Make milk into marbles

How can something so common as milk turn instantly into a hard ball?

Alginate.

This critical ingredient is in everything from casts to Tums to silk screening gear. It is also the magic powder dropped into this kitchen sink science experiment.

So, what is alginate? Sodium alginate is the sodium salt of alginic acid. Found naturally in seaweed, it is used here for its rapid agglutination properties. This process is accelerated by the vinegar. The sugar provides an additional binding agent for the balls.

If you've tried this, we'd love to hear about it. There might even be a free t-shirt in it for you if your video is stellar.