{"id":2149,"date":"2024-10-05T13:57:50","date_gmt":"2024-10-05T11:58:27","guid":{"rendered":"https:\/\/experiments.school\/?post_type=product&p=2149"},"modified":"2024-10-05T13:58:27","modified_gmt":"2024-10-05T11:58:27","slug":"052-spread-of-a-substance-on-the-water-surface","status":"publish","type":"product","link":"https:\/\/experiments.school\/en\/product\/052-spread-of-a-substance-on-the-water-surface\/","title":{"rendered":"052 – Spread of a substance on the water surface"},"content":{"rendered":"","protected":false},"excerpt":{"rendered":"

Propulsion by recoil\u00a0\u00a0<\/strong><\/h2>\n

Washing-up liquid or alcohol on water\u00a0\u00a0<\/strong><\/h2>\n

 <\/p>\n

Introduction to:\u00a0<\/span>\u00a0<\/span><\/h2>\n
    \n
  • Recoil principle\u00a0<\/span>\u00a0<\/span><\/li>\n
  • Surface tension\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n[video width=\"1920\" height=\"1080\" mp4=\"https:\/\/experiments.school\/wp-content\/uploads\/2024\/09\/052-video-end.mp4\"][\/video]\n

     <\/p>\n

    Material:\u00a0<\/span>\u00a0<\/span><\/h2>\n
      \n
    • Styrofoam board (thin, thickness approx. 2 mm, e.g. from a fast food box) \/ light wood \/ cardboard\u00a0<\/span>\u00a0<\/span><\/li>\n
    • Scissors \/ sharp knife\u00a0<\/span>\u00a0<\/span><\/li>\n
    • Washing-up liquid or liquid detergent \/ disinfectant \/ alcohol (e.g. ethanol, methanol, propanol)\u00a0<\/span>\u00a0<\/span><\/li>\n
    • Large container with water\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

      perhaps:\u00a0<\/span>\u00a0<\/span><\/p>\n

        \n
      • a piece of paper\u00a0<\/span>\u00a0<\/span><\/li>\n
      • Match\u00a0<\/span>\u00a0<\/span><\/li>\n
      • Glue\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

        Instructions:\u00a0<\/span>\u00a0<\/span><\/h2>\n
          \n
        • Cut out a rectangular plate in the shape of a boat from the polystyrene. <\/span>\u00a0<\/span><\/li>\n
        • Cut a thin channel with a hole at the beginning in the boat.\u00a0<\/span>\u00a0<\/span><\/li>\n
        • Decorate the boat as you like with a small sail.\u00a0<\/span>\u00a0<\/span><\/li>\n
        • Check if the boat floats.\u00a0<\/span>\u00a0<\/span><\/li>\n
        • Add a drop of dish soap to the hole.\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

          Observation:\u00a0<\/span>\u00a0<\/span><\/h2>\n
            \n
          • The boat starts moving forward with a jerk. <\/span>\u00a0<\/span><\/li>\n<\/ul>\n

            Explication:<\/span>\u00a0<\/span><\/h2>\n
              \n
            • Both a drop of dish soap and a drop of alcohol spread evenly on a water surface.\u00a0<\/span>\u00a0<\/span><\/li>\n
            • The reasons are differences in the density and surface tension as well as the specific surface energy of the substances. <\/span>\u00a0<\/span><\/li>\n
            • The fuel can only spread backwards through the slot in the boat, resulting in a driving force to the front (recoil force).<\/span>\u00a0<\/span><\/li>\n
            • After some time, the alcohol dissolves in the water and the experiment can be carried out again. Not so with washing-up liquid, where the experiment can only be carried out once.<\/li>\n<\/ul>\n","protected":false},"featured_media":2151,"template":"","meta":[],"product_brand":[],"product_cat":[945,924,882],"product_tag":[],"class_list":{"0":"post-2149","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-15-surface-tension-adhesion","7":"product_cat-8-momentum-conservation-of-momentum","8":"product_cat-j-physics-of-the-kitchen","9":"","10":"woocommerce-text-align-left","11":"woocommerce-image-align-center","13":"first","14":"instock","15":"shipping-taxable","16":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/experiments.school\/en\/wp-json\/wp\/v2\/product\/2149","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/experiments.school\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/experiments.school\/en\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/experiments.school\/en\/wp-json\/wp\/v2\/media\/2151"}],"wp:attachment":[{"href":"https:\/\/experiments.school\/en\/wp-json\/wp\/v2\/media?parent=2149"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/experiments.school\/en\/wp-json\/wp\/v2\/product_brand?post=2149"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/experiments.school\/en\/wp-json\/wp\/v2\/product_cat?post=2149"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/experiments.school\/en\/wp-json\/wp\/v2\/product_tag?post=2149"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}