HONG KONG STUDENT SCIENCE PROJECT COMPETITION 2008

1. HONG KONG STUDENT SCIENCE PROJECT COMPETITION 2008 St. Francis Xavier’s College An investigation on our school team jersey material 濟記球衣の再生

2. Our group members • Chan Tak-wai, Iverson • Chang Siu-kei, Samson • Lui Ka-man, Thomas • So Kwok-ho, Kevin • Yeung Fu-ki, David

3. Investigation background • Many new textile materials are invented • Many schools have chosen new materials for making their sportswear • To investigate if our school have to choose new textile materials

4. Kinds of textile materials • SFXC P.E. uniform (Cotton 1) • PTSS P.E. uniform (Cotton 2) • Low-priced T-shirt (Polyester 1) • Nike Dri-fit (Polyester 2)

5. Investigation method • To examine the performance of 4 kinds of textile materials in - deformation resistance - moisture resistance - water-keeping ability - wicking effect - desiccation ability

6. Experimentdeformation resistance • Good deformation resistance - materials can be used for more times - not easily be broken • Objective - examine the deformation resistance of the materials (with low extending rate, high recovering rate)

7. Experimentdeformation resistance • Procedure -Put a hook of 400g counterweights onto the plastic belt (To test for the extended length) -Take the counterweight off from the belt (To test for the recovered length)

8. Experimentdeformation resistance • Error analysis and improvement • The ruler should measure from the middle of the fabric but not the corner • The ruler should measure the fabric when it is steady

9. Experimentdeformation resistance • Best deformation resistance: Polyester 1

10. Experimentmoisture resistance • Low moisture resistance - Water vapour diffuse away from the body easily • Objective - examine the resistance to vapour diffusion (with great amount of water diffused out)

11. Experimentmoisture resistance • Procedure - Put the fabric into the oven (40℃) ( To dry the fabric completely) - Pour 10g water to the beaker - Mount the beaker mouth with the dry fabric (by a rubber band)

12. Experimentmoisture resistance • Error analysis and improvement • The fabric shouldn’t be touched by bare hand as the sweat will affect the result • The rubber band should hold the fabric tightly (if not, water vapour will diffuse out easily)

13. Experimentmoisture resistance • Lowest moisture resistance: Polyester 2

14. ExperimentWater-keeping ability • Low water-keeping ability - the fabric can hold less water - make the students more comfortable • Objective - examine the ability of holding water during motion (with less water amount held)

15. ExperimentWater-keeping ability • Procedure - Soak the fabric in water till saturation - Dehydrate the fabric by a centrifuge for 2 minutes (to test for the water amount held)

16. ExperimentWater-keeping ability • Error analysis and improvement • The fabric shouldn’t be placed so deep inside the centrifuge tube to prevent the absorption of the removed water • The result should be recorded when the reading on the balance is steady

17. ExperimentWater-keeping ability • Lowest water-keeping ability: Polyester 2

18. ExperimentWicking effect • High wicking ability - The fabric can diffuse liquid water away quickly • Objective - examine the wicking effect (with longer climbing distance of the colored solution)

19. ExperimentWicking effect • Procedure - Put 40mL of colored solution to a beaker - Hang one end of the fabric to a ruler, another end was soak in the solution - Cover the beaker with aluminium foil - Record the result after 10 minutes

20. ExperimentWicking effect • Error analysis and improvement • The mouth of the beaker should be mounted tightly in order to make a close system environment • A beaker should be used instead of test tube (the fabric may touch the inner wall of the test tube)

21. ExperimentWicking effect • Best wicking effect: Polyester 1

22. Experimentdesiccation ability • Good desiccation ability - The fabric can evaporate the water from body quickly • Objective - examine the drying ability (with more water diffused out from the fabric)

23. Experimentdesiccation ability • Procedure - Soak the fabric in water till saturation - Place the fabric with aluminium basin in the oven (30℃) for 20 minutes

24. Experimentdesiccation ability • Error analysis and improvement • The temperature of the oven should be 30℃ to imitate human’s skin temperature • The experiment should be done at the same environment as the humidity will affect the result largely

25. Experimentdesiccation ability • Highest desiccation ability: Polyester 1

26. Conclusion • Best deformation resistance: Polyester 1 • Lowest moisture resistance: Polyester 2 • Lowest water-keeping ability: Polyester 2 • Best wicking effect: Polyester 1 • Highest desiccation ability: Polyester 1

27. Conclusion • We have chosen the textile material- polyester 1 (low-priced T-shirt) instead of polyester 2 (Nike Dri-fit) as our school new sportswear material Because… • Their performance in the tests are similar • But, their price have a big difference Polyester 1: $30 Polyester 2: $120

28. Testing of the new sportswear • Our latest experiment - Wear one of the 2 kinds of sportswear - Stick the filter paper at the back for absorbing sweat - Run for 20 minutes - Measure the mass of sweat absorbed

29. Testing of the new sportswear

30. The endthank you

31. Reference • “Polyester fibers: Chemistry and technology (1971)” by Ludewig Hermann • “Chromatography (1965)” by Savidan, L. • “Cotton (1994)” Woodbridge, Renu Nagrath. • http://www.howstuffworks.com/ • http://www.engr.utk.edu/mse/pages/Textiles/Polyester%20fiber.htm • http://www.engr.utk.edu/mse/pages/Textiles/Cotton%20fibers.htm • http://unesco.uiah.fi/water/material/image06.jpg • http://www.squidoo.com/polyester