First Day

First Day (26 May, Tuesday)
  • What did you do today?
    • We were introduced to the experiment we were going to be doing and did a risk assessment. Today, we did the first experiment which is on the extraction of caffeine from tea. We put green tea leaves of 2g into 8 tea bags. We poured 10g of calcium carbonate into a beaker with boiling water, and left it there for 15 minutes, occasionally stirring the mixture.
    • After that, we filtered the mixture and collected the filtrate. We then poured the filtrate into a separating funnel and added 50 ml of dichloromethane (after measuring) before closing the separating funnel with a cap. We shook the separating funnel 3 times before letting the built-up pressure get released (by opening the tap), and did this step 3 times. We would open the tap to collect the dichloromethane (an organic solvent) with caffeine in it with a flask. Moreover, we had to use a dropper and stir the dichloromethane layer to get rid of the bubbles present. Subsequently, we added 50 ml and 20 ml of dichloromethane and repeated the steps with more dichloromethane.                                              
    • Afterwards, we added magnesium sulphate into the mixture of dichloromethane and caffeine to tell if there was water present in the mixture as we did not want it. We then poured the mixture into a filter with filter paper fitted in, and collected the filtrate in a round-bottomed flask. This round-bottomed flask was attached to a rotary evaporator with a clip, and was spun many times by the evaporator. From there, we collected pure (actually slightly impure) caffeine and scraped it off the wall of the flask.                                                                                       
    • We put one scoop of caffeine onto a mini mortar and added a drop of mineral oil and mixed it around with a pestle provided. We added a drop of the new mixture to 2 pieces of glass and smudged it together. We used the IR scanner to take results in a graph and compared it to the optimum graph our sample should have, it was a little off. We did a report in the form of questions. The end
  • What did you learn today?
    • I learnt that caffeine is good unless taken excessively.
      • Pros
        • Make one alert
        • Reduce drowsiness
      • Cons
        • Can lead to death if 80 cups are consumed in a day
        • Disrupt sleep
        • Cause increased heart rate
      • Tea contains tannin (which makes tea, coffee, beer and other drinks taste bitter), cellulose (presumably from tea leaves) and of course, caffeine.
    • I learnt more about filtration, using different solvents to extract different chemicals from a separation funnel and about new equipment I had not used before.
  • How do you feel about today’s activities?
    • The project has enabled me to deepen my understanding of caffeine and how it is beneficial and harmful at the same time. I have learnt more about chemistry and filtration and about how different chemicals or reagents are added to have different effects on the solution. I have learnt more about the uses of caffeine as well. I can use the knowledge gained to help me in other experiments in the future.
    • It was a great, enriching experience was engaging and entertaining as well. The lab assistants were all very helpful and lent us a helping hand when we needed it.

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