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Food & kitchen

Cooking, baking, and what happens on the plate — 53 tiny stories from every shelf.

Jostling passed along

Why Does a Metal Spoon Get Hot?

A metal spoon heats up because vibrating atoms pass their jostling along, and metals pass it exceptionally well.

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Sour, and eager to give something away

What Makes Something an Acid?

An acid is a substance that hands out a tiny particle, which is what makes it sour and able to eat into things.

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Where roast smells come from

Why Does Food Turn Brown When It Cooks?

Above about 140 °C, sugars and proteins react to make brown colour and roasted flavour.

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Shaking a mixture until it gives up

How Does Cream Turn Into Butter?

Churning cream smashes the coats off fat droplets so they clump into butter.

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Splitting a liquid into two

How Does Milk Become Cheese?

Cheese is milk split into curds and whey, with the curds pressed, salted and left to age.

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A narrow window of heat

Why Does Custard Suddenly Scramble?

Egg proteins unfold and thicken custard, but a little more heat makes them clump.

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Oil goes far hotter than water

Why Does Frying Taste Different From Boiling?

Oil reaches far higher temperatures than water, so frying browns food that boiling only softens.

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A mesh built from fruit

Why Does Jam Set?

Jam sets when pectin from fruit forms a mesh that traps the sugary liquid.

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Mostly a surface job

What Does a Marinade Actually Do?

Marinades flavour and tenderise the surface of food — they hardly penetrate at all.

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Making the jar uninhabitable

Why Does Pickling Stop Food Rotting?

Pickling makes food too acidic and too salty for the microbes that would spoil it.

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A rock you are allowed to eat

Where Does Salt Come From?

Salt is a mineral that comes from evaporated seawater or from underground beds left by ancient seas.

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The same temperature, treated gently

Why Do Cooks Simmer Instead of Boil?

Boiling and simmering are the same temperature; boiling only adds violence.

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Cooking without soaking

Why Does Steaming Keep the Flavour In?

Steam cooks food at boiling temperature without dissolving its flavour away into water.

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Turning tough into silky

Why Do Cooks Boil Bones for Hours?

Hours of gentle heat turn tough collagen into gelatine, giving stock its body.

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A shape that fits a lock

Why Is Sugar Sweet?

Sugar is a molecule from plants that fits the sweet receptors on your tongue — and it feeds almost everything alive.

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Bacteria doing the thickening

How Does Milk Become Yoghurt?

Bacteria turn milk sugar into acid, which makes milk proteins clump into a soft set.

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Not everything scales

How Do You Double a Recipe?

Doubling a recipe doubles the ingredients but not the pan, the time, or the temperature.

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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.

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Living things too small to see

What Are Germs?

Germs are microscopic organisms that multiply in your body and cause illness.

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An empty tube, squeezing anyway

Why Does Your Stomach Rumble?

A rumble is your empty stomach and gut sweeping themselves clean, and hunger is a hormone clock, not an empty feeling.

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Seven metres of grabbing

Why Are Your Intestines So Long?

Your intestines are long because food is only absorbed at the wall, and length, folds and fuzz all buy more wall.

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The chemistry room

What Is a Liver For?

The liver is where everything you absorb goes first — to be stored, rebuilt into something useful, or made safe.

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The tip of something bigger

What Is a Mushroom?

A mushroom is the spore-making fruit of a much larger underground fungus network.

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A plant and its lunch

What Is Inside a Seed?

A seed contains a tiny plant and a food store to launch it.

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Catching actual molecules

How Does Smelling Work?

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

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Taken apart, then absorbed

What Happens to Food You Eat?

Digestion breaks food into molecules small enough to enter your bloodstream.

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Five basics, plus your nose

How Does Taste Work?

The tongue detects five basic tastes; the rest of flavour is smell.

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A toolkit in your mouth

Why Do Teeth Have Different Shapes?

Teeth have different shapes because cutting, tearing and grinding need different tools.

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Chemical trails

How Do Ants Find Food?

Ants find food by laying scent trails that automatically favour the shortest path.

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A deal, not a favour

Why Do Bees Visit Flowers?

Bees visit flowers for food, and carry pollen between them as payment.

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Thousands of hiding places

How Does a Squirrel Find Its Buried Nuts?

A squirrel remembers roughly where it buried each nut, then finds the exact spot by smell — and the ones it forgets become trees.

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Fruit rusting

Why Does a Cut Apple Turn Brown?

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

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A gas being made

Why Does Baking Soda Fizz?

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

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Water turning to gas inside itself

What Are the Bubbles When Water Boils?

Boiling bubbles are water vapour forming inside the liquid, not trapped air.

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A wire crossed

Why Does Ice Cream Give You a Headache?

Brain freeze is a cold reflex in the roof of your mouth that your brain reports as head pain.

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A fungus breathing out

Why Does Bread Rise?

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

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Kind to the blade, unkind to germs

Why Are Chopping Boards Made of Wood?

Wood is soft enough to protect a knife edge and dries out in a way that kills bacteria.

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A grain that drinks

Why Does Rice Need Exactly the Right Water?

Rice grains swell by absorbing a set amount of water, so the measure matters more than the time.

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Broken up, not vanished

Where Does Sugar Go in Water?

Dissolving breaks a solid into single molecules spread evenly through the liquid.

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Ice leaving without melting

What Is Freezer Burn?

Freezer burn is ice escaping food as vapour without ever melting, leaving it dry.

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Smell molecules escaping

Why Does a Fridge Smell of Everything at Once?

Foods release smell molecules that build up in a sealed fridge and settle on everything.

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Heat always moving in

Why Does Ice Cream Melt?

Ice cream melts because heat always flows from the warmer room into it.

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A fungus, eating your lunch

What Is the Fluff on Old Bread?

Mould is a fungus digesting the bread and raising stalks that release spores into the air.

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A chemical booby trap

Why Does Chopping Onions Make You Cry?

Cutting an onion mixes two chemicals into a stinging gas, and your eyes flood to rinse it away.

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Cloudy water is useful water

Why Do Cooks Save the Pasta Water?

Pasta water carries starch, which thickens a sauce and helps it stick to the pasta.

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Steam bursting out

Why Does Popcorn Pop?

Popcorn pops when trapped water turns to steam and bursts the hard shell.

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Stopping the heat walking out

Why Does a Lid Make Water Boil Faster?

A lid stops steam carrying heat away, so the pan reaches boiling much faster.

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Making water boil hotter

How Does a Pressure Cooker Cook Faster?

A sealed pot raises the pressure inside, so water boils hotter and food cooks faster.

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All the force in one line

Why Is a Sharp Knife Safer Than a Blunt One?

A sharp knife needs less force because all the push lands on a very thin edge.

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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.

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Metal and protein shaking hands

Why Does Food Stick to the Pan?

Proteins bond to hot metal and release only once a crust has formed underneath.

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Sugars and proteins reacting

Why Does Toast Go Brown?

Toast browns because heat makes sugars and proteins react into new flavour compounds.

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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.

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