Grade Level: 6th to 9th; Type: Physical Science
Gunpowder green tea is made available for sale in a tightly rolled shape and is said to be quite concentrated because of this shape. Most green teas come suspended lose in teabags. The research aspect of this science fair project is to measure two teas using a device called a refractometer to see if there a difference in infusion concentration based on the way the teas are packaged.
- What is a tea infusion?
- How is Loose Rolled Gunpowder tea different from green tea in a teabag?
- Which tea produces a more concentrated brew, loose rolled leaf or tea in a bag?
- Refractometer, which can be purchased at http://www.labexpress.info/salinity-refractometer/
- Distilled water
- Gunpowder green tea pellets
- Chinese green teabags
- Two metric measuring cups
- Two tea cups
- Masking tape
- Two medicine droppers
- Permanent marker
- Label two teacups with the masking tape and permanent marker as follows: “Gunpowder Rolled Green Tea” and “Teabag Loose Green Tea.”
- Open one teabag and pour the contents into the “teabag” labeled cup and the same amount of Gunpowder tea pellets into the corresponding cup.
- Heat water in a teapot or some other vessel until it boils.
- Pour equal amounts of hot water into both teacups and allow both tea brews to cool to room temperature.
- Record the amount of water added.
- Calibrate the refractometer following the directions given by the manufacturer.
- Using a medicine dropper apply 2-3 drops of Gunpowder tea onto the prism surface making sure there are no loose tea leaves in the sample.
- Close cover and point toward any light source.
- Depending on the model refractometer used, focus the eyepiece by turning to the right or left. Locate the point on the graduated scale where the light and dark fields meet. This is the Brix (%) reading for the tea.
- Record the reading in a table similar to the one shown below.
- The refractometer should be rinsed with water and dried with tissue paper after the reading.
- Repeat the same procedure but, this time use green tea that came from the teabag.
- Using a sheet of graph paper or a computer equipped with Excel® visually display the data in the table by plotting a bar graph with the Brix (%) along the vertical axis verse the name of the two teas along the horizontal axis.
Terms/Concepts: Gunpowder green tea, organic green tea, Refractometer, tea infusion, Brix percent calibration, refraction of light; how does the way tea leaves are packaged affect the concentration of the tea infusion?
Reference: Macroscale and Microscale Organic Experiments, Kenneth L. Williamson and Katherine M. Masters, pp. 285-287 (Brooks Cole; 6 edition, 2010).