69 questions · 34 almanac · 1 findings

Everyday and Recreational Physics

Physics found in ordinary phenomena, from coffee sloshing to banana peels.

Almanac The Physics of Not Losing Your Biscuit
  • How did Len Fisher model biscuit dunking as a problem in capillary action and porous media?
  • What balance of forces decides when a dunked biscuit collapses rather than holding together?
Almanac A Danger Nobody Was Willing to Name
  • What did the study 'The Collapse of Toilets in Glasgow' actually document?
  • What typically caused the ceramic lavatories in the study to fail?
  • Why does the entry argue this kind of undignified hazard gets overlooked by safety literature?
Almanac The Case for Coconut Helmets
  • Why can a falling coconut cause a serious head injury given the tree's typical height and fruit weight?
Almanac A Vortex Inside the Shower
  • Why does a shower curtain billow inward and cling to a bather when hot water runs?
  • How does Bernoulli's principle explain the low-pressure vortex created by a shower spray?
  • What method did David Schmidt use to model and confirm the shower curtain vortex?
Almanac Whatever Can Go Wrong, Will
  • What incident during the 1949 Air Force rocket-sled experiments led to the coining of Murphy's Law?
  • Who were the three men credited with the origin of Murphy's Law, and what was each one's role?
  • How did Murphy's Law spread from a press conference remark into common language?
Almanac Five Seconds Is Not Enough
  • How did Jillian Clarke test the validity of the Five-Second Rule?
  • How quickly did food dropped on contaminated tiles pick up E. coli in her experiment?
  • What differences did Clarke find between men and women in invoking the Five-Second Rule?
Almanac A Drop Nobody Ever Saw Fall
  • Why does pitch behave like a solid when struck but flow like a liquid over long timescales?
  • How long did Thomas Parnell wait before even opening the sealed funnel of pitch?
  • Why did no one, including the dedicated webcam, ever manage to witness a drop actually falling?
Almanac Syrup Swims No Slower Than Water
  • Why did swimmers move at the same speed in the thickened water as in normal water?
  • What longstanding debate in fluid dynamics did this experiment settle?
Almanac A Built-In Seatbelt for a Woodpecker's Brain
  • How many times a day does a woodpecker strike a tree, and at what deceleration force?
  • What anatomical features protect a woodpecker's brain from repeated high-speed impacts?
Almanac The Arithmetic of Nobody Blinking
  • What rule of thumb did Svenson and Barnes devise for how many photos to take of a group?
  • How does lighting condition change the number of exposures needed to avoid a blinking subject?
  • What blink statistics did the researchers use to build their formula?
Almanac Why Spaghetti Never Snaps Clean
  • Why does dry spaghetti almost always break into more than two pieces?
  • What earlier physicist tried and failed to solve the spaghetti-breaking problem?
Almanac What a Beard Holds Onto After Washing
  • How did 1960s Army researchers test whether beards harbour dangerous microbes?
  • Did washing fully remove bacteria and viruses from contaminated beards?
Almanac The Ponytail Shape Equation
  • What physical factors does the Ponytail Shape Equation combine to predict the shape of a swaying ponytail?
Almanac Running on Water, Given Lunar Gravity
  • Why is it physically impossible for a human to run across water on Earth?
  • How does the Moon's lower gravity change the biomechanics of running enough to make water-running theoretically possible?
  • Why did the researchers rely on modelling rather than an actual experiment on the Moon?
Almanac The Onion's Dedicated Weeping Department
  • What compound does a cut onion release that causes eyes to water, and how does it form sulphuric acid in the eye?
  • Why had the enzyme behind onion tears gone unnoticed for decades despite the tear-inducing compound being known?
Almanac The Banana Peel, Finally Measured
  • What substance does a banana peel release under pressure that makes it so slippery?
  • How did the researchers compare the slipperiness of banana peel against orange and apple peel?
  • How does the friction coefficient of a banana peel compare to wet ice or a waxed floor?
Almanac Is a Cat a Liquid?
  • What is the Deborah number, and how does it distinguish a liquid from a solid?
  • Why does a cat poured into a vase count as exhibiting fluid behavior under this measure?
  • What makes Fardin's cat-fluidity paper a genuine application of rheology rather than just a joke?
Almanac A Beard Is a Shock Absorber
  • How did Beseris and colleagues test whether facial hair cushions blows to the jaw?
  • What did the synthetic bone experiments show about hairy versus bare samples?
  • What evolutionary explanation does the beard-as-armor hypothesis suggest for human facial hair?
Almanac Nobody Collides in a Crowded Corridor
  • How did the Eindhoven team collect millions of pedestrian trajectories to study crowd behavior?
  • What forces of mutual avoidance did the statistical analysis extract from ordinary foot traffic?
  • Why do near-misses in a crowd reflect an orderly process rather than chaos?
Almanac One Distracted Walker Trips Up the Crowd
  • How did Murakami's team test the effect of phone distraction on pedestrian flow?
  • Why does a single distracted walker degrade traffic flow for everyone nearby, not just themselves?
Almanac Ducklings Surf Their Mother's Wake
  • How does a mother duck's bow wave generate lift for the ducklings swimming behind her?
  • Why does each duckling further back in the line expend less effort than the one in front?
Almanac Hair Whorls Ignore the Equator
  • What is the popular misconception about hair whorls and the Coriolis force that this study tested?
  • What did the study find about the direction hair whorls spiral in the northern versus southern hemisphere?
Almanac The Physics of a Sauce That Breaks
  • What causes a cacio e pepe emulsion to break into a grainy, clumped sauce?
  • What role does starch from pasta-cooking water play in stabilising the cheese-and-water emulsion?
  • What threshold temperatures and starch concentrations did the physicists identify for a stable sauce?