same vibration

Why Does Helium Make Your Voice Squeaky?

Helium makes sound travel faster, shifting your throat's resonances up into a squeak.

Let’s go →

A muscle misfiring

What Causes Hiccups?

A hiccup is the diaphragm spasming while the vocal cords snap shut.

Let’s go →

Trading height for distance

Why Does a Paper Plane Glide?

A paper plane glides by falling forward slowly while air pushes up on its wings.

Let’s go →

Air losing its grip on water

Why Do Windows Fog Up?

Windows fog when warm moist air touches cold glass and its water condenses.

Let’s go →

Iron combining with oxygen

Why Does Metal Go Rusty?

Rust forms when iron reacts with oxygen and water to make a flaky new substance.

Let’s go →

Gas hiding in plain sight

Where Do the Bubbles in Fizzy Drinks Come From?

Fizzy drinks hold dissolved gas under pressure, and opening the bottle lets it bubble out.

Let’s go →

Air pressure pushing from outside

How Does a Straw Work?

A straw works because removing air lets outside air pressure push the drink up.

Let’s go →

Proteins forced to unfold

How Does Egg White Turn Into Foam?

Whisking unfolds egg white proteins so they wrap around air bubbles and hold them.

Let’s go →

Angled blades catching moving air

How Does a Windmill Turn?

Windmills turn because angled blades deflect moving air and the air pushes back.

Let’s go →

Cooling and catching

Why Do We Yawn?

Yawning appears to cool the brain, and it spreads contagiously between people.

Let’s go →

Throwing air downwards

Why Does a Wing Hold a Plane Up?

A wing holds a plane up by deflecting air downward; the air pushes back, and that push is lift.

Let’s go →

Carrying heat out, not cold in

How Does a Box Make Itself Cold?

A fridge does not make cold: it carries heat out of the box using a gas that is squeezed hot and expanded cold.

Let’s go →

A fan and a hot wire, in that order

What Is Inside a Hairdryer?

A hairdryer is a fan and a coil of thin wire — and hair dries because moving air carries water away, not because the air is hot.

Let’s go →

Stopping the cabin spinning

Why Does the Little Tail Rotor Matter?

A helicopter needs a tail rotor because turning the main blades twists the body the opposite way.

Let’s go →

The same bag, holding less

Why Does Hot Air Lift a Balloon?

A hot-air balloon rises because heating the air drives some of it out, leaving the balloon lighter than the air around it.

Let’s go →

Two pushes and a leftover

How Does a Boat Sail Into the Wind?

A sailboat goes upwind because the sail pushes sideways, the keel blocks sideways, and the leftover is forward.

Let’s go →

The room does the pushing

Why Does Suction Pick Things Up?

Nothing sucks: a vacuum cleaner lowers the pressure inside, and the room's own air pushes dust in.

Let’s go →

Pushed from below, never pulled

How Does Water Get Up to the Top Floor?

Water reaches an upstairs tap because a pump pushes it from below — sucking it up stops working after about ten metres.

Let’s go →

Three blades, and each one is a wing

How Does a Wind Turbine Work?

A wind turbine's blades are wings: moving air lifts them sideways, spinning a shaft that turns a generator.

Let’s go →