Changes

Einstein compared the effects of large objects on space and time to the way that a large ball placed on a sheet of rubber stretches the material and causes it to sag, and drew the analogy with the way stars and planets warp space-time. A smaller ball rolling along the sagging fabric will be drawn towards the larger ball, in the same way that the Earth is drawn towards the sun, but will not fall into it as long as it continues to move at sufficient speed. This was a change in thinking from the Newtonian cosmos, in which gravity was viewed purely as an attractive force between bodies.

Einstein compared the effects of large objects on space and time to the way that a large ball placed on a sheet of rubber stretches the material and causes it to sag, and drew the analogy with the way stars and planets warp space-time. A smaller ball rolling along the sagging fabric will be drawn towards the larger ball, in the same way that the Earth is drawn towards the sun, but will not fall into it as long as it continues to move at sufficient speed. This was a change in thinking from the Newtonian cosmos, in which gravity was viewed purely as an attractive force between bodies.

Einstein's statistical explanation of Brownian motion (the random movement of microscopic particles mixed in with pollen) is sometimes credited with helping to confirm the atomic theory at a time when some scientists argued against it.<ref>Cassidy, David (2004). [http://www.aip.org/history/einstein/essay-brownian.htm "Einstein on Brownian motion"].  [http://www.aip.org/history/einstein/great1.htm American Institute of Physics/AIP Center for History of Physics/Albert Einstein-Image and Impact/The Great Works I].  Retrieved on January 24, 2014.]</ref> Most scientists had accepted atomic theory a century earlier.

Einstein's statistical explanation of Brownian motion (the random movement of microscopic particles mixed in with pollen) is sometimes credited with helping to confirm the atomic theory at a time when some scientists argued against it.<ref>Cassidy, David (2004). [http://www.aip.org/history/einstein/essay-brownian.htm "Einstein on Brownian motion"].  [http://www.aip.org/history/einstein/great1.htm American Institute of Physics/AIP Center for History of Physics/Albert Einstein-Image and Impact/The Great Works I].  Retrieved on January 24, 2014.</ref> Most scientists had accepted atomic theory a century earlier.

Einstein also published a heuristic explanation of the photoelectric effect in which light has particle like properties as well as wave like properties. According to [[Maxwell's Equations]], light is a wave so one might expect that increasing the intensity of light should increase the number of electrons emitted from metal. The German physicist Lénard did an experiment proving that this was not true. Einstein argued that the experiment was consistent with [[Max Planck]]'s hypothesis that light is quantized and different particles of light or photons have different frequencies. Therefore, increasing the intensity of low frequency photons has no effect, while using a higher (blue or ultra violet) frequency of light does cause more electrons to be emitted. The formula Einstein used to explain this was Planck's formula ''e'' = ''hf'', where ''h'' is Planck's constant and ''f'' is the frequency.<ref>Davis, Warren, PhD. (2008 or before).  [http://www.physlink.com/Education/AskExperts/ae24.cfm?CFID=8792067&CFTOKEN=36662276 "What is the photoelectric effect?"]  PhysLink.com.  Retrieved on January 24, 2015.</ref>

Einstein also published a heuristic explanation of the photoelectric effect in which light has particle like properties as well as wave like properties. According to [[Maxwell's Equations]], light is a wave so one might expect that increasing the intensity of light should increase the number of electrons emitted from metal. The German physicist Lénard did an experiment proving that this was not true. Einstein argued that the experiment was consistent with [[Max Planck]]'s hypothesis that light is quantized and different particles of light or photons have different frequencies. Therefore, increasing the intensity of low frequency photons has no effect, while using a higher (blue or ultra violet) frequency of light does cause more electrons to be emitted. The formula Einstein used to explain this was Planck's formula ''e'' = ''hf'', where ''h'' is Planck's constant and ''f'' is the frequency.<ref>Davis, Warren, PhD. (2008 or before).  [http://www.physlink.com/Education/AskExperts/ae24.cfm?CFID=8792067&CFTOKEN=36662276 "What is the photoelectric effect?"]  PhysLink.com.  Retrieved on January 24, 2015.</ref>