Making Useful Products

Introduction to First Nations Australians' Innovations
- Through observation and experimentation, First Nations Australians transformed natural materials into useful products.

Edible Products
  - First Nations Australians developed complex treatments for tree nuts, removing bitter and toxic compounds.
  - Tree nuts are significant for dietary needs, including carbohydrates and protein.
  - Example: Black bean tree (Castanospermum australe) seeds are toxic in their raw state.
    - Symptoms of poisoning include stomach pain, dizziness, vomiting, and diarrhea.
    - Half a seed can result in hospitalization.
Cooking Process for Black Bean Seeds
  1. Preparation:
     - Cook seeds in a specially prepared fire pit lined with ginger leaves.
     - Cook for several hours to make starch digestible.
  2. Processing:
     - Cooked beans are cracked open, thinly sliced, and pounded to break cell membranes.
  3. Leaching:
     - Smashed seeds placed in a finely woven basket and submerged in a fast-flowing creek for days to wash away soluble toxins.
Final Steps:
- Seeds are dried and ground into flour for baking.
Fermentation for Alcohol Production
  - A chemical change using microorganisms (yeast or bacteria) converts starch or sugar into alcohol (ethanol).
  - Historical context: First Nations Australians fermented beverages before European contact.
  - Example:
    - Cider gum tree (Eucalyptus) used for fermentation.
    - Unique strains of yeast and bacteria investigated.

Way-a Linah
  - Made from the sugar-rich sap of the cider gum tree.
    - Process:
      1. Drill a hole in the tree and collect sap at the base.
      2. Left to ferment using local yeast.
Mangaitch
- Made by soaking banksia cones or nectar-laden flowers in a sugar solution.
- Fermentation occurs over days in a trench lined with bark.

Behavior of Photochromic Glasses
  - Darken in bright sunshine and lighten in low light.
  - Functionality:
    - Plastic lenses use organic materials to darken in UV light.
    - Glass lenses contain silver chloride (AgCl) crystals; UV light facilitates a redox reaction, depositing silver particles that darken the lens.
Reactions During Transition:
  1. $Ag^+ + Cl^- <br>ightarrow Ag + Cl^-$
  2. When moving to shadow:
     - $Cu^{2+} + Ag <br>ightarrow Cu^{+} + Ag^{+}$

Definition and Characteristics of Plastics
- Strong, light, and inexpensive synthetic materials available in various colors and shapes.
- Plastics stem from chemical reactions and are ubiquitous in daily products (e.g., containers, toys, bags).
Polymers and Monomers
  - All plastics are polymers, which consist of repeating units called monomers.
    - Monomers often contain carbon, along with hydrogen, oxygen, chlorine, and nitrogen.
  - Polymerisation: Process of joining monomers into polymers.
    - $ext{Example: Polyvinyl acetate (PVA)}$
Examples of Synthetic Polymers
  1. Polyvinyl Chloride (PVC): Formed from vinyl chloride, used for pipes.
  2. Polyethylene: Made from ethylene, used for bags and bottles.
  3. Nylon: A polyamide used in various textiles and industrial applications.

Co-Polymer Formation
- Combination of two different monomers releases water (condensation reaction).
- Nylon is highlighted for various uses, including cosmetics such as eyelash-lengthening mascara.

Plastic Notes
  - Australia leads with plastic banknotes.
  - Research Topic:
    - Investigate the pros/cons of plastic vs. paper notes and potential for new designs.

Challenges
- Environmental issues from plastic waste accumulation and finite fossil fuel reserves.
Innovative Solutions
  - Development of bioplastics from plant sugars (e.g., corn, sugarcane)
    - Examples: Polylactic acid (PLA) is compostable, breaking down by microorganisms in weeks.
Advantages and Disadvantages
- Pros: Less energy required for production; can replace conventional plastics in various applications.
- Cons: Extensive land and water use for production, advocating for non-edible plant parts or waste materials.

Graphene Characteristics
  - Discovered by Andre Geim; extremely conductive and strong; composed of hexagonal carbon rings.
  - Potential applications:
    - Energy-efficient light bulbs, water filtration, electronics, biomedical sensors, CO2 removal, and improvements in protective gear.
Commercial Production and Research
- Current commercial products include various innovative applications, notably in health and technology.