School of Science and Technology
Investigations Science Skills
Rachel Tan (7), Gloria Ng (6), Ling Si Hui (5)
Group Reference: G
1. Indicate the type of research that you are adopting:
[ ] Test a hypothesis: Hypothesis-driven research
e.g. Investigation of the antibacterial effect of chrysanthemum
[ ✓ ] Measure a value: Experimental research (I)
e.g. Determination of the mass of Jupiter using planetary photography
[ ] Measure a function or relationship: Experimental research (II)
e.g. Investigation of the effect of temperature on the growth of crystals
[ ] Construct a model: Theoretical sciences and applied mathematics
e.g. Modeling of the cooling curve of naphthalene
[ ] Observational and exploratory research
e.g. Investigation of the soil quality in School of Science and Technology, Singapore
[ ] Improve a product or process: Industrial and applied research
e.g. Development of a SMART and GREEN energy system for households
2. Write a research proposal of your interested topic in the following format:
Research Title: An Investigation on the Amount of Caffeine in Different Teas.
Research Question: Which type of tea have the most amount of caffeine?
A. Question or Problem being addressed
Most tea are known for keeping people awake but do you know that caffeine is the one which causes this effect? Caffeine is a bitter, white crystalline xanthine alkaloid and a stimulant drug. In the human body, it acts as a stimulant to the central nervous system, which would temporarily ward off drowsiness and restore alertness. It is the world’s most widely consumed psychoactive drug but unlike other psychoactive drug, it is legal and unregulated in most parts of the world. Some beverages that contain caffeine are coffee, tea, soft drinks and energy drinks. This is why people people who work for really long hours needs to have caffeine to boost them up. But, people start to overuse caffeine, taking more and more caffeine to keep themselves awake. However many do not know the harmful effects that it causes such as insomnia, nervousness, restlessness, irritability, stomach upset, irregular or fast heartbeat and muscle tremors.
Some people are quite concern about this factor, therefore some companies has already stated this compound in their nutrition facts. However, not all companies does this thus we want to give people more insight of how much caffeine can be found in these drinks. Through our research, we hope to find out how much of caffeine content are actually in some of the selected teas.
B. Goals/ Expected Outcomes/ Hypothesis
We aim to find out the amount of caffeine in the selected teas and determine which type of teas have the highest and lowest amount of caffeine. We hope that our data collected and conclusion will give people a better insight on their own consumption of caffeine and their health.
After comparing and analysing our data, we are hoping to find the tea that has the ideal amount of caffeine in which our bodies can consume. We expect the conclusions that we make are supported by other previously-completed research papers.
- The different types teas used to test for caffeine
- The amount of caffeine in the different teas
- The amount of tea used to test for caffeine
- The amount of time taken to boil the tea bags
- The number of tea bags used
Based on these variables, we have created the hypotheses for our experiments:
If we use Earl Grey Tea, the amount of caffeine attain will be the highest.
C. Description in detail of method or procedures
- 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
- 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
- Measure 1 gram of tannic acid.
- Pour 1 cm3 of rubbing alcohol into the tannic acid.
- Dilute it with 50ml of distilled water
- Mixed the solution with the glass rod.
Fig.1 Tannic Acid Solution
- Boil 400 ml of water in a 1000 ml beaker.
- Pour 50 ml of boiled water into each beaker.
- Put 2 Tea bags in each beaker and let it rest for 4 minutes.
- Take out the tea bag and pour 3 ml of tea into the measuring cylinder.
- Pour the tea into a test-tube.
- Drop the tannic acid solution using a medicine dropper.
Fig.2 Dropping Tannic Acid
- Record the number of drops added until white precipitation is formed.
- Repeat steps 6 to 12 for another 2 times to find out the average number of drops for a more accurate result.
Risk and Safety: Identify any potential risks and safety precautions to be taken.
1. The experiments involve heating and thus, wear goggles when boiling.
2. As this experiment involve heating, use thongs when handling these liquid. Do not use your bare hands to touch the boiling substance as it may burn you.
3. Be cautious when handling tannic acid. There are many different side effects of tannic acid like stomach irritation, nausea, vomiting, and even liver damage if not used properly. Ensure that it is not consumed.
4. Turn off the bunsen burner when not in use to prevent a fire from breaking out.
1. Measure the number of drops of tannic acid added into the teas and calculate the average number.
2. From the table, draw a bar graph with the number of drops of tannic acid added to the teas.
3. The one with the least amount of tannic acid added is the tea which has the most amount of caffeine.
Bersten, I. (1999). Coffee, “Sex & Health: A History of anti-coffee crusaders and sexual hysteria.” Sydney: Helian Books Retrieved on July 12, 2014 from http://en.wikipedia.org/wiki/Caffeine
Calhoun, M. (n.d.). “Which Decaffeinated Tea Type Contains the Least Amount of Caffeine?” Retrieved on July 16, 2014 from http://www.education.com/science-fair/article/decaffeinated-tea-least-amount-caffeine/
Hartney, E. (2014). “Amount of Caffeine in Foods and Drinks.” Retrieved on July 13, 2014 from http://addictions.about.com/od/Caffeine/tp/Amount-Of-Caffeine-In-Foods-And-Drinks.htm
Klein, S. (n.d.) “12 Surprising Sources of Caffeine” Health Magazine” Retrieved on July 10, 2014 from http://www.health.com/health/gallery/0,,20313656,00.html
Pendergrast, M. (2001). “Uncommon Grounds: The History of Coffee and How It Transformed Our World.” London: Texere. Retrieved on July 8, 2014 from http://en.wikipedia.org/wiki/Caffeine
Steel, M. (2010). “A Laboratory Manual of Organic Chemistry for Medical Students(pg 143-144)” Retrieved on July 14, 2014 from http://www.education.com/science-fair/article/decaffeinated-tea-least-amount-caffeine/
Tran, L. (12 March 2014) “14 Surprising Facts About Caffeine, Explained by Science” Retrieved on July 12, 2014 from http://mic.com/articles/84925/14-surprising-facts-about-caffeine-explained-by-science