- How does the gas-filled tube in a Geiger counter turn a single alpha particle into a measurable electrical pulse?
- What problem were Geiger and Rutherford trying to solve when they built the original detector at Manchester?
- Why did the Geiger counter make it possible to observe radioactive decay as discrete quantum events rather than bulk averages?
Radar Technology
The development and use of radio detection and ranging.
- What did Victor Hess measure during his balloon ascent to nearly 5,000 metres that overturned the terrestrial-source theory?
- What methods did Theodore Richards use to push measurement error into the fourth and fifth decimal place?
- How did Harlow Shapley use Cepheid variable stars to measure distances to globular clusters?
- Why is the relationship between a Cepheid's pulsation period and its luminosity useful as a cosmic distance ruler?
- Why was a stable metrological standard so important to the International Bureau of Weights and Measures in the 1890s?
- How did Invar change the precision of pendulum clocks and surveying instruments?
- How do Cepheid variable stars let astronomers measure distances to other galaxies?
- How did Zsigmondy's ultramicroscope let him detect particles too small to be resolved directly?
- What technical advance in the 1920s finally made it possible to record a single nerve fibre instead of a smeared average?
- Why did Robert Watson-Watt convince the Air Ministry that a radio 'death ray' was implausible but radio detection was viable?
- How did the Chain Home stations use reflected radio waves to detect approaching aircraft?
- What limitations did the early Chain Home system have, and how did operators compensate for them?
- How did the early-warning minutes provided by Chain Home affect the outcome of the Battle of Britain?
- Which fields of science and technology were most accelerated by wartime pressure, and why?
- Why was Chain Home technically inferior to contemporary German radar despite being more effective in battle?
- How did Hugh Dowding's filter room and operations tables turn raw radar returns into usable warnings?
- How much warning time did Chain Home typically give Fighter Command before an incoming raid?
- What did German planners misjudge about the value of the Chain Home masts they knew existed?
- Why were Britain's wartime radar stations picking up mysterious interference in February 1942?
- Why was James Stanley Hey's discovery kept classified for four years before publication?
- How does the molecular beam method let physicists measure the magnetic properties of atoms directly?
- How did Erlanger and Gasser use oscilloscope technology to disprove the idea that a nerve acts like a single wire?
- What role did Geiger counters play in triggering the camera shutter?
- How did the Lovell Telescope end up being the only instrument able to track Sputnik's carrier rocket?
- Why do high frequencies peak near the base of the cochlea and low frequencies near the apex?
- What did Arecibo reveal about the true rotation period of Mercury?
- How precisely do QED's predictions match experimental measurement, and what does that precision actually mean in physical terms?
- What role did Churchill play in advancing radar and the British atomic bomb programme?
- Why did the quantum Hall effect become the new international standard for the ohm?
- How did splitting an atomic beam into two separated pulses make Ramsey's frequency measurements so much sharper?
- What flaw in Hubble's mirror caused its early images to be blurred, and how was it caused?
- What made Trinkaus's statistical approach to petty annoyances scientifically serious despite its subject matter?
- What differences did Clarke find between men and women in invoking the Five-Second Rule?
- Which frequency range turned out to be responsible for making fingernails-on-a-blackboard sound so unbearable?
- What two equipment errors were eventually found to explain the anomalous timing?
- Why is it difficult to measure whether the scheme actually reduced bribery?
- Why did respondents attributing personality traits to rocks reveal a flaw in the measurement scale?
- What triggered the 'resolution revolution' in cryo-EM after decades of finicky, indistinct images?
- Why are self-report measures of cognitive load considered problematic, and what alternative does item difficulty offer?