Investigating the Suitability of the two materials Dri FIT and Cotton in Singapore s Weather Conditions

Transcription

1 LUX STARS, UNITY PRIMARY SCHOOL Investigating the Suitability of the two materials Dri FIT and Cotton in Singapore s Weather Conditions National Weather Study Project 2009 Ang Yu Jia, Low Jing Wen, Low Wei Ning Raelynn, Tammy Wong Ying Qi and Tan Bao Xuan Abstract: In this project, four experiments were carried out to find out if the Dri FIT shirt or the cotton shirt is a better fabric in terms of its absorbency and removal of perspiration and its ability to keep the wearer cool in Singapore s weather conditions. We found out that the cotton shirt can absorb water faster, but the wet Dri FIT shirt dries faster than the wet cotton shirt. Also, the Dri FIT shirt can keep the wearer cooler in gaining heat and losing heat conditions.

2 Content OUR INITIAL PROJECT IDEAS... 2 CREATING A WEATHER WEBSITE... 2 BUILDING AN ENERGY & WATER SAVING MACHINE... 2 OUR FINAL DECISION INVESTIGATING THE TWO MATERIALS... 4 INTRODUCTION... 5 LITERATURE REVIEW... 5 OUR EXPERIMENT FOCUS... 5 METHODS AND MATERIALS... 6 QUESTIONS... 6 HYPOTHESES... 6 EXPERIMENTS... 6 Thermal Property Part Thermal Property Part Absorbency of Perspiration... 7 Removal of Perspiration via Evaporation... 7 RESULTS... 8 THERMAL PROPERTY PART 1 HOW FAST THE FABRICS GAIN HEAT?... 8 THERMAL PROPERTY PART 2 HOW FAST THE FABRICS LOSE HEAT?... 9 ABSORBENCY OF PERSPIRATION REMOVAL OF PERSPIRATION VIA EVAPORATION DISCUSSION CONCLUSION POST PRESENTATION DISCUSSION (WITH JUDGES COMMENTS) ACKNOWLEDGEMENTS LITERATURE CITED APPENDIX I DETAILED DATA FROM EXPERIMENTS APPENDIX II PHOTOGRAPHS TAKEN DURING EXPERIMENTS THERMAL PROPERTY PART THERMAL PROPERTY PART ABSORBENCY OF PERSPIRATION REMOVAL OF PERSPIRATION VIA EVAPORATION Page 1

3 Our Initial Project Ideas Creating a Weather Website Initially, we used the Suggested Weather Project Topics and thought of using the suggestion of building a website. We chose that as we are all very interested in learning more about how to use ICT (Information and Communication Technologies) in our work. Also, some of our group members have just completed a project on setting up of a blog in Young Marine Biologist We thought these skills might be relevant. Figure 1: A Print screen of the PowerPoint Slides, Suggested Weather Project Topics Building an Energy- & Water-Saving Machine Mr Ng, another teacher who had helped us in some ways, gave us the suggestion of building a machine. We loved the idea of building. Last year, we were the same team which took part in Singapore Amazing Machine Competition. The thought of building a machine from scratch sounds really challenging, and yet exciting. Therefore, we brainstormed and came up with a design (please see design on the following page). There were two main objectives for the machines. Firstly, there will be a rain water collection point at the bottom of the machine. Secondly, when running rainwater hit a turbine, it will allow the generator to generate electricity. We wanted this electricity to light up a bulb to indicate the possibility of a lightning on a rainy day. However, after thorough thinking and discussion with our teacher mentor, we decided that the machine may not be feasible for two main reasons. Firstly, our school already has an effective lightning-warning system. Moreover, our idea that a lightning will only occur when it rains is not true. We have observed cases of the lightning-warning system sounded first before the rain pours. Secondly, during the months of our project, it happens to be the North- East Monsoon Season (Climatology of Singapore, 2002). We are expecting a drier period Page 2

4 from February to early March. Therefore, have to change our project topic to something else again. Figure 2: Design of Our Energy and Water Saving Machine Page 3

5 Our Final Decision Investigating the Two Materials Eventually, we took up the idea suggested by our teacher. It was initially a lesson plan that she found from the Internet (Zarske, Forbes, Sirakavit, & Yowell, 2007). The lesson requires students to investigate materials engineering as it applies to weather and clothing. The students will design and analyse different combinations of materials for effectiveness in specific weather conditions. We took up the idea and applied it locally. We realised that nowadays, for some sport jerseys and some other school P.E. attires, the choice is Dri-Fit T-shirt while our school is still using the usual cotton T-shirt. We want to find out if the T-shirt is really better. Our teacher introduced to us the journal-style scientific writing. It was difficult to understand as the articles found online on Google Scholar were usually very detailed and contained a lot of information that we do not understand. We needed our teacher s asistance to explain what the articles were writing about. We made an attempt to write our report in a scientific journal way by using resources online (Anderson, 2004). Although we need our teacher s help in the formatting of the layout of the report, we have learned the scientific process in this project via four main experiments. Ask a question Make a hypothesis Carry out the experiment Check with the hypothesis Make a conclusion Page 4

6 Introduction Literature Review A research (Sazama, 2001) was done to test whether the attires of workers in a paper mill factory will affect their comfort level. In his research, Dri-Fit shirt is referred to vapourpermeable shirt. The results show that the Dri-FIT shirt reduced body core temperatures by about 0.3 to 0.5ºC compared to the cotton shirt. In addition, the Dri-FIT shirt was rated to be more comfortable and to have a faster drying time than the cotton shirt. The data suggests that Dri-FIT shirts allow more skin cooling to take place, thereby reducing the body core temperature. From the earlier research, heat stress was mentioned in the journal. What we understood is that hot condition puts the body under a lot of stress. In Kentucky, heat stroke and heatrelated injuries are quite common among the footballers and high school players (Warren, 2009). In the worst cases, the injuries led to death of the players. Although we seldom hear of heat-related injuries among students in Singapore, we should not ignore the fact that there are people who suffered from heat-related injuries during exercise. The Overview And Recommendations For Sport Safety In Singapore (2007) indicated that there were a total of 822 heat-related injury cases in Singapore Armed Forces from 1995 to Also, based on our personal experience, we feel that it is quite difficult to concentrate during the period after P.E. lesson. The increase in body temperature makes us uncomfortable and restless sometimes. Another research (Kar, Fan, Yu, & Wan, 2007) tested on several properties of fabric on different stages of exercise. It was found that the fabric material with a poorer thermal insulation will make wearer feel warmer at all stages of exercises. In the middle of the exercise when body starts to sweat, clothes with better water vapour transmission property can result in cooler sensation. Lastly, fabric s water absorption and air permeability are important factors after exercise as these properties determine how quickly the skin can be dried after sweating. Our Experiment Focus Our aim is to investigate and find out what is a suitable material for school P.E. T-shirt based on the absorbency and removal of perspiration, and keeping the wearer comfortable in Singapore s weather condition. Therefore, we made use of past research and came up with four different questions, hypotheses and experiments to make one conclusion. Page 5

7 Methods and Materials In all our experiments, we compared our school P.E. T-shirt that is made of mostly cotton (according to the uniform vendor, there is a small percentage of polyester in the fabric) and the prefect s white T-shirt that is made of Dri-FIT material. Dri-FIT is actually a high-tech fabric developed by Nike. Quoted from Nike website, Dri-FIT is a high-tech proprietary fabric developed by Nike which quickly moves sweat to the outer layer of the fabric, away from your skin, where it can quickly evaporate. The result is that you have a dry, cool fabric against your skin even when heat and humidity levels are high. We can confirm that the prefect s white T-shirt is not made from Nike s Dri-FIT, but we do not have the exact content of the fabric. Questions Thermal Property Part 1 How fast the fabrics gain heat? Thermal Property Part 2 How fast the fabrics lose heat? Absorbency of Perspiration How fast the fabrics absorb sweat? Removal of Perspiration via Evaporation How fast the wet fabrics become dry? Hypotheses Based on the past researches, we are told that Dri-FIT material is of a superior quality than normal cotton shirt as it can keep the wearer cooler and it will dry off the sweat faster (Sazama, 2001). Therefore, here are our hypotheses. Dri-FIT shirt gains heat slower than the cotton shirt. Dri-FIT shirt loses heat faster than the cotton shirt. Dri-FIT shirt absorb sweat faster than the cotton shirt. Wet Dri-FIT shirt dries up faster than the wet cotton shirt. Experiments Thermal Property Part 1 Steps: 1. Place three mannequins at the same spot under the sun. 2. Tie the Dri-FIT shirt and the cotton shirts onto the heads of two separate mannequins with the same head-size. 3. Use the third mannequin as a control (no shirt should be covering this mannequin). 4. Set up the data logger. 5. Insert the temperature sensor of the data logger into the covered heads of the mannequin. 6. Set the status of the data logger, e.g. Time to record the data. 7. Press "start" and start recording the temperature change of each set-up. 8. After 30 minutes, save the data in the data logger. 9. The mannequin which has the lower temperature after 30 minutes is covered by the cloth which gains heat slower. Page 6

8 Thermal Property Part 2 The steps for this experiment are mostly the same, except for steps 1 and Place three mannequins on the tables in an air-conditioned room. 9. The mannequin which has the lower temperature after 30 minutes is covered by the cloth which loses heat faster. Absorbency of Perspiration Steps: 1. Cut strips of the same sizes from the two materials (Dri-FIT and Cotton shirt). 2. Prepare two Petri dishes filled with equal amount of water and dye. 3. Put the two cloths close to the Petri dishes, each on one dish. 4. Lay them into the dyed water at the same timing. 5. After two minutes, remove both cloths from the Petri dish. Observe how much water each cloth has absorbed. Measure the length of the water absorbed using a ruler. Compare the amount of water. 6. To ensure accuracy of results, repeat the same experiment for a few times. 7. If the cloth absorbs more water compared to the other, it is more absorbent than the other cloth, and vice versa. Removal of Perspiration via Evaporation Steps: 1. Weigh the two pieces of cloth (1 P.E. T-shirt and 1 Dri-FIT T-shirt) 2. Fill the beaker with 200ml of water 3. Put the pieces of cloth into each beaker each. 4. Wait till all the water is absorb. 5. Weigh the two pieces of cloth. 6. Hang the cloths side by side over the railing for 30 minutes. 7. After 30 minutes, weigh the two pieces of cloth again and find out the difference from the first weight and second weight. 8. Repeat the step 6 and 7 a few more times to get more data. Please look at Appendix II for our pictures taken during experiments. Page 7

9 Results Thermal Property Part 1 How fast the fabrics gain heat? From the graph, it can be seen that in the first 2 minutes (120s), as the slopes of the graphs look similar in steepness, the temperature of the air inside the Dri-FIT shirt is increasing as fast as the temperature of the air inside the cotton shirt. However, after 25 minutes (1500s), the temperature of the air inside the Dri-FIT shirt is lower than the temperature of the air inside the cotton shirt. Look at Table 2 in Appendix I for detailed data. Page 8

10 Thermal Property Part 2 How fast the fabrics lose heat? From the graph, it can be seen that in the first 5 minutes (300s), as the slopes of the cotton graph is steeper than the slope of the Dri-FIT graph, the temperature of the air inside the cotton shirt is decreasing faster the temperature of the air inside the Dri-FIT shirt. However, after 25 minutes (1500s), the temperature of the air inside the Dri-FIT shirt is lower than the temperature of the air inside the cotton shirt. Look at Table 3 in Appendix I for detailed data. Page 9

11 Absorbency of Perspiration Table 1: The absorbency rate of the two shirts in 2 min Trials Length of strips that is wet (cm) Cotton Dri-FIT As the table shown, in all three experiments, the cotton shirt could absorb water faster than the Dri-FIT shirt. Removal of Perspiration via Evaporation The graph shows that the Dri-FIT shirt is drying up faster than the cotton shirt as the slope of the Dri-FIT shirt graph is getting steeper than the cotton shirt graph. Look at Table 4 and 5 Appendix I for detailed data. Page 10

12 Discussion Let us recall the objective of our project. Our aim is to investigate and find out what is a suitable material for school P.E. T-shirt based on the absorbency and removal of perspiration, and keeping the wearer comfortable in Singapore s weather condition. To find out how to make the wearer comfortable, we were trying to look for a material that is gaining heat slowly and losing heat quickly, thus making the wearer cooler. Our data showed that Dri-FIT gained heat slower and lost heat faster than the cotton shirt. At first, we did not understand how these two properties could exist at the same time. In our science lesson, we learn that a material is a good conductor of heat if it gains heat and loses heat quickly, and that a material is a poor conductor of heat if it gains heat and loses heat slowly. How can a material gain heat slowly and yet lose heat quickly? Our teacher pointed out to us that water on the Dri-FIT shirt evaporates very quickly. Since evaporation causes cooling, it quickens the rate which Dri-FIT shirt loses heat. There are three ways which heat is being transferred. They are show in the table below. We have not learnt them in Primary Science, but they could be factors which affect the rate at which Dri-FIT gain and lose heat. Conduction Convection Radiation The transfers of heat in particles of matters with direct contact, e.g. we can feel the heat after some time when we hold a metal rod and heat the other end. The transfer of heat in fluid s motion, e.g. in when a pot of liquid boils even with any stirring. The transfer of heat in vacuum, e.g. heat from the Sun travels through vacuum in space and reach us on Earth. There were many other considerations when we conducted the thermal property experiments. They are as follow:- Since we are only using the head of the mannequins, the body size does not matter The mannequins should not be touching one another The shirts should not be touching the ground The data loggers should only be touching the head of the mannequins During the experiment, do not move the mannequins When we were writing this report, we thought of ways of improving the experiment. We could actually put the mannequins in the Sun for 30 min to simulate 30 min of P.E. lesson and then leave the mannequins indoors to simulate the period after P.E. lesson. However, due to lack of time, we could not carry out the experiments again. We can also get real people to participate by wearing the shirt during PE lesson while we take their temperatures. However, we are not sure if it is possible as it would not be convenient to carry the data sensor while exercising. Page 11

13 Conclusion If we look at the four factors again, absorbency test is the only one that shows that cotton is a better material than Dri-FIT since the cotton strip absorbed water faster than the Dri-FIT strip. However, there are other factors which make Dri-FIT shirt a better choice of P.E. shirt. Dri-FIT shirt gains heat slower and lose heat faster than the cotton shirt and the Dri-FIT shirt also dries faster than the cotton shirt. Therefore, the findings in this project can be used to suggest to our principal that there are good reasons to use Dri-FIT material for our P.E. shirts. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Post-Presentation Discussion (With Judges Comments) After presentation to the judges, we felt that there are a few more things that could be done. We would like to note them down so as to serve as a reference for future teams who would like to explore more on fabric and its application. Firstly, there are other physical properties that can be tested to check for the suitability of shirt materials. Our project only focuses on the following four physical properties: Thermal Property Part 1 How fast the fabrics gain heat Thermal Property Part 2 How fast the fabrics lose heat Absorbency of Perspiration How fast the fabrics absorb sweat Removal of Perspiration via Evaporation How fast the wet fabrics become dry One of the judge suggested that we can also check the durability of the fabric. According to the judge, as a mother, she noted that most white cotton shirt will look old and yellow after several wash. However, Dri-FIT shirt usually continues to look new even after several wash. In school, we are always reminded to put on clean uniforms and shirts, so switching to the use of Dri-FIT may be good choice for school. Another factor that we did not consider is how comfortable the material feels when the wearer puts on the shirt for exercise. A simple survey could be conducted to find out pupils preference. For instance, just in our group, four of us prefer Dri-FIT while one prefers the cotton shirt. Those who prefer Dri-FIT claimed that it feels cooler when they put on Dri-FIT shirt. The pupil who prefers cotton claimed that the cotton shirt could absorb her sweat better and it is unlike Dri-FIT shirt which clings onto her skin when she sweats. We know that this is more of a personal choice. However, a survey would allow us to know what the preference of my schoolmates is in general. Therefore, after our presentation to the judges, we went back to survey our classmates and some prefects. In total, 50 pupils helped us in our survey. All pupils had a chance to look at and feel the material before doing the survey. Here are the two questions and the results. Questions Do you prefer Dri-FIT material as our school P.E. shirt instead of cotton? Do you think it is affordable if our school changes the P.E. shirt to Dri-FIT material? Response YES NO Page 12

14 Here are some responses from our friends when they were asked for the reasons. I think Dri-FIT is warmer than cotton, said Shawn. I respect our (current) school P.E. shirt as our Principal had made the decision for it, said Sarah. Cos cotton is softer, said Zhen Ming. It (Dri-FIT) looks more formal! said May. It (Dri-FIT) is cooler! said May Thu. Last but not least, it is the cost factor. Our principal, Mr Teoh Tiong San, has seen our presentation once. It was during that time that we brought up the suggestion of changing our cotton shirt to Dri-FIT shirt. He told us that he agreed that Dri-FIT shirt is better but he is concerned about the addition cost. Our school is a neighbouring school with about 7.9% of the pupils who are in Financial Assistance Scheme. Increasing the price of our shirts may bring problems to some families who have difficulties buying the shirts. Since cost is a factor, we also went to find out about the additional cost for switching from cotton to Dri-FIT. The shirt vendor told us that each Dri-FIT shirt will cost $2 to $3 more. Since the price of our cotton P.E. shirt is only about $6, $2 to $3 increase is about 33% to 50% increase in price. This is quite a lot for low-income families. As Singaporeans, we all believe that products must be value for money. However, we also realised that so-called Dri-FIT by some vendors is not close to the real Nike s Dri-FIT at all. Some of them are just polyester mixed with cotton, with high percentage in polyester. If that is the case, our increase in spending may not be worthwhile. In conclusion, we learned that there are three other factors that we can look at, beside the four properties which we have tested for. If we want to find out whether a new material is better than the current one, we can also to look at durability, comfort level and cost factor. After considering the additional three factors, we decided that at this moment, we shall stick to the cotton shirt that our school is using. This is because most of our peers come from average-income families. We should choose a material that is more affordable to most families. Also, we personally like the comfort that cotton shirts bring us as it can absorb our sweat. However, the advantages of Dri-FIT are very luring. We have showed that Dri-FIT is better than cotton as it gains heat slower and lose heat faster than the cotton shirt. Wet Dri- FIT shirt also dries faster than the cotton shirt. The only weakness is that Dri-FIT has is that it could not absorb sweat very well. So, considering all advantages of Dri-FIT shirts have over cotton shirts, we should go for it. If in future, our peers parents can spend a few more dollars, we shall then suggest to our Principal to use the Dri-FIT shirts. (But by then, we would not be in school. Our juniors will have to do it for us.) Page 13

15 Acknowledgements We would like to thank the following people for their help given in this project. Ms Yap ST, our teacher mentor. Mr Kelvin Ng, for his advice during the study. Mr Lee, the school OM, for his help in looking for the mannequins. Ms Fatimah, for her donation of the mannequins. Mdm Ros and Ms Ain, for their donation of prefects Dri-FIT shirts. Our school office staffs, for their donation of school s P.E. shirts. School Uniform Vendor, for telling us the content of our school P.E. shirt Our school, for giving us the space and equipment (like Data logger) for our experiments. The Senoko Company for organising this project for us to learn more about climate changes. Page 14

16 Literature Cited Anderson, G. (2004). How to Write A Paper in Scientific Journal Style and Format. Retrieved from Bates College: Climatology of Singapore. (2002). Retrieved from National Environment Agency: Google Scholar. (2009). Retrieved from Google: Kar, F., Fan, J., Yu, W., & Wan, X. (2007). Effects of thermal and moisture transport properties of T shirts on wearer s comfort sensations. Fibers and Polymers, 8 (5), Retrieved from: (2007). Overview And Recommendations For Sport Safety In Singapore. Singapore: Sports Safety Committee. Retrieved from: ile.tmp/sports_safety_committee_26sepo7.pdf Sazama, M. G. (2001). The effect of vapor permeable versus non vapor permeable shirts on heat stress. Thesis PlanB (M.S.) University of Wisconsin Stout. Retrieved from: Warren, J. (10 March, 2009). Player safety bill might be put off until fall. Retrieved from Kentucky.com: Zarske, M. S., Forbes, M., Sirakavit, G., & Yowell, J. (2007). TeachEngineering Free Curriculum for K 12. Retrieved from Integrated Teaching and Learning Program, College of Engineering, University of Colorado: b_/activities/cub_weather/cub_weather_lesson01_activity1.xml Page 15

17 Appendix I Detailed data from experiments Table 2: How fast the fabric gain heat? Temperature ( C) Time (s) Cotton Shirt Control Dri FIT Shirt Page 16

18 Table 3: How fast the fabric lose heat? Temperature ( C) Time (s) Cotton Shirt Control Dri FIT Shirt Page 17

19 Table 4: Mass of the shirts before they were wet Mass (g) Cotton shirt Dri-FIT shirt Table 5: Mass of the wet shirts over two hours Time (min) Mass (g) Cotton shirt Dri-FIT shirt Page 18

20 Appendix II Photographs taken during experiments Figure 3: The two shirts in our investigation Figure 4: Initially, we used recycled bottles, instead of the mannequins, to hold the cloth,. Page 19

21 Figure 5: Hardworking girls trying to understand the article Figure 6: This is what we read! Page 20

22 Thermal Property Part 1 Figure 7: Putting on the shirt on the mannequin's head for the experiment Figure 8: Getting the data logger ready Page 21

23 Figure 9: Inserting the sensor inside the 'clothing'. Figure 10: Gaining heat... Page 22

24 Thermal Property Part 2 Figure 11: The mannequins and us in the NE room Figure 12: The data logger Page 23

25 Figure 13: Putting on the cloths for the mannequins Figure 14: The 3 musketeers! Oops? It s mannequins! Page 24

26 Absorbency of Perspiration Figure 15: We are making sure that the correct amount of water is being poured into the cylinder; 'eye level' Figure 16: Before and after some dye was being dripped into each Petri dish filled with water. Page 25

27 Figure 17: Cutting the shirt into strips Figure 18: Making sure that the both cloth are starting at the same point Page 26

28 Figure 19: Dyed water being poured into the Petri dishes Figure 20: The two cloths absorbing the dyed water Page 27

29 Figure 21: Time to measure the length of water absorbed! Figure 22: Pupils washing the apparatus after the experiment Page 28

30 Removal of Perspiration via Evaporation Figure 23: Apparatus needed for evaporation experiment Figure 24: Weighing the shirt several times and then take the average mass Page 29

31 Figure 25: Let's wet the shirt! Figure 26: Do our best to make the shirt absorb every drop of water Page 30

32 Figure 27: Hanging our shirts to dry Figure 28: Our warning sign for others to keep out Page 31

33 Figure 29: Take average mass of the wetted shirts Figure 30: Take the mass of the shirts every 30 min Page 32