Tea has long been identified as nature's medicine. Its chemical constituents include protein, carbohydrate, lipids, vitamins, minerals, antioxidants and caffeine. Antioxidants in tea are polyphenols called catechins which help preventing cancer formation. Caffeine, however, might cause nervousness, irritability, sleeplessness, etc. Our investigation attempted to identify a "healthy" tea with the highest catechin and lowest caffeine content.
Tea contains tannins in which catechin is an important constituent. As phenol reacts with bromine to form a precipitate 2,4,6-tribromophenol, catechin, a polyphenol, is also susceptible to undergo electrophilic substitution with bromine and precipitates. On the other hand, tannin reacts with lead(II) acetate to form insoluble lead(II) tannate. The amount of precipitate formed in these reactions thus reveals the catechin content in tea. Catechin, also being an antioxidant, reacts with acidified potassium permanganate. The higher the decolorizing power of tea towards permanganate ion, the higher the catechin content in tea.
Caffeine from tea leaves can be extracted with trichloromethane. Before extraction, tannin and lead(II) ions which affect the solubility of caffeine have to be removed. After evaporation of the organic layer, colourless caffeine crystals can be obtained.
We found that teas which contained the greatest amount of catechin were most likely in green tea (綠茶類/青茶類). This coincided with the fact that green tea is unfermented and should contain many undestroyed polyphenols. Our investigation suggested that daffodil (水仙), a green tea, was the "healthiest" tea as it contained the greatest amount of catechin as well as the least caffeine content. Therefore, we strongly recommended at least a cup of daffodil everyday.

18th China Adolescents Science and Technology Innovation Contest
Hazel Cheung and Cynthia Shing of F.7P participated in the 18th China Adolescents Science and Technology Innovation Contest held in Lanzhou, Gansu Province, from 14 to 20 August, 2003. 271 teams of 413 students competed in the contest. Hazel and Cynthia presented their project "Generating Electricity from Pencils and Aluminium Cans" and their booth attracted a multitude of audiences in the Open Exhibition. They attained the 1st Place Grand Award and the Intel Talent Award. They were presented gold medals, ¢D2000 scholarship and certificates.

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Team Members

Karina Ho,

Winnie Sze,

Felice Tsang and

Maggie Yu of F.7A

- Honourable mentions of Hong Kong Student Science Project Competition 2003
- Highly commended award of Hong Kong Chemistry Olympiad for Secondary Schools 2002-2003
- 4th Place Grand Award of the 55th Intel International Science and Engineering Fair in USA (Portland, Oregon) 9 - 15 May 2004

55th Intel International Science and Engineering Fair
Winnie Sze, Felice Tsang and Maggie Yu of F.7A participated in the Intel International Science and Engineering Fair - Hong Kong Regional Competition. They came first in the Team Project Section and represented Hong Kong to participate in the 55th Intel International Science and Engineering Fair held in Portland, Oregon USA, from 9 to 15 May, 2004. The Intel ISEF was the world's largest pre-college science competition and brought together 1429 students from 40 nations. Only the top 27 percent of the projects were granted awards. Winnie, Felice and Maggie presented their project "Environmental Killer - Detergent" in the category of chemistry to the international judges in the interview and the general public in the exhibition respectively. They attained the 4th Place Grand Award and were presented US $500 scholarship and certificates.

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Elaine Yau of F.6A participated in the 5th Iron Man of Science Competition held in 1-2 August, 2003. She was awarded the Mini Iron Man in Round 2 and Round 5 and was presented certificates and plaques.

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Highly commended award of Hong Kong Chemistry Olympiad for Secondary Schools 2003-2004
- Hong Kong Student Science Project Competition 2004
March 2004

56th Intel International Science and Engineering Fair
Anne Tsang of F.7P participated in the Intel International Science and Engineering Fair held in Phoenix, Arizona USA, from 8 to 14 May, 2005. The Intel ISEF was the world's largest pre-college science competition and brought together 1,447 students from 45 countries, territories and regions . Only the top 27 percent of the projects were granted awards. Anne presented her project "Natural Dyes - the Delicious Way" to the international judges in the interview. She attained the 3rd Place Grand Award in the category of chemistry and the American Chemical Society 4th Award. She was presented a total of US $1,100 scholarship, certificates, a T-shirt, a calculator and a subscription to "Chem Matters".

The 19th China Adolescents Science and Technology Invention Contest
Candice Chung, Phoebe Lo and Michelle Sun of F.6P participated in the 19th China Adolescents Science and Technology Invention Contest (第十九屆全國青少年科技創新大賽) organized by the China Association for Science and Technology, The Ministry of Education and The Ministry of Science and Technology from 18 to 24 August, 2004. 343 teams of 494 students competed in the contest. Candice, Phoebe and Michelle presented their project - 'Natural Dyes - the Delicious Way' and their booth attracted a multitude of audiences in the Open Exhibition. They had the chances to demonstrate their abilities in communication in Putonghua and to respond to questions raised by the judges. They attained the 2nd Place Grand Award (優秀項目二等獎) and were presented silver medals and certificates in the contest held in Chengdu, Sichuan Province (四川省成都市).

Hong Kong Student Science Project Competition 2004
March 2004

Hong Kong Student Science Project Competition 2004
March 2004

Hong Kong Jockey Club Science and Technology Invention Competition for Youth (2004-2005) organized by the Hong Kong New Generation Cultural Association and the Hong Kong Jockey Club Charities Trust
Mandy Cheung, Velda Lee and Emily Sin of F.6A presented their project "The Anti-oxidizing Recipe" in the Hong Kong Jockey Club Science and Technology Invention Competition for Youth 2004-05 in the category of Science and Technology Invention Works - science research thesis. They attained 3rd Place Award and were presented $1,500 scholarship, a trophy and certificates.

Hong Kong Chemistry Olympiad for Secondary Schools (2004-2005) organized by the Hong Kong Association for Science and Mathematics Education, Education and Manpower Bureau, Hong Kong Chemical Society and Royal Society of Chemistry
Mandy Cheung, Velda Lee, Emily Sin and Tiffany Tam of F.6A won the 1st Runner-up in the Hong Kong Chemistry Olympiad for Secondary Schools 2004-05 with their project titled "The Anti-oxidizing Recipe" . They were awarded a trophy, silver medals, $500 book coupon and certificates. Mandy Cheung was selected as the best presenter and she received the "Best Presenter" trophy.

20th China Adolescents Science and Technology Invention Contest organized by the China Association for Science and Technology, The Ministry of Education and The Ministry of Science and Technology
Mandy Cheung, Velda Lee and Tiffany Tam of F.6A participated in the 20th China Adolescents Science and Technology Invention Contest held in Beijing, China, from 3 to 9 August, 2005. 336 teams of 504 students competed in the contest. Mandy, Velda and Tiffany presented their project "The Anti-oxidizing Recipe" and their booth attracted a multitude of audiences in the Open Exhibition. They attained the 2nd Place Grand Award and were presented silver medals and certificates.

Hong Kong Jockey Club Science and Technology Invention Competition for Youth (2004-2005) organized by the Hong Kong New Generation Cultural Association and the Hong Kong Jockey Club Charities Trust
Alice Cheung, Penny Ng and Karen Tung of F.6A submitted their project "Essence in Fruit Juices - Vitamin C" to the Hong Kong Jockey Club Science and Technology Invention Competition for Youth 2004-05 in the category of Science and Technology Invention Works - science research thesis. They attained merit and were awarded medals and certificates.

Hong Kong Chemistry Olympiad for Secondary Schools (2004-2005) organized by the Hong Kong Association for Science and Mathematics Education, Education and Manpower Bureau, Hong Kong Chemical Society and Royal Society of Chemistry
Alice Cheung, Iding Chung, Penny Ng and Karen Tung of F.6A presented their project "Stain Devil" in the Hong Kong Chemistry Olympiad for Secondary Schools 2004-05. They attained the highly commended award and were presented certificates and shields. They also obtained the "Most Popular Team" award in the Poster Presentation Session.

21st China Adolescents Science and Technology Invention Contest organized by the China Association for Science and Technology, The Ministry of Education and The Ministry of Science and Technology
Carmen Chung of F.6A, Gillian Lam and Vivian Li of F.6P participated in the 21st China Adolescents Science and Technology Invention Contest held in Macau, from 3 to 7 August, 2006. More than 300 teams of students competed in the contest. Carmen, Gillian and Vivian presented their project - "Green Saviour - Chitin and Chitosan" and their booth attracted a multitude of audiences in the Open Exhibition. They attained the 2nd Place Grand Award and were presented silver medals and certificates.

Hong Kong Jockey Club Science and Technology Invention Contest (2005-06) organized by the Hong Kong New Generation Cultural Association and the Hong Kong Jockey Club Charities Trust
Carmen Chung of F.6A, Gillian Lam and Vivian Li of F.6P presented their project "Green Saviour - Chitin and Chitosan" in the Hong Kong Jockey Club Science and Technology Invention Contest 2005-06 in the category of Science and Technology Invention Works - science research thesis. They attained the 1st Place Award and were presented a trophy and certificates.

Hong Kong Chemistry Olympiad for Secondary Schools (2005-06) organized by the Hong Kong Association for Science and Mathematics Education, Education and Manpower Bureau, Hong Kong Chemical Society and Royal Society of Chemistry
Carmen Chung of F.6A, Gillian Lam, Vivian Li, Jessica Sun and Jenny Szeto of F.6P won the Championship in the Hong Kong Chemistry Olympiad for Secondary Schools 2005-06 with their project titled "Green Saviour - Chitin and Chitosan". They were awarded a trophy, a Chemistry Olympiad bowl (for retention of 1 year), gold medals, $1000 book coupon, certificates and sponsorship to the Chinese National Chemistry Olympiad and Winter Camp 2007 which will be held in Sichuan Province in January 2007. Carmen Chung was selected as the best presenter and she received the "Best Presenter" trophy.

Hong Kong Student Science Project Competition 2006 organized by the Innovation and Technology Commission, The Hong Kong Federation of Youth Groups, Education and Manpower Bureau, and the Hong Kong Science Museum
Carmen Chung of F.6A, Gillian Lam, Vivian Li, Jessica Sun and Jenny Szeto of F.6P attained the Honourable Mention in the Hong Kong Student Science Project Competition 2006 with their project titled "Green Saviour - Chitin and Chitosan". 109 teams of students from 58 secondary schools participated in the competition. They were awarded a trophy and certificates.

Award Program for Future Scientists 2006 organized by the China Association for Science and Technology, Ministry of Education of the People's Republic of China and H.S. Chau Foundation Limited
Gillian Lam of F.7P participated in the Award Program for Future Scientists 2006. She attained the Nomination Award and was presented a certificate and RMB¥1,000 scholarship.

Hong Kong Science and Technology Invention Contest (2006-07) organized by the Hong Kong New Generation Cultural Association Science Innovation Centre, Education and Manpower Bureau and Innovation and Technology Commission
Sonia Kwok of F.6P, Carman Cheung and Fionna Ng of F.6A presented their project "Dyeing hair, Dying hair?" in the Hong Kong Science and Technology Invention Contest 2006-07 in the category of Science and Technology Invention Works - science research thesis. They attained merit and were presented medals and certificates.

Hong Kong Chemistry Olympiad for Secondary Schools (2006-07) organized by the Hong Kong Association for Science and Mathematics Education, Education and Manpower Bureau, Hong Kong Chemical Society and Royal Society of Chemistry
Sonia Kwok of F.6P, Natalie Chan, Carman Cheung, Fionna Ng and Janet Sin of F.6A won the Championship in the Hong Kong Chemistry Olympiad for Secondary Schools 2006-07 with their project titled "Dyeing hair, Dying hair?". They were awarded a trophy, a Chemistry Olympiad bowl (for retention of 1 year), gold medals, $1000 book coupon, certificates and sponsorship to the National Chemistry Olympiad and Winter Camp 2008 which will be held in Jiangsu Province in January 2008. They also attained the "Most Popular Team" award and were presented a shield. Besides, Janet Sin was selected as the best presenter and she received the "Best Presenter" trophy.

20th National Chemistry Olympiad (Finals) and Winter Camp organized by Si Chuan Teacher University, Si Chuan Chemistry and Chemical Engineering Society and Chinese Chemical Society
Sonia Kwok of F.6P, Natalie Chan, Carman Cheung, Fionna Ng and Janet Sin of F.6A participated in the 20th National Chemistry Olympiad (Finals) and Winter Camp held in Chengdu, Sichuan, from 15 to 21 January, 2007. 165 students from 32 different provinces, cities and autonomous regions of China participated in the competition. They attained the 3rd Place Award and were presented Bronze medals and certificates.

Hong Kong Student Science Project Competition 2007 organized by the Innovation and Technology Commission, The Hong Kong Federation of Youth Groups, Education and Manpower Bureau, and the Hong Kong Science Museum
Sonia Kwok of F.6P, Natalie Chan, Carman Cheung, Fionna Ng and Janet Sin of F.6A attained the ¡§Best Booth Presentation Award¡¨ in the Hong Kong Student Science Project Competition 2007 with their project titled "Dyeing hair, Dying hair?". More than 120 teams of students from 66 secondary schools participated in the competition. They were awarded certificates and the Full Year Museum Pass.

22nd China Adolescents Science and Technology Invention Contest organized by the China Association for Science and Technology, The Ministry of Education and The Ministry of Science and Technology
Sonia Kwok of F.6P, Carman Cheung and Fionna Ng of F.6A participated in the 22nd China Adolescents Science and Technology Invention Contest held in Kunming, Yunnan Province, from 30 July to 5 August, 2007. 386 teams of students competed in the contest. Carman, Sonia and Fionna presented their project - "Dyeing hair, Dying hair?" and their booth attracted a multitude of audiences in the Open Exhibition. They attained the 2nd Place Award and were presented silver medals and certificates.

Iron Man of Science Competition 2007 organized by the Faculty of Science, The Chinese University of Hong Kong
Quinnie Chau of F.6A participated in the 9th Iron Man of Science Competition held on 27-28 July, 2007. Eighty Form 6 science students gathered at The Chinese University of Hong Kong to compete in the contest. Quinnie was awarded the Mini Iron Man in Round 2, 3 and 5. She also attained the overall championship in the competition and was presented certificates and trophies.

Hong Kong Science and Technology Invention Contest (2007-08) organized by the Hong Kong New Generation Cultural Association Science Innovation Centre, Education Bureau and Innovation and Technology Commission
Theodora Cheung, Elaine Chow and Shania Tsang of F.6P presented their project "Preservatives in dried food, here for good?" in the Hong Kong Science and Technology Invention Contest 2007-08 in the category of Science and Technology Invention Works - Chemistry and material science. They attained merit and were presented medals and certificates.

Hong Kong Chemistry Olympiad for Secondary Schools (2007-08) organized by the Hong Kong Association for Science and Mathematics Education, Education Bureau, Hong Kong Chemical Society and Royal Society of Chemistry
Theodora Cheung, Elaine Chow, Maggie Lee, Shania Tsang and Cally Wong of F.6P attained the 2nd Runner-up in the Hong Kong Chemistry Olympiad for Secondary Schools 2007-08 with their project titled "Preservatives in dried food, here for good?". They were awarded a trophy, bronze medals, $600 book coupon and certificates. They also attained the "Most Popular Team" award and were presented a shield.

21st National Chemistry Olympiad and Winter Camp organized by Nanjing University, Nanjing Normal University, Jiangsu Province Chemistry and Chemical Engineering Society and Chinese Chemical Society
Theodora Cheung, Elaine Chow, Maggie Lee, Shania Tsang and Cally Wong of F.6P participated in the 21st National Chemistry Olympiad and Winter Camp held in Nanjing, Jiangsu, from 8 to 14 January, 2008. 165 students from 32 different provinces, cities and autonomous regions of China participated in the competition. They attained the 3rd Place Award and were presented Bronze medals and certificates.

Hong Kong Science and Technology Invention Contest (2008-09) organized by the Hong Kong New Generation Cultural Association Science Innovation Centre, Education Bureau and Innovation and Technology Commission
Judy Chung (6A), Joanne Lai (6P) and Janice Wong (6A) presented their project "Shrinkage of Fabric" in the Hong Kong Science and Technology Invention Contest 2008-09 in the category of Science and Technology Invention Works - Chemistry and material science. They attained merit and were presented medals and certificates.

Hong Kong Chemistry Olympiad for Secondary Schools (2008-09) organized by the Hong Kong Association for Science and Mathematics Education, Education Bureau, Hong Kong Chemical Society and Royal Society of Chemistry
Joanne Lai, Kati Lam, Ashley Wong of F.6P together with Judy Chung and Janice Wong of F.6A attained the 1st Runner-up in the Hong Kong Chemistry Olympiad for Secondary Schools 2008-09 with their project titled "Shrinkage of Fabric". They were awarded a trophy, silver medals, $800 book coupon and certificates.

22nd National Chemistry Olympiad and Winter Camp organized by Shaanxi Normal University, Shaanxi Province Chemical Society and Chinese Chemical Society
Joanne Lai, Kati Lam, Ashley Wong of F.6P together with Judy Chung and Janice Wong of F.6A participated in the 22nd National Chemistry Olympiad and Winter Camp held in Xian, Shaanxi, from 5 to 11 January, 2009. 164 students from 32 different provinces, cities and autonomous regions of China participated in the competition. They attained the 3rd Place Award and were presented Bronze medals and certificates.

Iron Man of Science Competition 2009 organized by the Faculty of Science, The Chinese University of Hong Kong
Kati Lam of F.6P and Janice Wong of F.6A participated in the 11th Iron Man of Science Competition held on 24-25 July, 2009. Sixty Form 6 science students from 46 secondary schools gathered at The Chinese University of Hong Kong to compete in the contest. Kati attained the Mini Iron Man award and the best logo design award. She was presented a medal and a certificate.

Australian National Chemistry Quiz organized by the Royal Australian Chemical Institute
Livia Kwan and Irene Kwok of F.7A participated in the 2009 Australian National Chemistry Quiz. Both of them attained a High Distinction Award in the quiz and were ranked top 1% in Hong Kong and top 800 students among 120,000 entries from 1450 schools from 15 countries. They were presented plaques and certificates.

Hong Kong Youth Science and Technology Invention Competition (09-10) organized by the Hong Kong New Generation Cultural Association Science Innovation Centre, Education Bureau and Innovation and Technology Commission
Zoe Chu, Cherry Liu and Cherie Wong of F.6P presented their project 'Iron "Sucks"!' in the Hong Kong Youth Science and Technology Invention Competition (09-10) in the category of Science and Technology Invention Works - Chemistry and material science. They attained 3rd Place Award and were presented a trophy and certificates.

Hong Kong Chemistry Olympiad for Secondary Schools (2009-10) organized by the Hong Kong Association for Science and Mathematics Education, Hong Kong Chemical Society, Royal Society of Chemistry, Hong Kong Education City, Hong Kong Polytechnic University and The Hong Kong Academy for Gifted Education
Zoe Chu, Karen Lau, Cherry Liu, Cherie Wong and Stephanie Yeung of F.6P won the Championship in the Hong Kong Chemistry Olympiad for Secondary Schools 2009-10 - Practical Stream with their project titled 'Iron "Sucks"!' They were awarded a trophy, gold medals, $1000 book coupon and certificates. Zoe Chu was selected as the Best Presenter and she received a trophy and a certificate. In the Non-practical Stream of the competition, Zoe Chu and Eden Boulanger of F.6P attained the Silver Award in the category of Poem and Poster Design respectively. They were presented trophies and certificates.

Hong Kong Student Science Project Competition 2010 organized by the Innovation and Technology Commission, The Hong Kong Federation of Youth Groups, Education Bureau, Hong Kong Science Museum and Hong Kong Science and Technology Parks
The Final Judging cum Award Presentation Ceremony of Hong Kong Student Science Project Competition 2010 was held on 5 June. Zoe Chu, Karen Lau, Cherry Liu, Cherie Wong and Stephanie Yeung of F.6P won the 2nd Runner-up with their project 'Iron "Sucks"!' in the type of 'Investigation of Scientific Phenomena or Application of Scientific Theories' (Senior Division). They received a trophy, certificates and a sponsorship to the World Expo Shanghai 2010 in late July.

International Sustainable World (Energy, Engineering, and Environment) Project Olympiad 2011 organized by the Cosmos Foundation
The fourth I-SWEEEP Olympiad was successfully held in Houston, Texas in United States, from 4 to 9 May, 2011. The science fair brought together 440 top projects from 70 countries and 43 U.S. states to Houston where young researchers presented their innovative projects to take on today's challenges in energy, engineering, and environment. Being one of the Hong Kong delegates, Stephanie Yeung of F.7P presented her project "Iron 'sucks'!" in the contest. She attained the Bronze Award in the category of 'Environment - Senior Secondary Section' and was presented US $400 scholarship, a bronze medal and a certificate.