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Posts Tagged ‘Feynman

“At my age, the radiation will probably do me good”*…


The “banana equivalent dose” (BED) is a measure of radiation used to illustrate levels of emissions.  Bananas contain lots of potassium, which contains 0.01% potassium-40– which is radioactive.  The radiation exposure from eating a banana is deemed “1 BED,” roughly equivalent to 0.01 millirem (mrem).  (Happily, one would never be able to eat enough bananas to be dangerous, as our bodies excrete the potassium we’re consuming before it can do exposure damage.)

The existence of a clearly-understandable unit of this sort allows for easily-understood apples-to-apples (or, bananas-to-bananas) comparisons…

This is also roughly the exposure from having a single smoke detector.


Due to increased altitude; Mt Everest is more like 800 mrem (80,000 bananas) per year.


The granite in the walls is mildly radioactive. By comparison, the Vatican is about 800 mrem (80,000 bananas) per year.


More fruity comparisons at Mad Art Lab‘s “Yellow Alert

* Sir Norman Wisdom


As we peel, we might send thoughtful birthday greetings to Richard Philips Feynman; he was born on this date in 1918.  A theoretical physicist, Feynman was probably the most brilliant, influential, and iconoclastic figure in his field in the post-WW II era.

Richard Feynman was a once-in-a-generation intellectual. He had no shortage of brains. (In 1965, he won the Nobel Prize in Physics for his work on quantum electrodynamics.) He had charisma. (Witness this outtake [below] from his 1964 Cornell physics lectures [available in full here].) He knew how to make science and academic thought available, even entertaining, to a broader public. (We’ve highlighted two public TV programs hosted by Feynman here and here.) And he knew how to have fun. The clip above brings it all together.

– From Open Culture (where one can also find Feynman’s elegant and accessible 1.5 minute explanation of “The Key to Science.”)

email readers click here for video


Written by LW

May 11, 2015 at 1:01 am



In general we look for a new law by the following process. First we guess it. Then we compute the consequences of the guess to see what would be implied if this law that we guessed is right. Then we compare the result of the computation to nature, with experiment or experience, compare it directly with observation, to see if it works. If it disagrees with experiment it is wrong. In that simple statement is the key to science. It does not make any difference how beautiful your guess is. It does not make any difference how smart you are, who made the guess, or what his name is – if it disagrees with experiment it is wrong.

– Richard Feynman

Paul Dirac is famous for suggesting, “predicting,” in 1929, that there must be a positively-charge electron– or “positron.”  But until 1932, and Carl Anderson’s confirming cloud chamber experiments at Cal Tech, antimatter was just that– a suggestion, a prediction, a theory.  Anderson’s elegant experimental work showed anti-matter for the first time; it confirmed Dirac’s theory.

Similarly, Albert Einstein’s Theory of General Relativity and Arthur Eddington’s confirmation…  or Murray Gell-Mann’s theoretical quarks, and the Stanford Linear Accelerator team (Henry Kendall, Jerome Friedman and Richard Taylor) who actually found them…

Why do theorists become famous, while experimentalists don’t?  Ashutosh Jogalekar looks at “Theorists, experimentalists and the bias in popular physics.”


As we note that it’s all about the story, we might send nourishing birthday wishes to Sir Frederick Gowland Hopkins; he was born on this date in 1861.  A chemist by training, Hopkins was fascinated from an early age by physiology.  He succeeded in marrying the two passions– and helping to create the field of Biochemistry (of which he was the first professor at Cambridge).

Hopkins discovered the amino acid tryptophan and the anti-oxydent glutathione.  But he is surely best remembered for his discovery of the “nutrient factors,” now known as “vitamins,” essential in animal diets to maintain health– work for which he received the Nobel Prize in Physiology or Medicine in 1929.



Written by LW

June 20, 2013 at 1:01 am

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