Invention of Cyanotype Photography in 4.21 min video created by George Eastman House. Sir John Herschel invented the cyanotype in 1842. The process depends on the photochemical reduction of ferric salts into ferrous salts leading to the formation of Prussian…
The Talbot’s Processes explained in 6.36 min video created by George Eastman House. Working in England, at the same time as Daguerre, William Henry Fox Talbot is best known for the invention of the negative/positive photographic process that became the…
The Daguerreotype process explained in 6.18 min video created by George Eastman House. The first commercially successful photographic process was announced in 1839, the result of over a decade of experimentation by Louis Daguerre and Nicéphore Niépce. Unfortunately, Niépce died…
The beginning of photography explained in 6.22 min video created by George Eastman House. From the ancient discovery of the camera obscura to the 18th century mechanical devices used to create silhouettes such as the physionotrace, this initial chapter explores…
The discovery of photographic processes has forever changed our understanding of time. For the first time in history we could see what our ancestors looked like. Watch this excellent Photographic Processes Series production of GeorgeEastmanHouse, made possible by a grant…
The hydrometer is an instrument used in determining the specific gravity of a liquid, such as acids, etc. The specific gravity of any material is the ratio of the weights of equal volumes of the material and water. Thus if…
A galvanometer is an instrument used to detect the presence of an electrical current in a circuit or to measure the value of the current in amperes. The operation of practically all galvanometers is based upon the same principle, and…
How to Make a RheostatIn operating small motors there is as a rule no means provided for regulating their speed, and this often is quite a disadvantage, especially in the case of toy motors such as used on miniature electric locomotives.
How to Make an Anemometer for a Science Project – An Electric Anemometer By Wm. H. Dettman The construction of this instrument is so simple that any amateur can make one and if accurate calibrations are desired, these can be…
A Garden-Bed Scarecrow A very neat and successful scarecrow for garden beds can be made as follows: A number of corks are procured, and a feather is stuck in each end of them, as shown. These are tied to a…