"Milk Madness" experiment

A sim­ple ex­per­i­ment you can do at home, which will amaze chil­dren and adults alike.

Reagents and equip­ment:

• milk;
• food col­or­ings;
• dish­wash­ing liq­uid;
• pipettes or sy­ringes;
• bowl;
• glass­es;
• cot­ton bud.

Step-by-step in­struc­tions

Put the food col­or­ings in the glass­es and di­lute in a small amount of wa­ter. Pour milk into a bowl, then add the food col­or­ings with a pipette, Then ap­ply the dish­wash­ing liq­uid to the cot­ton bud. Touch the sur­face of the milk with it.

Pro­cess­es de­scrip­tion

Most dish­wash­ing liq­uids con­tain sur­face-ac­tive agents. They are used to re­duce sur­face ten­sion. Milk is a col­loidal so­lu­tion of dif­fer­ent or­gan­ic sub­stances: fats, pro­teins, vi­ta­mins etc, in wa­ter. When the dish­wash­ing liq­uid is added, the bonds hold­ing this so­lu­tion in equi­lib­ri­um shrink and the so­lu­tion “dis­pers­es”. You can’t see this with the naked eye, and so we add the food col­or­ings, which show the sub­stances mov­ing.