2. Methods

  • Tannic acid (1g)
  • Beverages: Yellow Label Tea, Jasmine Tea, Ti-Kuan Yin Tea, Green Tea, Earl Grey Tea, Blueberry Black Tea, Lemon and Lime Twist Green Tea (2 tea bags each)
  • Distilled water (50 ml)
  • Graduated cylinder or metric measuring cup (10 ml) x3
  • Test tube x7
  • Beaker (1000 ml) x1
  • Rubbing alcohol (1 ml)
  • Masking tape x1
  • Medicine dropper  x1
  • Permanent marker x1
  • Boiling Plate x1
  • Beaker (100ml)  x7
  • Glass Rod x1

  1. Label 7 test tubes with the masking tape and permanent marker as Yellow Label tea, Green Tea, Blueberry Black Tea, Lemon and Lime Twist Green Tea, Ti Kuan Yin, Earl Grey, Jasmine Tea
  2. Boil 700 ml of  water in a 1000 ml beaker.
  3. Measure 1 gram of tannic acid.
  4. Pour 1 cm3 of rubbing alcohol into the tannic acid.
  5. Dilute it with 50ml of distilled water
  6. Mixed the solution with the glass rod.
Fig.1 Tannic Acid Solution
  1. Pour 50 ml of boiled water into each beaker.
  2. Put 2 Tea bags in each beaker and let it rest for 4 minutes.
  3. Take out the tea bag and pour 3 ml of tea into the measuring cylinder.
  4. Pour the tea into a test-tube.
  5. Drop the tannic acid solution using a medicine dropper.
Fig.2 Dropping Tannic Acid
  1. Record the number of drops added until white precipitation is formed.
  2. Repeat steps 6 to 12 for another 2 times to find out the average number of drops for a more accurate result.

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