{"id":4733,"date":"2024-12-03T00:45:17","date_gmt":"2024-12-02T23:45:17","guid":{"rendered":"https:\/\/eva.louis-le-grand.net\/maths\/?p=4733"},"modified":"2024-12-03T00:45:17","modified_gmt":"2024-12-02T23:45:17","slug":"message-en-bulles-ephemeres","status":"publish","type":"post","link":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/2024\/12\/03\/message-en-bulles-ephemeres\/","title":{"rendered":"Message en bulles \u00e9ph\u00e9m\u00e8res"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"342\" src=\"https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/bulles-logo-1024x342.jpg\" alt=\"\" class=\"wp-image-4734\" srcset=\"https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/bulles-logo-1024x342.jpg 1024w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/bulles-logo-300x100.jpg 300w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/bulles-logo-768x256.jpg 768w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/bulles-logo-1536x512.jpg 1536w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/bulles-logo.jpg 1589w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Vous avez probablement remarqu\u00e9 que, dans un verre, les bulles semblent souvent na\u00eetre d\u2019un point fixe. Ces bulles de dioxyde de carbone (CO2), dissous dans le liquide, forment des colonnes verticales qui montent le long des parois du verre, comme si elles \u00e9mergeaient toutes d\u2019un m\u00eame endroit pour atteindre la surface.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u00c0 la base de chaque colonne de bulles, on trouve une minuscule particule de mati\u00e8re, souvent invisible, qui agit comme un d\u00e9clencheur connu sous le nom de \u00ab\u00a0sites de nucl\u00e9ation\u00a0\u00bb. Pour des raisons li\u00e9es \u00e0 la physique des interfaces, ces particules microscopiques capturent le CO2 dissous, permettant ainsi la formation et la lib\u00e9ration des bulles.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Mettons \u00e0 profit ce ph\u00e9nom\u00e8ne pour faire naitre des bulles o\u00f9 l&rsquo;on souhaite. Dans un verre \u00e0 fond plat, on va cr\u00e9er des sites de nucl\u00e9ation aux endroits d\u00e9sir\u00e9s. Remplir le verre de g\u00e9latine m\u00e9lang\u00e9e \u00e0 un peu d&rsquo;eau puis renverser. Laisser s\u00e9cher. Remplir le r\u00e9cipient d&rsquo;eau gazeuse type limonade. Avec la pointe d&rsquo;un couteau gratter le fond ce qui va g\u00e9n\u00e9rer des sites de nucl\u00e9ation auxquels les bulles s&rsquo;accrocheront. Elles grandissent jusqu&rsquo;\u00e0 devenir assez grosses pour pr\u00e9f\u00e9rer s&rsquo;\u00e9lever que de rester accroch\u00e9e. A cet instant les forces s&rsquo;\u00e9galisent entre pouss\u00e9e d&rsquo;archim\u00e8de sur la bulle (4\/3 pi d3) et la diff\u00e9rence de tension superficielle \u00e0 l&rsquo;interface entre la bulle et la surface du site de nucl\u00e9ation par rapport \u00e0 l&rsquo;eau.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"490\" src=\"https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/message-bulles-1024x490.jpg\" alt=\"\" class=\"wp-image-4736\" srcset=\"https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/message-bulles-1024x490.jpg 1024w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/message-bulles-300x143.jpg 300w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/message-bulles-768x367.jpg 768w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/message-bulles.jpg 1146w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"860\" height=\"585\" src=\"https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/gratte.jpg\" alt=\"\" class=\"wp-image-4737\" srcset=\"https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/gratte.jpg 860w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/gratte-300x204.jpg 300w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/gratte-768x522.jpg 768w\" sizes=\"auto, (max-width: 860px) 100vw, 860px\" \/><figcaption class=\"wp-element-caption\">Screenshot<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"797\" src=\"https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/zoom-bulle-1024x797.jpg\" alt=\"\" class=\"wp-image-4735\" srcset=\"https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/zoom-bulle-1024x797.jpg 1024w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/zoom-bulle-300x234.jpg 300w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/zoom-bulle-768x598.jpg 768w, https:\/\/eva.louis-le-grand.net\/maths\/wp-content\/uploads\/2024\/12\/zoom-bulle.jpg 1396w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">Screenshot<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Vous avez probablement remarqu\u00e9 que, dans un verre, les bulles semblent souvent na\u00eetre d\u2019un point fixe. Ces bulles de dioxyde de carbone (CO2), dissous dans le liquide, forment des colonnes verticales qui montent le long des parois du verre, comme si elles \u00e9mergeaient toutes d\u2019un m\u00eame endroit pour atteindre la surface. \u00c0 la base de [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-4733","post","type-post","status-publish","format-standard","hentry","category-non-classe"],"_links":{"self":[{"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/posts\/4733","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/comments?post=4733"}],"version-history":[{"count":1,"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/posts\/4733\/revisions"}],"predecessor-version":[{"id":4738,"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/posts\/4733\/revisions\/4738"}],"wp:attachment":[{"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/media?parent=4733"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/categories?post=4733"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/eva.louis-le-grand.net\/maths\/index.php\/wp-json\/wp\/v2\/tags?post=4733"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}