Deep Dives
Long-form explanatory essays that take one idea, question or story and pursue it properly.
8 pieces so far- How a Rock Ended Up Running Your Phone Nearly every phone, laptop and satellite begins as a lump of quartz. Getting from one to the other is one of the strangest supply chains in the world. The scienceSilicon for chips is made by stripping oxygen from quartz with carbon, turning the silicon into a gas that can be distilled clean, then growing a single perfect crystal from the melt; it must be so pure because a few stray atoms in a billion change how it conducts electricity.
- Your Fridge Is Secretly Heating Your Kitchen Heat naturally flows from hot to cold. Your fridge spends all day forcing it the other way. Here's how. The scienceA fridge pumps heat from its cold inside to the warmer room, which heat never does by itself: a refrigerant boils at low pressure inside the fridge, absorbing heat, and is then compressed so that it is hotter than the room and can give that heat away, with the compressor's work paying for the uphill trip.
- Your Phone Finds You Using Clocks in Space The blue dot on your map depends on atomic clocks, the speed of light, a fourth satellite you didn't know you needed, and a correction from Einstein. The scienceA satellite navigation receiver works out its distance from several satellites by timing how long their signals take to arrive at the speed of light; four satellites fix its position and correct its own clock, and the satellites' atomic clocks must be adjusted for the effects of relativity.
- The Sky Is Blue Because Air Is Picky The same tiny effect explains the blue of noon and the orange of evening, and why the sky on Mars does the opposite. The scienceAir molecules, much smaller than the wavelength of light, scatter it in proportion to one over the wavelength to the fourth power, so blue light is scattered around five times more than red; that makes the daytime sky blue and leaves mostly red and orange light in a low sun's long path through the air.
- Why the Monsoon Almost Always Turns Up in June A season's worth of weather arrives within a week or so of the same date every year. Here's the engine behind it, and why it partly runs on its own rain. The scienceThe monsoon is a seasonal wind reversal driven by land heating faster than the sea: in summer, hot air rising over the Indian subcontinent and Tibetan Plateau draws moist air in from the ocean, and the heat released as that moisture condenses into rain strengthens the circulation further.
- Charging Your Phone Means Pushing Lithium Uphill Plug in your phone and nothing seems to happen. Inside, billions of billions of lithium ions are being forced to move house, from a comfortable home to a cramped one, and that is where the energy is stored. The scienceIn a lithium-ion battery, charging uses electrical energy to push lithium ions out of a metal oxide and in between the layers of graphite, a higher-energy arrangement; when you use the phone, the ions flow back and the electrons they leave behind travel through the phone's circuits as current.
- A Vaccine Is a Wanted Poster for a Germ Your immune system is a brilliant detective that starts every case days behind. A vaccine hands it the description in advance, and it never forgets a face. The scienceYour adaptive immune system holds billions of different B and T cells, each able to recognise one particular shape; a vaccine shows it a harmless version of a germ's shapes, so the matching cells multiply and leave long-lived memory cells that can respond within days, instead of weeks, when the real germ arrives.
- Bread Is Held Up by Billions of Tiny Fungi Every loaf is a sponge full of gas made by living things. The holes are where the gas was, and the walls between them are made of a protein net you built with your hands. The scienceEnzymes in flour break starch into sugars that yeast ferments into carbon dioxide and alcohol; kneading links two wheat proteins into an elastic gluten network that traps the gas, and in the oven the gas expands, the starch and proteins set, and the crust browns through the Maillard reaction.