{"id":18322,"date":"2014-07-06T17:17:06","date_gmt":"2014-07-06T16:17:06","guid":{"rendered":"https:\/\/communicatescience.com\/zoonomian\/?p=18322"},"modified":"2024-03-15T15:43:58","modified_gmt":"2024-03-15T15:43:58","slug":"virtual-recreation-of-newtons-experimentum-crucis-two-prism-experiment","status":"publish","type":"post","link":"https:\/\/communicatescience.com\/zoonomian\/2014\/07\/06\/virtual-recreation-of-newtons-experimentum-crucis-two-prism-experiment\/","title":{"rendered":"Virtual Recreation of Newton’s Two Prism Experiment"},"content":{"rendered":"
\n
\"Dispersion<\/a><\/figure>\n<\/div>\n\n\n

I began by testing if the physically based render program Luxrender\u00a0<\/a> can make a believable simulation of white light passing through a prism.\u00a0 <\/p>\n\n\n\n

Unbiased render engines like Luxrender send out many virtual photons and calculate their paths according to physical laws, and as the ray-tracing algorithm includes colour dispersion, it should work.<\/p>\n\n\n\n

Experimentum Crucis<\/h2>\n\n\n\n

Adding a second prism gives us Isaac Newton’s ‘Experimentum Crucis’: one of a series of experiments performed by Newton in 1666 and reported in a letter to the Royal Society in 1671 (1), showing how white light is composed of a range of colours separable by a prism.\u00a0 <\/p>\n\n\n\n

Newton then demonstrated the colours were a property of the light, not the prism, by using a slit to isolate an individual colour from one prism, and passing it through a second where no further separation of colours occurs – the second prism just refracts the single colour to one side.\u00a0 Here is Newton’s own drawing of his two-prism experiment.<\/p>\n\n\n

\n
\"Experimentum<\/a>
Experimentum Crucis<\/figcaption><\/figure>\n<\/div>\n\n\n

Virtual set-up and approximations<\/h2>\n\n\n\n

My distances and prism sizes are not accurate, but the simulation still works. \u00a0 Also, Newton used the sun as a light source: passed through a slit before the first prism or focused through a lens. By contrast, my source is a small rectangular surface radiating in all forward directions followed by a collimating tunnel.<\/p>\n\n\n\n

If the real or simulated light source is too ill-defined or unfocused, the separation in the spectrum can look superficially reasonable, but actually comprise several fuzzy overlapping spectra.\u00a0\u00a0 As a result, running without the collimator caused the green band to split into further colours. \u00a0 That said, it’s worth remembering that while Newton reported seeing seven colours, the actual spectrum is a continuum of wavelengths, so a single colour will in fact be made of a range of further dispersible shades – we just don’t discern it.<\/p>\n\n\n\n

Results<\/h2>\n\n\n\n

Here is a close-up of the isolating slit and the green spectral ‘line’ deviated but not dispersed by the second prism.  I’ve also in this picture turned out the background light used solely for dramatic effect in the first picture.<\/p>\n\n\n

\n
\"Dispersion<\/a><\/figure>\n<\/div>\n\n\n

And here are wireframe pics of the layout (scene created in Poser and linked to Luxrender via Reality):<\/p>\n\n\n

\n
\"Screen-Shot-2014-06-16-at-01.43\"<\/a><\/figure>\n<\/div>\n\n
\n
\"Screen-Shot-2014-06-16-at-01.52\"<\/a><\/figure>\n<\/div>\n\n
\n
\"Screen-Shot-2014-06-21-at-03.15\"<\/a><\/figure>\n<\/div>\n\n\n

Other Observations<\/h2>\n\n\n\n

An interesting feature of this type of modelling is the need for a so-called Tone Mapping process. This requires the multiple wavelengths to which the ray-tracing maths is applied to simulate dispersion are translated into the red, blue, and green (RGB) that the computer monitor can display.<\/p>\n\n\n\n

This sort of progam is limited as a virtual optical bench.\u00a0 Luxrender cannot, for example, calculate the quantum probability amplitudes necessary to simulate interference as seen in the double slit experiment<\/a>.<\/p>\n\n\n\n

References<\/strong><\/p>\n\n\n\n

(1)  doi: 10.1098\/rstl.1671.0072 <\/span> Phil. Trans.<\/abbr> 1 January 1671 <\/span> vol. 6 <\/span> no. 69-80 <\/span> 3075-3087<\/span><\/cite> <\/p>\n\n\n\n

Also of interest: <\/strong><\/p>\n\n\n\n

Experimentum Crucis<\/div>\n\n\n\n
\n
J. A. Lohne<\/div>\n
Notes and Records of the Royal Society of London<\/cite>, Vol. 23, No. 2 (Dec., 1968), pp. 169-199<\/div>\n
Published by: The Royal Society<\/a><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

I began by testing if the physically based render program Luxrender\u00a0 can make a believable simulation of white light passing through a prism.\u00a0 Unbiased render engines like Luxrender send out many virtual photons and calculate their paths according to physical laws, and as the ray-tracing algorithm includes colour dispersion, it should work. Experimentum Crucis Adding … Continue reading Virtual Recreation of Newton’s Two Prism Experiment<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"ngg_post_thumbnail":0,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[102,1109,11,1],"tags":[1136,1106,1395,1394,816,1393],"class_list":["post-18322","post","type-post","status-publish","format-standard","hentry","category-biography","category-history-of-science-history","category-physics","category-uncategorized","tag-color","tag-colour","tag-dispersion","tag-luxrender","tag-newton","tag-prism"],"aioseo_notices":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pkpOr-4Lw","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/posts\/18322","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/comments?post=18322"}],"version-history":[{"count":4,"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/posts\/18322\/revisions"}],"predecessor-version":[{"id":18955,"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/posts\/18322\/revisions\/18955"}],"wp:attachment":[{"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/media?parent=18322"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/categories?post=18322"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/communicatescience.com\/zoonomian\/wp-json\/wp\/v2\/tags?post=18322"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}