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Chapter 6, Lesson 12 Multimedia

Natural resource used to make the gel worm
Sodium alginate

Brown Seaweed

Sodium alginate is made from brown seaweed

The harvested seaweed is:

  • Cut and mixed with water to make a thick gel
  • Diluted with more water and filtered
  • Mixture evaporated and further processed to make sodium alginate powder

Natural resource used to make the gel worm
Calcium chloride


Calcium chloride is made from limestone, which is calcium carbonate.

  • Limestone is a sedimentary rock, formed from the shells and skeletons of ancient sea creatures.
  • The mined limestone is reacted with hydrochloric acid or sodium chloride to make the calcium chloride

Sodium alginate polymer

Sodium Alginate

Both models show:

  • Sodium ion has a positive charge
  • Place where it's bonded to the molecule has a negative charge

Crosslinking sodium alginate

Crosslinking Sodium Alginate
  • Calcium ions have two positive charges
  • Calcium ions bond to two sodium alginate molecules crosslinking the chains
  • Many crosslinking connections make the sodium alginate thicken to become a gel