Lesson 6.12: Natural Resources & Synthetic Materials

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Natural Resource Used to Make the Gel Worm – Sodium Alginate

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.

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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.

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Sodium alginate Polymer

Both models show:

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

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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.