The year 1831 in science and technology involved some significant events, listed below.

Astronomy

• January 7 – Great Comet of 1831 (C/1831 A1, 1830 II) first observed by John Herapath.^[1]
• March 7 – Royal Astronomical Society receives its Royal Charter.^[2]
• Heinrich Schwabe makes the first detailed drawing of the Great Red Spot on Jupiter.
• Mary Somerville translates Laplace's Mécanique céleste as The Mechanism of the Heavens.

Biology

• September 1 – Zoological Gardens, Dublin, open in Ireland.^[3]
• Robert Brown found the cell nucleus.

Chemistry

• A. A. Bussy publishes his Mémoire sur le Radical métallique de la Magnésie describing his method of isolating magnesium.
• The Kaliapparat, a laboratory device for the analysis of carbon in organic compounds, is invented by Justus von Liebig.

Exploration

• June 1 – British Royal Navy officer James Clark Ross locates the position of the North Magnetic Pole on the Boothia Peninsula.
• December 27 – Charles Darwin starts his voyage on HMS Beagle from Plymouth.

Medicine

• May 16 – Middlesex County Asylum for pauper lunatics opens at Hanwell near London under the humane superintendence of William Charles Ellis.
• Dr C. Turner Thackrah publishes The Effects of the Principal Arts, Trades, and Professions, and of Civic States and Habits of Living, on Health and Longevity, with a particular reference to the trades and manufactures of Leeds, and suggestions for the removal of many of the agents which produce disease and shorten the duration of life, a pioneering study of occupational and public health in a newly industrialised English city.^[4]

Paleontology

• Henry Witham publishes Observations on fossil vegetables, accompanied by representations of their internal structure, as seen through the microscope in Edinburgh.

Technology

• April 12 – Broughton Suspension Bridge over the River Irwell in England collapses under marching troops.^[5]
• August 29 – Michael Faraday demonstrates electromagnetic induction at the Royal Society of London.^[6] Joseph Henry recognises it at about the same time.
• October 28 – Faraday develops the Faraday Wheel, a homopolar generator.^[7]
• Joseph Henry invents the electric bell.^[8]
• James Meadows Rendel erects the first bascule bridge with a hydraulic mechanism, on the Kingsbridge Estuary in England.^[9]
• William Wallace invents the eidograph.^[10]

Institutions

• September 27 – British Association for the Advancement of Science first meets, in York.^[11]

Awards

• Copley Medal: George Biddell Airy^[12]
• Wollaston Medal (first award): William Smith

Births

• January 20 – Edward Routh (died 1907), Canadian-born English mathematician.
• January 26 – Heinrich Anton de Bary (died 1888), German surgeon, botanist, microbiologist and mycologist.
• February 28 – Edward James Stone (died 1897), English astronomer.
• March 3 – George Pullman (died 1897), American inventor.
• May 16 – David E. Hughes (died 1900), British inventor.
• June 13 – James Clerk Maxwell (died 1879), Scottish-born mathematician.
• August 20 – Eduard Suess (died 1914), Austrian geologist.
• October 6 – Richard Dedekind (died 1916), German mathematician.
• October 15 – Isabella Bird (died 1904), English explorer, writer, photographer and naturalist.
• October 21 – Hermann Hellriegel (died 1895), German agricultural chemist, discoverer of the mechanism by which leguminous plants assimilate the free nitrogen of the atmosphere.
• October 29 – Othniel Charles Marsh (died 1899), American paleontologist.

Deaths

• February 14 – Henry Maudslay (born 1771), English mechanical engineer.
• March 26 - Pierre Amable Jean-Baptiste Trannoy (born 1772), French physician, hygienist and botanist.^[13]
• June 27 – Sophie Germain (born 1776), French mathematician.
• October 14 – Jean-Louis Pons (born 1761, French astronomer.
• December 22 – François Huber (born 1750), blind Swiss naturalist.