Chem 131 held a Chemistry Matters Symposium last week during the lab session. We presented about various chemistry related matters or phenomenon in daily life and shared what we learned from the reading. The symposium was much more efficient and entertaining than study all those materials by oneself. Other than learning new stuff in chemistry, I also experienced different types and styles of presentations. My peers’ speeches kind of reflected overall how I did in my presentation. I started to think about how I can improve my presenting skills by listening to others.
Among all the eleven speakers, the top one in my mind belongs to Monica. Her topic was the sweet science of candy making. The first step of making candy is to dissolve the sugar in the water. In a sugar crystal, the sucrose molecules attract each other by intermolecular forces. When the sugar is added into the water, water molecules will bond sucrose molecules and pull them away from each other, so the sugar crystal starts to dissolve. The water, however, can only dissolve a certain amount of sugar and becomes saturated. Actually, at the start of adding sugar into the water, some sucrose molecules also crystallize because they constantly move in the solution, while others are attracted by water molecules. At this time, the speed of dissolving is faster than crystallizing, so it is hard to see any precipitation. As more sugar is added into the water, crystallization speeds up and dissolving slows down, and they finally reach the same speed. This is when saturation happens. If the amount of sugar excesses the saturated point, sugar cannot dissolve into the water anymore, but reaches the dynamic equilibrium with the solution. Water can dissolve more sugar at a high temperature by increasing the dissolving speed. When the water cools down, the sugar crystal forms to generate energy. Thus, rock candy is completed. Monica did a great job explaining the whole process. She walked us through principals clearly and humorously. She talked in a proper volume and speed with gestures. She kept having eye contacts with audiences. She came prepared and spoke fluently. She also did the experiment by herself, so she had a better understanding of how the process worked and what each step looked like. I did not feel that she was nervous. Her way of talking was more like having conversations with friends than giving a speech. I enjoyed listening to her and learned how to make candies.
Another great presentation was about coffee. Coffee is well known for awakening and bringing energy. But how can coffee be so useful? Coffee contains caffeine, the chemical that can alert the brain. After people drink coffee, the caffeine prevents adenosine, which can cause the drowsiness, to get in touch with adenosine receptor. People can stay awake for hours after drinking coffee. Besides alerting the brain, coffee is beneficial to health. Coffee can help people stay away from alcoholism and release stress. Although it is hard to believe, coffee can also protect teeth by preventing the growth bacteria. The deepest impression I had for this speaker was her professional. She wore formal clothes that showed respect to the presentation. Her power point was neat and organized that I could immediately get her outline and emphases. There were only phrases on the slides instead of sentences that I could focus on her talking while also know the main concepts. She pointed to the words on hand so I always followed her thoughts. She spoke calmly and reasonably that made her points easy to understand. The only thing she might improve was to add more pictures to the slides so that people could be more interested in and focused on the topic.
I was also impressed by the talk about chocolate by Lauren. I like her idea to reorganize the contents by her own thoughts and walked us through her reasoning. She divided the most important chemicals in chocolate into two parts, ones that made you feel good and ones that benefited your health. For the first category, chemicals like caffeine and theobromine can make people alert. Other chemicals can stimulate the brain by anandamide to make people feel happy and excited. For the second part, polyphenols, which belongs to antioxidants, is good at preventing Alzheimer’s disease, heart disease, and cancer. Chocolate can prevent the teeth decay as well. However, all these benefits are related to dark chocolates and require a high amount of cocoa. Many chocolates in the markets contain little cocoa and a lot of sugar to improve the taste. Lauren presented with the passion because she loved chocolates. Her passion could influence audiences and engage them more to her topic. She spoke with confidence that her voice was bright and firm. I like the feeling of hearing a story from her talk because she combined the knowledge with our daily lives. She also put some pictures on slides that helped me know the structures of those chemicals.
I like hearing other people presenting. Some people are really good at giving speeches, and I am attracted to them and never feel bored. I can always reflect on myself that if I show the same strengths as others or if I make the same mistakes that make audiences uncomfortable. The most important quality is to be confident and passionate. The speaker’s emotion will deliver to audiences and engage them in the talk. Eye contact is also important and can avoid losing their attention. Most essentially, well prepared before the talk. People can tell if you practice or not. Finally, enjoy the show!