In this experiment you created a gel out of sodium alginate. A gel is a soft substance that has the properties of both liquids and solids. In this experiment, long chains of repeating molecules in the alginate – called polymers – became tangled into a net or mesh. How did it work? When you added calcium chloride, the calcium ions in the solution crosslinked the polymers in the alginate, attaching them to each other at many points. This cross-linking created a flexible, soft solid – a gel bead. During the longer soak, more calcium ions were able to move further into the mesh of the gel bead, resulting in more cross-linking and a firmer texture. Alginate is made from algae. There are many common gels made from algae that are used in foods, medicine, and other applications. Alginate and the algae-based polymers xanthan gum and carageenan are used to improve the textures of foods such as chicken nuggets and ice cream.