The milk production at a dairy farm was low, so the farmer wrote to the local university, asking for help from academia.
A multidisciplinary team of professors was assembled and headed by a theoretical physicist. After two weeks of intensive on-site investigation, the scholars then returned to the university, with their notebooks and laptops filled with data.
Shortly thereafter the physicist returned to the farm, saying to the farmer, “We have found a solution!”
“Wonderful!” came the farmer’s reply.
The physicist continued, “But it only works in the case of spherical cows in a vacuum”.