Let\u2019s quickly review the major problems faced by classical physics at the turn of the twentieth century:<\/p>\n\n\n\n
1.<\/strong> Classical physics would predict that a blackbody should radiate an infinite amount of UV light. However, hot objects actually produce a limited glow that peaks at a wavelength dependent on temperature and then decays to zero at short wavelengths.<\/p>\n\n\n\n 2.<\/strong> Classical physics would predict that light waves hitting a metal surface should take time to build enough amplitude to shake electrons loose. In addition, the emission of electrons should be dependent on the intensity, and independent of the wavelength of the incident light. However, the photoelectric effect is instantaneous, independent of the intensity, but definitely dependent on wavelength.<\/p>\n\n\n\n 3.<\/strong> Classical physics would predict that atoms shouldn\u2019t last because their electrons would spiral into the nucleus within an instant of their creation. However, everything around us is made of very stable atoms. In addition, classical physics would predict that the light produced by exciting atoms of a certain element should contain all colors of the spectrum. However, the light produced by an element contains only discrete spectral lines that are unique to that element.<\/p>\n\n\n\n All of these problems were resolved in the same exact way. Namely, by using quantization involving Planck\u2019s constant h<\/em> = 6.626 \u00d7 10\u221234<\/sup> J \u00b7 s:<\/p>\n\n\n\n 1.<\/strong> In 1900, Max Planck resolved the Ultraviolet Catastrophe by assuming that the vibrations produced by a blackbody\u2019s harmonic oscillators are quantized by a new constant h<\/em> that was later named in his honor.<\/p>\n\n\n\n 2.<\/strong> In 1905, Albert Einstein solved the mystery of the photoelectric effect by proposing that light is not a wave, but rather a stream of quantized packets of energy (that we now call photons). The energy E<\/em> of each quantum is given by its frequency f<\/em> and Planck\u2019s constant h<\/em>.<\/p>\n\n\n\n 3.<\/strong> In 1913, Niels Bohr proposed to quantize the orbits of the hydrogen atom, thus explaining their stability and the discrete line spectra they emit. Bohr\u2019s quantization condition is that the allowed angular momentum L<\/em> of an orbiting electron is given by L<\/em> = h<\/em>\/2m<\/em>e<\/sub>v<\/em>, where m<\/em>e<\/sub> is the mass of the electron, v<\/em> its velocity, and h<\/em> is again Planck\u2019s constant.<\/p>\n\n\n\n We can thus see the tremendous importance of Planck\u2019s constant as a fundamental characteristic of nature. The existence of Planck\u2019s constant tells us that the universe is not smooth at small scales, but is made of tiny bits. This is very much like the picture in your computer screen: although it looks like a smooth, continuous image, it is actually formed by tiny pixels.<\/p>\n\n\n\n Planck\u2019s constant is in essence a measure of the \u201cgraininess\u201d of the universe at microscopic scales. It is very small\u2014just 6.626 \u00d7 10\u221234<\/sup> J \u00b7 s, but not zero. If it were zero, then the universe would be perfectly continuous, and the predictions of classical physics would work out. However, h<\/em> is not zero, and that makes the world of the microscopic behave in ways we don\u2019t expect at all based on our everyday experiences<\/p>\n","protected":false},"excerpt":{"rendered":" Let\u2019s quickly review the major problems faced by classical physics at the turn of the twentieth century: 1. Classical physics would predict that a blackbody should radiate an infinite amount of UV light. However, hot objects actually produce a limited glow that peaks at a wavelength dependent on temperature and then decays to zero at short […]<\/p>\n","protected":false},"author":1,"featured_media":4179,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[514],"tags":[],"class_list":["post-4400","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-the-principle-of-quantum-physics"],"jetpack_featured_media_url":"https:\/\/workhouse.sweetdishy.com\/wp-content\/uploads\/2024\/09\/science-2.png","_links":{"self":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/4400","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/comments?post=4400"}],"version-history":[{"count":1,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/4400\/revisions"}],"predecessor-version":[{"id":4408,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/4400\/revisions\/4408"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media\/4179"}],"wp:attachment":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media?parent=4400"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/categories?post=4400"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/tags?post=4400"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}