The Atomleys are the sort of family who make science teachers smile and insurance companies groan.

Every Saturday morning, Mr Atomley claps his hands and declares: “Science in the Kitchen!” Whether or not the kitchen has recovered from last Saturday is irrelevant. Mrs Atomley fetches the mop with the air of someone who trusts bleach more than miracles. Galaxa (10) and Rocket (7½-the half is non-negotiable) sprint for their goggles. The cat does not sprint. The cat lurks in the bread bin and watches, which is its version of filing a complaint.

Today’s experiment is pudding. Simple, harmless pudding. Eggs, milk, sugar, flour, vanilla. Nothing explosive. (If you just felt the story wink, well spotted.) “Team briefing,” says Mr Atomley, tapping the whiteboard. He has drawn three jars labelled Solid, Liquid, Gas, each full of dots.

“States of matter!” he announces like a magician revealing rabbits.

“Flour is a solid,” says Galaxa, poking the bag. “Particles close together. Holds shape.”

“Milk is a liquid,” adds Mrs Atomley, pouring from jug to jug. “Flows, takes the shape of its container.”

Rocket waves his arms. “Gas!” Then he falls into a chair. “Correct!” says Mr Atomley, drawing arrows as he makes notes:

Solids: particles close, vibrating in place.

Liquids: close but sliding.

Gases: far apart, moving fast, filling space.

“Like Uncle Bert when there’s trifle,” says Galaxa.

“Oi!” says Uncle Bert, appearing in the doorway with a spoon. He has an uncanny ability to arrive whenever dessert is mentioned.

Eggs crack, sugar sprinkles, vanilla drifts. Galaxa whisks until the mixture turns pale and glossy. Rocket leans in too far and gives himself a moustache of batter. “Lovely,” says Mrs Atomley. “We’ll steam it gently.”

Or they would have, except Mr Atomley has an idea.

From his pocket, he produces a brown bottle. The label reads: Do Not Shake!

“What’s in it?” Galaxa asks suspiciously.

“A fermentation starter,” says Mr Atomley proudly. “Yeast, sugar, optimism. It produces gas.”

“Gases spread out and try to escape,” says Rocket, eager to show off.

“Exactly,” beams Mr Atomley. “Tiny bubbles to lift the batter. Like a hot-air balloon for pudding!”

“Micro-test,” says Mrs Atomley firmly, remembering the Soup Disaster. (You don’t want to know)

“Micro-test,” agrees Galaxa.

Mr Atomley loosens the cap. The bottle sighs like a grumpy dragon. One drop plops into the mixture.

The pudding blorps. Never trust food that blorps. (You’ll thank me later)

The bowl slides into the oven. The family crowds the door. The cat crouches near the toaster, tail twitching. Inside, the pudding swells, golden and proud. Steam fogs the oven glass. Droplets appear and race down the pane.

“Condensation,” says Mrs Atomley. “Water vapour cools on the glass, changes back to liquid.”

Rocket leaves a nose print on the glass. Galaxa elbows him aside to add her own.

“Remember,” says Mr Atomley, “heating gas makes particles spread out. Expansion increases pressure.”

“Which means,” Galaxa says, watching the trembling dome, “our pudding is full of pushy bubbles.”

The timer pings.

“Stand back,” warns Mrs Atomley.

She opens the oven.

For one glorious second the pudding sits high as a golden moon. Then it burps.

Bang!

A custard wave slaps across the kitchen. Raisins ping the ceiling like hailstones. Steam whooshes so strongly the curtains flap like startled pigeons.

The sound is part pop, part cannon, part rude hiccup. The smell, sweet, eggy, faintly scorched, settles over everything. The cat springs straight up, lands on the toaster, and glows faintly green. (We’ll come back to that.)

“Science!” cries Mr Atomley, thrilled.

“Floor,” groans Mrs Atomley, watching pudding spread like lava.

Rocket pokes the lake with a spoon. It sinks without a trace. “This is brilliant.”

Galaxa points at the window. “Condensation again! Gas back to liquid! All states involved!”

“And me?” asks Uncle Bert faintly, as something curious begins to happen to him.

Because now the bubbles arrive.

Huge pudding-gas bubbles roll lazily from the oven, wobbling like jellyfish. They bump the ceiling and cluster together.

Uncle Bert, standing exactly where he shouldn’t, is scooped up by the seat of his trousers.

He rises slowly, legs dangling. “Oh,” he says. “Hello ceiling.”

“Grab him!” Galaxa yells, climbing onto a chair.

Rocket slides the ladder across the custard like-slick floor and clutches his uncle’s sock. Galaxa grabs his sleeve.

“Don’t pop the bubble above him!” warns Mrs Atomley.

“Hot gases are less dense than cooler air,” Mr Atomley explains (because explaining is his reflex). “That’s why the bubble is buoyant, pushing up harder than gravity pulls down.”

Rocket grunts, slipping on custard. “Uncle, could you stop wriggling?”

“I’m not wriggling, I’m drifting,” Uncle Bert replies indignantly, rotating into the lampshade.

“Translation,” pants Rocket, “Uncle Bert is a balloon.” “An elegant balloon,” Bert insists, attempting a wave.

Rocket claps two sieves around a spare bubble. POP! Sweet mist sprays out. Uncle Bert drops an inch. Galaxa and Rocket haul him down until his shoes squelch onto the tiles.

“I saw my life flash before my eyes,” he says gravely. “Mostly sandwiches.”

The kitchen looks like a dessert has sneezed. Pudding clings to cupboards. Steam blurs the air. A heroic raisin slides down a cupboard door like a mountaineer descending.

The smell is everywhere. vanilla custard mixed with hot metal and faint singe. Even the mop looks daunted.

“All right,” says Mrs Atomley. “Mops. Towels. Now.”

They mop and dab. The sponge honks like a shy trumpet. Rocket herds raisins into the dustpan. Galaxa scrapes the oven tray. The cat pads through, glowing faintly, tail high with disapproval.

“Review,” says Mr Atomley, writing furiously:

Gas from yeast made the pudding rise.

Heat expanded the gas, building pressure.

No vents = pop.

Buoyancy: hot gas lifted Uncle Bert.

“Solid, liquid, gas,” recites Galaxa. “Particles close, sliding, far apart. Slow, slippy, speedy.”

“Scientific adjectives!” Rocket cheers.

“Next time,” says Mrs Atomley, “we measure, we vent, and we do not float relatives.”

From the garden comes Mr Jenkins’ voice: “Everything all right? Smells like ambitious custard!”

“Fine!” chorus the Atomleys.

“Educational,” adds Mr Atomley.

“Moist,” adds Uncle Bert, wringing out a sleeve.

At last, the oven exhales its last sigh. A modest survivor of pudding trembles in a tin, guilty but edible.

“Debrief,” says Mrs Atomley. She can debrief anything, even thunderstorms. (It’s the truth)

Mr Atomley taps the board:

Yeast made carbon dioxide.

Evaporation in oven. Condensation on windows.

Buoyancy lifted Uncle Bert.

Diffusion explains why the hall smells like custard.

“We’ll try again,” says Galaxa. “With proper leavening, bicarbonate of soda.”

“And lower heat,” says Rocket.

“And vent holes,” says Mrs Atomley. “Vents are friends.” Uncle Bert raises a hand. “Perhaps ropes?”

Mrs Atomley writes firmly:

Rule 7: No Hovering Uncles.

To finish on a win, they run three small demos.

Experiment A: Condensation. Mrs Atomley holds a cold tray above kettle steam. Droplets form and run. “Gas to liquid,” Galaxa observes, watching the trail of water zigzag.

Experiment B: Evaporation. A cloth over hot water cools where evaporation steals energy. “Liquid to gas needs energy,” Rocket explains. “So, the surface cools.” He presses the patch to his cheek and yelps: “Cold!”

Experiment C: Diffusion. Galaxa opens the vanilla bottle just a crack. Rocket, by the door, raises his hand when he smells it. “Particles moving from crowded to less crowded places,” Galaxa says. “That’s why the whole hallway smells sweet now.”

Mr Atomley beams. “Brilliant.” He underlines Solid • Liquid • Gas in pudding-coloured ink.

The neighbour hovers hopefully at the window. Mrs Atomley inspects a surviving wedge of pudding, declares it safe, and serves ceremonial spoonfuls. Even the cat accepts a raisin, with the face of royalty, tolerating a local festival.

Rocket scrawls a final note on the board:

Findings: Goggles are non-negotiable.

Pudding is slippery.

Deep in the oven, the last bubble whispers pop, a quiet full stop to the chaos.

And that, dear reader, is how the Atomleys turned a Saturday dessert into a masterclass on states of matter: solids holding shape, liquids flowing, gases escaping; evaporation rising, condensation returning; expansion pushing, buoyancy lifting; diffusion nosing in where it isn’t wanted.

Bring your goggles for next time. The Atomleys are planning to make ice behave, and ice, like uncles, doesn’t always follow instructions.