Bee dances.

[Greengage]

Is it a fact that the wagle dance, round dance or sickle dance indicate the location of a food source or is it just a hypothesis.

[Thymallus]

Karl Von Frissch's students challenged him to find a hidden food source by interpreting the bees waggle dance. He did.. So Yes it works, but it's not a 100%. Many bees fail to find the source (more details in Buzz about Bees) and return back to hive...but those that find, learn and return and if the dances continue the number of recruits grow.
The round dance doesn't contain any directional information just FOOD CLOSE TO HIVE...queue general mayhem as anyone who has inadvertent left an open food source in their garden testify to.

[Greengage]

Karl von Frisch was awarded the Nobel Prize for physiology and medicine in 1973 to honour his work on animal behavior, especially his theory that honey bees communicate by a dance language.
Before he was awarded the Nobel prize, a zoologist named Adrian Wenner found that his own experiments went against von Frisch’s predictions. Wenner carried out his own experiments found that the bees were unable to locate the food source with dance alone. Wenner had his own theory that bees located a food source by odour, but subsequent to publishing his paper in Nature with his collaborator Wells (1973) he found himself barred for many years by the editors of major scientific publications from presenting his results. James Gould who also challenged Von Frisch conceded that the design of the experiments of von Frisch had been flawed. Once the dance language hypothesis was adopted by the scientific establishment in animal behaviour as a fact, all challenges to it were summarily brushed aside. Interesting stuff.
http://beesource.com/point-of-view/adrian-wenner/the-honey-bee-dance-language-controversy/
http://www.uky.edu/Classes/ENT/568/Gould%20Dance%20Language.pdf

[Adam]

LASI have observed dances through their glass-fronted hives to locate food sources and how they change over the season around the University in Sussex.
I think I am correct in saying that the distance is actually extended energy rather than actual metres over the ground, so if the wind dropped, then the bees would over-shoot if they were otherwise flying into the wind.