{"id":16239,"date":"2026-06-15T22:22:41","date_gmt":"2026-06-15T20:22:41","guid":{"rendered":"https:\/\/www.evoluscience.fr\/?page_id=16239"},"modified":"2026-06-15T22:27:12","modified_gmt":"2026-06-15T20:27:12","slug":"activite-2","status":"publish","type":"page","link":"https:\/\/www.evoluscience.fr\/index.php\/sixieme\/partie-4\/chapitre-2-les-melanges\/activite-2\/","title":{"rendered":"Activit\u00e9 2"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><em>A bord de l\u2019ISS, l\u2019eau est n\u00e9cessaire mais extr\u00eamement rare. Elle est trait\u00e9e et r\u00e9utilis\u00e9e en permanence.<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Pour 6 astronautes pendant 300 jours, on a besoin de &nbsp;5400 litres d&rsquo;eau.<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Impossible \u00e0 stocker, \u00e0 transporter, ou \u00e0 renouveler de mani\u00e8re r\u00e9guli\u00e8re.&nbsp;Le recyclage devient donc une question de survie.<\/em><\/p>\n\n\n\n<div style=\"height:46px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-vivid-green-cyan-color has-text-color has-link-color wp-elements-7c2e0a30cccfb447d9da949b21377d58 wp-block-paragraph\">Comment s\u00e9parer les constituants de l\u2019eau usag\u00e9e&nbsp;?<\/p>\n\n\n\n<p class=\"has-background wp-block-paragraph\" style=\"background-color:#fbc49c\">Activit\u00e9 2&nbsp;: S\u00e9paration des constituants d\u2019un m\u00e9lange<\/p>\n\n\n\n<div style=\"height:57px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Comp\u00e9tences travaill\u00e9es&nbsp;:<\/em><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em> R\u00e9aliser une hypoth\u00e8se<\/em><\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em>Suivre un protocole<\/em><\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em>R\u00e9aliser une exp\u00e9rience<\/em><\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em>Travailler en groupe<\/em><\/li>\n<\/ul>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">L\u2019eau r\u00e9utilis\u00e9e dans l\u2019ISS provient&nbsp;de :<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>L\u2019urine des astronautes (oui, vraiment).<\/li>\n\n\n\n<li>La sueur \u00e9vapor\u00e9e par le corps.<\/li>\n\n\n\n<li>L\u2019humidit\u00e9 pr\u00e9sente dans l\u2019air ambiant.<\/li>\n\n\n\n<li>La vapeur d\u2019eau issue de la respiration.<\/li>\n<\/ul>\n\n\n\n<div style=\"height:65px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">En simplifiant, les techniques utilis\u00e9es sont similaires aux stations d\u2019\u00e9puration (mais en plus performantes&nbsp;!).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Nous allons partir de la situation dans laquelle nous voudrions rendre le m\u00e9lange h\u00e9t\u00e9rog\u00e8ne eau boueuse plus homog\u00e8ne en s\u00e9parant l\u2019eau de la boue.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Formuler une ou des hypoth\u00e8ses concernant la mani\u00e8re dont on pourrait rendre le m\u00e9lange homog\u00e8ne (s\u00e9paration de l\u2019eau et de la boue).<\/li>\n<\/ol>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Nous allons r\u00e9aliser deux techniques de s\u00e9paration.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Technique 1&nbsp;: D\u00e9cantation&nbsp;: Technique permettant la s\u00e9paration, par diff\u00e9rence de gravit\u00e9, des constituants d\u2019un m\u00e9lange h\u00e9t\u00e9rog\u00e8ne (dont un liquide).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Suivre le protocole&nbsp;d&rsquo;une d\u00e9cantation&nbsp;:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>placer dans un b\u00e9cher de l&rsquo;eau et de la terre<\/li>\n\n\n\n<li>m\u00e9langer l&rsquo;int\u00e9rieur du b\u00e9cher<\/li>\n\n\n\n<li>observer pendant quelques minutes comment r\u00e9agit le m\u00e9lange<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">2. Expliquer ce qui se passe dans le b\u00e9cher lors de la d\u00e9cantation au bout de 5 minutes.<\/p>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Technique 2&nbsp;: Filtration&nbsp;: Technique permettant de s\u00e9parer les solides des liquides ou des gaz \u00e0 l&rsquo;aide d&rsquo;un milieu filtrant qui laisse passer le fluide mais retient les solides.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Suivre le protocole&nbsp;d&rsquo;une filtration classique&nbsp;:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>placer de mani\u00e8re stable l&rsquo;entonnoir au-dessus du b\u00e9cher ou de l&rsquo;erlenmeyer qui va recevoir le filtrat&nbsp;;<\/li>\n\n\n\n<li>placer un papier filtre correctement pli\u00e9 dans l&rsquo;entonnoir&nbsp;;<\/li>\n\n\n\n<li>introduire le m\u00e9lange h\u00e9t\u00e9rog\u00e8ne dans le filtre, puis attendre que la phase liquide descende dans le b\u00e9cher ou dans l&rsquo;erlenmeyer.<\/li>\n<\/ul>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img alt=\"\" loading=\"lazy\" decoding=\"async\" width=\"603\" height=\"452\" src=\"https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2026\/06\/image-8.png\" alt=\"\" class=\"wp-image-16247\" srcset=\"https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2026\/06\/image-8.png 603w, https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2026\/06\/image-8-300x225.png 300w, https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2026\/06\/image-8-520x390.png 520w\" sizes=\"auto, (max-width: 603px) 100vw, 603px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">3. Expliquer ce qui se passe dans le b\u00e9cher lors de la filtration.<\/p>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Plan B s\u2019il n\u2019est pas possible de r\u00e9aliser l\u2019exp\u00e9rience&nbsp;:<\/p>\n\n\n\n<figure class=\"wp-block-video\"><video height=\"720\" style=\"aspect-ratio: 1280 \/ 720;\" width=\"1280\" controls src=\"https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2026\/06\/6eme-Decantation-puis-filtration-dun-melange-heterogene.mp4\"><\/video><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Source : <a href=\"https:\/\/www.youtube.com\/watch?v=aJSs0CORGNA\">https:\/\/www.youtube.com\/watch?v=aJSs0CORGNA<\/a><\/p>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Pour en savoir plus&nbsp;: <a href=\"https:\/\/www.aquafontaine.fr\/leau-dans-lespace-comment-les-astronautes-la-recyclent-ils\/#:~:text=Distillation%20sous%20vide%20%3A%20l'eau,hydrog%C3%A8ne%20pour%20neutraliser%20toute%20contamination\">https:\/\/www.aquafontaine.fr\/leau-dans-lespace-comment-les-astronautes-la-recyclent-ils\/#:~:text=Distillation%20sous%20vide%20%3A%20l&rsquo;eau,hydrog%C3%A8ne%20pour%20neutraliser%20toute%20contamination<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><a href=\"https:\/\/www.evoluscience.fr\/index.php\/sixieme\/partie-4\/chapitre-2-les-melanges\/activite-2\/conclusion-2\/\" target=\"_blank\" rel=\" noreferrer noopener\"><img alt=\"\" loading=\"lazy\" decoding=\"async\" width=\"538\" height=\"538\" src=\"https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2019\/09\/conclusion.png\" alt=\"\" class=\"wp-image-370\" style=\"width:344px;height:auto\" srcset=\"https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2019\/09\/conclusion.png 538w, https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2019\/09\/conclusion-150x150.png 150w, https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2019\/09\/conclusion-300x300.png 300w, https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2019\/09\/conclusion-520x520.png 520w\" sizes=\"auto, (max-width: 538px) 100vw, 538px\" \/><\/a><\/figure>\n<\/div>\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img alt=\"\" loading=\"lazy\" decoding=\"async\" width=\"735\" height=\"735\" src=\"https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2020\/03\/pjiece_jointe-1.png\" alt=\"\" class=\"wp-image-4366\" style=\"width:435px;height:auto\" srcset=\"https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2020\/03\/pjiece_jointe-1.png 735w, https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2020\/03\/pjiece_jointe-1-300x300.png 300w, https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2020\/03\/pjiece_jointe-1-150x150.png 150w, https:\/\/www.evoluscience.fr\/wp-content\/uploads\/2020\/03\/pjiece_jointe-1-520x520.png 520w\" sizes=\"auto, (max-width: 735px) 100vw, 735px\" \/><\/figure>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>A bord de l\u2019ISS, l\u2019eau est n\u00e9cessaire mais extr\u00eamement rare. Elle est trait\u00e9e et r\u00e9utilis\u00e9e en permanence. Pour 6 astronautes pendant 300 jours, on a besoin de &nbsp;5400 litres d&rsquo;eau. Impossible \u00e0 stocker, \u00e0 transporter,<a class=\"read-more\" href=\"https:\/\/www.evoluscience.fr\/index.php\/sixieme\/partie-4\/chapitre-2-les-melanges\/activite-2\/\">Continue reading<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":16119,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_themeisle_gutenberg_block_has_review":false,"footnotes":""},"class_list":["post-16239","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.evoluscience.fr\/index.php\/wp-json\/wp\/v2\/pages\/16239","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.evoluscience.fr\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.evoluscience.fr\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.evoluscience.fr\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.evoluscience.fr\/index.php\/wp-json\/wp\/v2\/comments?post=16239"}],"version-history":[{"count":0,"href":"https:\/\/www.evoluscience.fr\/index.php\/wp-json\/wp\/v2\/pages\/16239\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.evoluscience.fr\/index.php\/wp-json\/wp\/v2\/pages\/16119"}],"wp:attachment":[{"href":"https:\/\/www.evoluscience.fr\/index.php\/wp-json\/wp\/v2\/media?parent=16239"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}