A Billion Heartbeats

Interesting. As animals get bigger, from tiny shrew to huge blue whale, pulse rates slow down and life spans stretch out longer, conspiring so that the number of heartbeats during an average stay on Earth tends to be roughly the same, around a billion. And … … the surface area a creature uses to dissipate […]


Fantastic. Spirograph – @GeoGebra Tube http://t.co/psD72mnc full frontal trochoid features. Maybe purges the obsession. — John Golden (@mathhombre) February 6, 2013 Questions for students: What’s with that fraction on the left side? What does that do? How do I get a graph with 7 “arms”? What is a the graph with 2 arms called? How […]

Followup to Favorite Proof

Results to Favorite Proof: A pretty common theme: Simplicity in presentation or Visual Component. <snark>Note: No 2 column geometry proofs are found in this list.</snark>