Lab 1. Diffusion And Osmosis Answers

Totila Eadweard Muybridge, the man who showed that the horses 'flying'

In 1872, a controversy facing the horse lovers in California. Leland Stanford ( photo ), businessman and governor of California, founder of the university that bears his name and a group of his friends claimed that there was a point during the trot or gallop, the horse did not support any town on the ground. Another group, which included James Keene, president of San Francisco Bag, categorically denied that possibility. There was no way to prove who was right, until Leland Stanford devised a simple experiment.

Stanford commissioned a British photographer based in California, named Eadweard Muybridge ( photo), who tried to capture with his camera the movement of his racehorse Occident.
Without much confidence in the outcome, Muybridge was paid to photograph Occident trotting about 35 km / h at the track in Sacramento. He asked the locals to lend him many sheets and hung them around the track, to create a background on which the silhouette of the horse. Did not try to take pictures with the correct exposure, knowing that the figure would be enough to decide the issue.

His first attempts failed, because the manual shutter was too slow to achieve exposure times as short as needed.

So he invented a mechanical shutter, consisting of two pairs of sheets of wood that slid vertically through the slots in a frame and bared an aperture of 20 cm, by passing light. This system achieved an exposure time of 1 / 500 of a second. The resulting photographs gave reason to Stanford: the horse is completely separated from the ground when he trotted quickly.

Stanford, impressed, ordered a photo studio to capture all the subsequent stages of the movement of a horse. The experiments were resumed in Stanford's ranch during the summer of 1878. Although a slight under exposure, the resulting series of photographs clearly showing all the movements of a Kentucky race horse named Sally Gardner. Muybridge negative painted only saw the silhouette of the horse, whose legs take positions inconceivable. The sequence of 12 photographs were approximately half a second.

In October 1878, Scientific American magazine published six engravings on extended negative Muybridge photographs, which showed a horse moving at the pace and trot. The proposed magazine readers to cut out the pictures and the ride on a zoetrope, a cylinder that produces the illusion of motion when turning and the images are viewed through a side slot. The effect achieved is based on the persistence of vision. When the human eye sees a series of images that occur rapidly (ten or more per second) is the impression of continuous motion. However, if the images were not separated from each other, is would be blurred.

After reading this article, Muybridge thought it could improve the results by projecting the images onto a screen and invented a light projector, which gave the name of Zoopraxiscope.

In 1888, he showed his photographs of horses to Thomas Edison, the inventor of the phonograph, and suggested the possibility of combining their inventions to show sound images. Although the idea was not practical, Edison did employ a series of photographs of horses in his kinetoscope, apparatus precursor film projector.