COOLING COFFEE THE RELATIONSHIP BETWEEN DIFFERENT BRANDS OF DISPOSABLE CUPS AND HEAT LOSS

Transcription

1 2 0 1 S C I E N T I F I C L O G B O O K Y E A R 9 COOLING COFFEE THE RELATIONSHIP BETWEEN DIFFERENT BRANDS OF DISPOSABLE CUPS AND HEAT LOSS S T U D E N T R E S E A R C H P R O J E C T

2 Date 1/2/1 2/2/1 4/2/1 5/2/1 /2/1 7/2/1 Action Our class was told that we had to do a student research project this term, and was asked to brainstorm ideas for it. I m not entirely sure what I want to do. Our proposal is due on the 10/2/ I browsed past projects on the Young Scientist website as well as other sites from the internet including sciencebuddies.com. I decided that I wanted to do a project involving people and their ability to multitask since it is a relevant topic in society today. Perhaps: - The effect of different types of music on memory - The effects of different distractions on memory - The effect of texting while walking I m going to brainstorm more ideas and write the proposal over the weekend Just notified that a project involving human subjects is not recommended and that our class isn t allowed to do it. Apparently, we would require a range of test subjects (and a lot of them) to ensure accurate results. I was very disappointed and now am really stuck on ideas. I continued browsing the web for ideas for my research project. Some that interest me are: - The effectiveness of different hand sanitisers - The insulation of different coffee cups - The absorption of different brands of cat litter I m really keen on the first idea, however, I m unable to obtain the equipment required (petri dishes and agar) in order for it to work. If I ordered the supplies online, it would take approximately 2 weeks for it to be delivered. I ve decided to base my research project on the insulation of different coffee cups since coffee plays an important role in many people s lives (especially my parents). From personal experiences, I know that different coffee cups do have different insulation qualities. For example, despite ordering it at the same time, two of my friends came back with coffee with different tempers. It might have had something to do with the making of the coffee. However, it s likely that the cup had an effect on this. One cup was from a small cafe, the other was from Gloria Jeans. I ve got my variables written down. I m going to plan and write a rough method for my proposal tomorrow Aim To compare the effectiveness of different brands of disposable coffee cups as an insulator for hot liquids What is the independent variable and how are you varying it? The insulator used - varied by testing different types of cups What is the dependent variable, how are you measuring this variable and what units will be applicable? The heat loss after a certain time - measured by recording the temper of the water at 5- minute intervals for 30 minutes, and then subtracting the final temper from the initial temper to determine the overall temper change. What are the controlled variables in this experiment? How will you control them? The controlled variables in this experiment include - the time and location in which the experiment takes place in (each set of cups will be tested at the same time in the same non-airconditioned room to ensure that the conditions are fair) - the volume of hot water poured into each cup (200mL) - the presence or absence of a lid (the lid which comes with the cup will be used) - the size of the cups used (8oz) I ve completed my proposal. From prior knowledge and preliminary reading on the topic, I ve hypothesised that the design of various brands of coffee cups affects the heat insulation qualities of the cup since some designs will minimise the transfer of heat energy more effectively. My prediction is that after a certain time, the water in the generic styrofoam cup will have the least overall temper change

3 EQUIPMENT REQUIRED: Different types of coffee cups (8oz) with lids (tba) Measuring cylinder (or alternate measuring equipment) Hot water (kettle + tap water) Thermometer Stopwatch (phone) Permanent marker (to label cups) Pen (to create a hole on the lids for the thermometer) RISK ASSESSMENT Hazard Risk Likelihood Control Management Hot water - Container containing hot water can be accidentally knocked over - Contact with extremely hot liquids can result in burns Possible - Be aware of surrounding environment - Take extreme care when moving hot water between containers (ie. between the beaker and coffee cup) Spills - May cause people to slip/trip Possible - Don t place cups too close to the edge of the table - Mop up spills as soon as it occurs METHOD (V1): 1. Label each coffee cup of the same type with a different number between 1 and 5 as shown below 1. Gather all cups labelled with the number 1 and arrange them in a line 2. Using a pen, place a hole in the top of the lid of the coffee cup, ensuring that the thermometer can fit snugly. 3. With a kettle, heat 00mL of tap water to 9 C* 4. Measure 100mL of hot water using the measuring cylinder 5. Fill each cup with hot water.. Quickly place the lid onto the cup. 7. Record the initial temper of the water with a thermometer. 8. Record the temper of the water at 5 minute intervals for 30 minutes. 9. Repeat steps 2-9 four more times with a new set of cup (ie. labelled with the number 2, then 3 etc) *Note: The initial temper of the water is slightly difficult to control, therefore I have designed the experiment so that it will not affect the final result by using the overall temper change. However, all water will start at or very close to 9 C. I haven t finalised what brand of coffee cups I m going to use yet, as I m not sure which companies would be willing to give me cups to test. However, the cups I have in mind are: Styrofoam (already have at home), McDonalds (asking a friend who works there), Gloria Jeans (city), Starbucks (city), The Coffee Club (city) Expresso Cafe (local) 10/2/ While waiting for my proposal to be approved, I decided to conduct preliminary trials to test if it is appropriate to leave coffee cups to cool for 30 minutes (ie. is 30 minutes long enough for coffee to cool, too long, or just right?)

4 Since the styrofoam cup will take the longest to cool, I will record the temper change of the water in the styrofoam cup for 30 minutes to observe the temper loss. Type of Cup Initial after 5 after 10 after 15 after 20 after 25 after 30 Final Change Styrof oam 1 Styrof oam 2 Styrof oam I noticed that in the first trial, the water temper decreased faster in the first 15 minutes than the last 15 minutes of the experiment. I wasn t sure if it was an error in the experiment (perhaps the lid wasn t put on properly at first) so I repeated the experiment to make sure. While doing the second trial, I attempted to multitask and didn t keep watch on the time, which is why there is missing data. While doing the actual experiment, I ll ensure that I ve set a timer for every 5 minutes rather than just relying on the stopwatch. Here is a modified list of equipments and the modified method EQUIPMENT REQUIRED (V2): Different types of coffee cups (8oz) with lids (tba) Beaker Hot water (kettle + tap water) Thermometer Stopwatch Permanent marker (to label cups) METHOD (V2): 1. Label each coffee cup of the same type with a different number between 1 and 5 as shown below 2. Gather all cups labelled with the number 1 and arrange them in a line 3. With a kettle, heat 1000mL of tap water to 5 C 4. Measure 200mL of hot water using a beaker 5. Fill each cup with hot water.. Quickly place the lid onto the cup. 7. Record the initial temper of the water with a thermometer. 8. Record the temper of the water at 5 minute intervals for 30 minutes. 9. Repeat steps 2-9 four more times with a new set of cup (ie. labelled with the number 2, then 3 etc) CHANGES: - Step which involves creating a hole on the top of the lid has been omitted since I could only find a digital laser thermometer to use in the experiment mL only filled half a coffee cup, so I changed the volume of water to 200mL per cup

5 - As a result, I require a total of 1000mL of water for 5 cups (instead of 00mL for cups as originally planned) - I couldn t find a measuring cylinder, so I replaced it with a beaker. I only have a 100mL beaker - The initial temper is to be 5 C instead of 9 C which is found to be too hot 11/2/ I ve designed my results tables! Change after 30 minutes Type of Cup 1st Trial 2nd Trial 3rd Trial 4th Trial 5th Trial Average Styrofoam NthTrial Type of Cup Initial after 5 after 10 after 15 after 20 after 25 after 30 Final Change Styrof oam /2/ My proposal had just been approved! I m going to start collecting the equipment required for the experiment. Here are some concepts that need to be researched for my introduction: - What is heat energy? - What is insulation? - How is heat transferred? (in particular, how is it transferred in coffee cups) - What is conduction? - What is convection? - What is radiation? I ve also asked my friend to try to get me cups and lids from McDonald s

6 14/2/ 20/2/ 24/2/ 25/2/ 28/2/ My friend informed me that she was unable to get cups and lids from McDonald s as her manager doesn t let her. I tried asking another friend who works at a different branch, since different stores have different policies I planned to travel to the city to gather cups from various stores. Unfortunately, I ve been sick and haven t worked on my project much. Fortunately, my other friend was able to get cups and lids from McDonald s and will be giving them to me as soon as I get back to school... I was able to get 5 cups from the Gloria Jeans at Olympic Park. However, they weren t willing to give me lids. Gloria Jeans did not charge me anything for the cups. I was able to get lids from another Gloria Jeans in the area! I ve started the some of the research required for my experiment, and thus started writing my introduction. Here s a summary of the information I ve gathered and their sources I ve got camp next week and won t be able to work on my research project again... What is heat energy? - All matter is made of molecules and atoms (Caltech, 20) - They re always in motion, which creates heat or thermal energy How is heat transferred? - Transferred from one place to another by one or a combination of conduction, convection and radiation - Conduction and convection involves particles, while radiation involves electromagnetic waves /2/ I added more information on heat transfer by conduction and convection. I ve got camp for the rest of this week and won t be able to work on my experiment. Conduction - An example is when heat energy is conducted from the hot end of a rod to the cold end (BBC, 2015) - Atoms or molecules in solids don t have the freedom to move, as liquids or gases do, so the energy is stored in the vibration of atoms. An atom or molecule with more energy transfers energy to an adjacent atom or molecule by physical contact or collision (PSU, 2015) - For example, the valence electrons in a piece of metal or delocalised, meaning they can leave their atoms, and move about in the metal structure. The parts of the metal atoms left behind are now charged metal ions. The ions are packed closely together and they vibrate continually. The hotter the metal, the more kinetic energy these vibrations have. This kinetic energy is transferred from hot parts of the metals to cooler parts by the delocalised electrons. These move through the structure of the metal, colliding with ions as they go (BBC, 2015) - Solids transfer thermal energy through convection most efficiently since the molecules in solids are most tightly packed (study.com, 20) - An atom or molecule with more energy transfers energy to an adjacent atom or molecule by physical contact (PSU, 2015) - Some materials are better at reducing conduction effects than others.

7 - Heat loss via conduction is when the heat in liquids in the cup are transferred to outside via the walls of the cups - Heat flows from warmer to cooler objects until they re both the same temper (Caltech, 20) Convection - Convection is when the gas or liquid itself moves (PSU, 2015) - Most efficient way to transfer heat generally (Caltech, 20) - Warm air rises because it s less dense (BBC, 2015) - Particles with more thermal energy vibrate faster, and are further apart - Atoms or molecules with more heat energy take place of particles with less heat energy /3/1 I was also able to get cups and lids from Donut King and Muffin Break. They charged me 50c/cup and $1/cup respectively. Thanks mum for driving me and for paying for this! I ve also done additional research on the radiation and thermal insulation. Radiation - Third method of transfer is radiation, which does not rely upon any contact between the heat source and the heated object - For example, heat from the sun - Energy is carried by electromagnetic waves - Shinier, lighter colours are better at reflecting infrared radiation What is insulation? - Thermal insulation is a general term used to describe products that reduce heat loss or heat gain by providing a barrier between areas that are significantly different in temper (thinkinsulation, 2012) - Thermal insulation is the reduction of the transfer of heat transfer between objects in thermal contact or in range of radiative influence. - the reduction of the transfer of thermal energy between objects in thermal contact, Thermal insulation /3/1 I ve decided to start my experiment. However, since each trial takes 30 minutes, I only have time to do one today due to other commitments. 1st Trial Type Initial Final

8 of Cup after 5 after 10 after 15 after 20 after 25 after 30 Change Styrofo am McDon alds Gloria Jeans Donut King Muffin Break /3/1 I did another two of my trials 2nd Trial Type of Cup Initial after 5 after 10 after 15 after 20 after 25 after 30 Final Change Styrofo am McDon alds Gloria Jeans Donut King Muffin Break rd Trial Type of Cup Initial after 5 after 10 after 15 after 20 after 25 after 30 Final Change

9 Styrofo am McDon alds Gloria Jeans Donut King Muffin Break /3/ I managed to complete my final two trials and graphed the results using the averages 4th Trial Type of Cup Initial after 5 after 10 after 15 after 20 after 25 after 30 Final Change Styrofo am McDon alds Gloria Jeans Donut King Muffin Break th Trial Type of Cup Initial after 5 after 10 after 15 after 20 after 25 after 30 Final Change Styrofo

10 am McDon alds Gloria Jeans Donut King Muffin Break Type of Cup 1st Trial 2nd Trial Change after 30 minutes 3rd Trial 4th Trial 5th Trial Average Styrofoam McDonalds Gloria Jeans Donut King Muffin Break

11 The results showed that the styrofoam cups were consistently the most effective insulator out of the disposable coffee cups tested because it has the least amount of heat loss overtime. They were followed by Gloria Jeans and Donut King cups. Muffin Break and McDonald's coffee cups were the least effective insulators. I was a bit concerned about the accuracy of the experiment. To improve the accuracy of the experiment, I measured the temper of the water every 5 minutes to ensure that there was not a sudden, unexplained change in temper. However, the issue was that when measuring the temper of the water with the digital thermometer, I had to take off the lid for a certain time. There was an attempt to keep the time in which the lid was off the cup consistent throughout all the trials, however, this would still have somewhat of an impact. With this experiment, customers can decide which store gives them the hottest coffee. Also, different manufacturers can use this information to design the perfect coffee cup. I am happy with the work I put into this experiment, and have discovered interesting information about different brands of coffee cups. For example, I thought muffin break would have had the best coffee cup (after styrofoam) because they charged me $1 per cup! 13/3/ I ve hypothesised that the design of the cups would influence the insulation qualities, and my results supported this hypothesis as styrofoam was the best insulator out of the cups tested. I did some further research on styrofoam, and found that although they re effective, most companies don t use them because they aren t environmentally friendly Styrofoam cups are the most effective insulator They are 95% air, allowing it to trap warm air. The trapped air inside the styrofoam prevents heat from effectively passing out of the cup by limiting conduction effects. Styrofoam is structured as microscopic air bubbles contained by relatively stiff walls. In addition to making the substance lighter, the bubbles reduce the material s thermal conductivity to a value only slightly higher than that of air. However, styrofoam cups are not eco-friendly

12 Non-biodegradable = made from polystyrene - a petroleum-based plastic Styrofoam is lightweight, and therefore floats. Polystyrene has accumulated along coasts and water ways around the world Petroleum is a non-sustainable resource I was curious as to how the other cups were made, so I cut it up to find that they were made from practically the same thing - a double layer of paper. So why were there such difference between their results? Then, I realised that of course, there had to be other factors affecting the insulation quality! These are some ideas that could be further investigated. For example, perhaps the colour of the cup had some sort of effect on the insulation qualities, since lighter colours reflect radiation better. However, I think the most important factor was the diameter of the top of the cup, since researched had shown that convection was the most efficient in transferring thermal energy. Although all cups have the same volume and capacity (8oz), they re shaped differently. The size of the top is directly proportional to heat loss Type of Cup Diameter of Cup (cm) Average Change Styrofoam McDonald s 8. Gloria Jeans Donut King Muffin Break /3/ I thought I was cutting it a little bit close because my draft report is due in 2 days. I had to form sentences from my research on heat for my introduction, and also to write my discussion. Since I already had all the information required, it didn t take too long and I managed to finish the entire report today. It was merely a matter of wording information and copying and pasting the method/equipment list. Thanks to the school for providing me with this template!

13 17/3/ 19/3/ 21/3/ 25/5/ 01// I ve submitted my draft report! I researched further and learnt that paper cups are not entirely recyclable since they are often lined with polyethylene (plastic) or wax to prevent liquids from leaking out or soaking through the paper. This lining is too difficult to separate during the paper recycling process. I got my friend to peer review my report, and she suggested not to have any first person pronouns. I ve reworded parts of my introduction and my discussion. My final report is due in 2 days :) I thought that the journey was over for this project but it turns out, it s not. I ve been invited to participate in a science conference at school where a panel of external judges come, and listen to our presentations and judge, asking questions regarding my experiment. I ve got approximately a week to refine my SRP with the feedback received from my class teacher. There was an information session held at lunch yesterday. The teacher suggested we investigate measures of spread in our discussion, and improve the analysis of our results. So I calculated: The gradient of the lines in the line graph to show the rate in which the temper is decreasing. The steeper the slope, the greater the temper change over 30 minutes, and the worst of an insulator they are. The cups with a gentler slope, like styrofoam, are better insulators. Perhaps the difference isn't really that significant. The difference in gradient between the worst and best cup is However, in saying that, there is still consistently a slight difference in temper between each type of cup. Styrofoam m = (2dp) McDonald s m = (2dp) Gloria Jeans m = (2dp) Donut King m = (2dp) Muffin Break m = (2dp) The r squared value which showed that there was a strong positive correlation between the diameter of the cup and the temper change of the liquid in the cup over time. r² = (with styrofoam) r² = (without styrofoam) 10// Last night, I presented my student research project to a panel of external judges and was a finalist! They asked question and provided insight into other ways I could take my project a step further: - How would the shape of the cup affect the temper change, while providing the same amount of coffee (turns out sphere was the best shape, but it s impractical) - Would there be a difference if coffee was used instead of water - Would the graph still be linear if we extended the duration of the experiment 0/08 / I ve refined my report, adding in feedback from the judges and my teachers. I also added in the standard deviation for each type of cup across the five trials, to measure the reliability of the experiment

14 Type of Cup Change after 30 minutes 1st Trial 2nd Trial 3rd Trial 4th Trial 5th Trial Average Standard Deviation σx Styrofoam (2dp) McDonald s (2dp) Gloria Jeans (2dp) Donut King (2dp) Muffin Break (2dp) I will be submitting my report, along with this logbook to the Young Scientist Competition!