Colorful sea in milk

Warn­ing! Only un­der adult su­per­vi­sion.

Equip­ment

• dif­fer­ent­ly-col­ored al­co­hol-based mark­ers;
• cot­ton disk;
• deep plate;
• milk.

Step-by-step in­struc­tions

Use mark­ers to thor­ough­ly sat­u­rate a cot­ton disk with ink, then toss the disk into a plate of milk: the milk be­comes mul­ti­col­ored!

Sci­en­tif­ic de­scrip­tion

The mark­er ink per­me­ates into the cot­ton fibers that make up the disk. As soon as the cot­ton disk comes into con­tact with the milk, some of the ink, which is less dense than the milk, floats to the sur­face. Sur­face ten­sion stretch­es the ink into a thin film on the milk’s sur­face, as the dye mol­e­cules in­ter­act with the milk mol­e­cules more strong­ly than with each oth­er.

More safe ex­per­i­ments are wait­ing for you in the MEL STEM sub­scrip­tion.