Over 100,000 exhibits were on display at the Great exhibition. To achieve some semblance of order, a system of classification had to be devised. After months of work, a thirty part system of classification was eventually adopted, divided into 4 main sections: raw materials, machinery, manufactures and fine arts.
Ground-floor plan of the Crystal Palace, Great Exhibition building, 1851, "copied by permission from the official plans". Lithographed by Day and Son. Source: Manchester Metropolitan University - http://ibs001.colo.firstnet.net.uk/mmu/image.php?i=578&r=1&t=4&x=6
The Machinery Courts
The Machinery Courts at the Great Exhibition drew the largest crowds of people and Queen Victoria herself visited these more times than any other section of the Exhibition. She wrote in her journal:
"Went to the machinery part where we remained two hours, and which is excessively interesting and instructive...what used to be done by hand and take months doing is now accomplished in a few minutes by the most beautiful machinery...We came home at a 1/4 to 12, and I felt quite done and exhausted, mentally exhausted" .
The machinery exhibits similarly received the longest and most detailed descriptions and illustrations in the Official Catalogue for the Exhibition. A good example is provided by the illustration below which appeared in the Official Catalogue with the commentary: "The Queen in the machine room examining the vertical printing machine invented by Applegarth for the Times newspaper. In the left-hand corner is a representation of Black's patent folding machine; while on the other side, we have a view of a carding machine, one of a series of instruments used in woolen manufacture".
Illustration from the Official Catalogue. Source University of Glasgow library - http://special.lib.gla.ac.uk/teach/century/paris.html
Machinery in motion
A number of the machines displayed were actually in motion, powered by isolated pipes beneath the floor boards which connected to a small engine house at the north-west corner of the exhibition building. The machines in this section of the building were partitioned from the rest to contain the noise and dust emitted by them.
The Great Exhibition: Moving Machinery; Louis Haghe c.1851-52. Comissioned by Prince Albert in 1851 and still in the Royal Collection. Prince Albert commissioned fifty watercolours of the Great Exhibition, to be reproduced by Dickinson Bros in chromolithography, a new mechanical colour-printing process in keeping with the aims of the exhibition itself. The lettering of the lithograph points out that such machines could be used by untrained men to do work which formerly had to be carried out by skilled workmen at high wages.
The cotton machinery of Hibbert, Platt & Sons were a highlight of this section: a series of 15 machines in one room demonstrating the cotton spinning process as cotton was "opened, carded, doubled, spun, warped and woven, all before the eyes of the visitors" who were kept away from the machinery by an iron railing.
Hibert, Platt & Son's cotton machines. Illustrated London News, 23 August 1851.
Another symbol of British industrial success was the Harrison Power Loom, also in the machinery in motion section of the Exhibition. By the early nineteenth century, the spinning of yarn had been mechanised, but weaving remained largely a handicraft. In 1820, British cotton-spinning mills employed 110,000 workers, but over 250,000 handloom weavers still worked at home.  This was partly because devising a power-driven loom to handle dozens of warp threads without breakage proved difficult. As power looms became more common they led to great suffering among handloom workers. During downturns in business, manufacturers laid off independent hand-weavers, using them as a 'buffer' in order to keep the costly machines busy. For this reason the installation of new looms often met violent opposition from handloom weavers. However, by 1851 practical power looms had become widespread and hand-weaving, except for complex or specialised fabrics, was almost extinct.
The Harrison Power Loom, displayed at the Great Exhibition as part of the section entitled "Machinery in Motion". Source: Science Museum/Science and Society Picture Library - http://www.makingthemodernworld.org.uk/icons_of_invention/technology/1820-1880/IC.004/
Aside from machines in motion, there were many and varied examples of British industrial prowess: a printing machine that could churn out five thousand copies of the Illustrated London News an hour (shown below), a steam powered hydraulic lever used to raise the 1,500 iron ton tubes of Robert Stephenson's railway bridge over the Menai Straits and a revolutionary agricultural reaping machine from the United States.
Printing machine for the Illustrated London News from 'The Illustrated Exhibitor: guide to the Great Exhibition, 1851. Source: British Libraryhttp://www.bl.uk/learning/images/victorian/illustratedexhibitor/large102701.html
All these machines were designed to exhibit the full extent of Britain's industrial might and ingenuity to the people of Britain and of the world. And appeal to them it did. Henry Mayhew, English social commentator and founder of Punch, described how on shilling days, visitors pressed two and three deep to watch the machinery in motion. 
 de Mare, Eric, London 1851: The Year of the Great Exhibition; The Folio Press (1973) pg 54
 The illustrated exhibitor ... comprising sketches ... of the principal exhibits of the Great Exhibition of ... 1851 London, 185. Taken from the University of Glasgow website: http://special.lib.gla.ac.uk/teach/century/paris.html
 Making the Modern World website at the Science Museum of London: http://www.makingthemodernworld.org.uk/icons_of_invention/technology/1820-1880/IC.004/
 Auerbach, Jeffrey, The Great Exhibition of 1851: A Nation on Display; Yale University Press (1999) pg 106