Physics Lab Report Cooling Coffee Essay

Introduction: It is Saturday afternoon. You brew yourself a cup of coffee and are just about to pour cold milk into the coffee. The doorbell rings and you realize immediately that your friend needs your help for a few minutes this afternoon. If you want to have your coffee as warm as possible after you helped your friend, what would be wise to do? Should you pour the milk now, or after you come back? Or does it make no difference? I would like to add the milk into coffee after I come back. Because the hot coffee without milk will cool longer than the warm coffee with milk. Aim: To find out the relationship between the time at which the milk is added, and the final temperature of the coffee/milk mixture. Every minute the coffee was getting cooler (milk was getting warmer until the room temperature), but when we added the milk into coffee it started to cool more faster. Variables: Independent: Dependent: the coffee/ milk temperature dependents of the room temperature. Controlled: To control variables we can change hot coffee/water and milk every minute, or put hot coffee/ water into thermos and milk into object that has same temperature. Hypothesis: My hypothesis is that will be better if we won’t add milk into coffee( because it has a cooling effect), so the coffee will be hoter if we won’t add milk into it. Apparatus: 1. 250 ml beaker 2. 50 ml beaker 3. 100 ml 4. 50 ml measuring cylinder 5. thermometer 6. kettle 7. water cooler 8. stop watch 9. stirring rod Thermometer Diagram: Thermometer Hot Coffee (200 ml) Cold Milk (50 ml) Method: 1) Take 2 test tubes 2) In the first test tube pour milk 3) In the second one pour hot coffee/hot water. 4) Put thermometers into both test tube. 5) Measure the temperature every minute. 6) Record the temperature. Data Collection: At the beginning of the experiment the temperature of the coffee/ hot water was 80.9, but the water started to cool and every minute the temperature was getting lower. 80.9| 79.9| 73.7| 71.7| 65.3| The milk was 19.8 and with every minute it was getting warmer. 19.8| 19.9| 20.1| 20.1| 20.1| So the milk and hot coffee had difference of 61.1 but after mixed together-54.5. Substance:| Temperature(c)as is| Temperature(c)after 1 min| Temperature(c)after 2 min| Temperature(c)After 3 min| Temperature(c)After 4 min| milk| 19.8| 19.9| 20.1| 20.1| 20.1| Hot water| 80.9| 79.9| 73.7| 71.7| 65.3| both mixed together| 53.1| 52.1| 51.0| 51.0| 50.3| Graph: Conclusion and Evaluation: Problems: We used only one metal rod, after hot water we put it into milk ( the rod was hot) and maybe it made a effect to results. Also we use only one thermometer in short time, after hot coffee we measured the temperature of the milk promptly, maybe this can changed results. To solve these problems we should use two metal rods and two thermometers. Make sure you read and follow the checklist!!!!! Design Design| Complete /2| Partial / 1| Not at all /0| Aspect 1 | Define problem and select variables| Formulates a research question and identifies the relevant variables.| Formulates a research question that is incomplete or identifies only some relevant variables.| Does not identify a research question AND does not identify any relevant variables.| Marking Checklist: Research Question (RQ) or Aim clearly stated| | RQ/Aim includes Independent Variable (IV)and Dependent Variable (DV)| | IV correctly identified with units/ range| | DV correctly identified with units| | Prediction is quantitative| | A sketch graph is included, with explanation| | Prediction is explained using scientific theory| | Design| Complete /2| Partial / 1| Not at all /0| Aspect 2 | Controlling variables| Designs a method for the effective control of the variables..| Designs a method that makes some attempt to control the variables.| Designs a method that does not control the variables.| Marking Checklist Method to manipulate IV, including specific details of range or increments| | Method for recording results, including units| | Diagram of equipment or experimental set-up | | Controlled variables presented as a table: * List all variables to be controlledFor each variable: | | How could it impact the results?| | Exactly how will it be controlled?| | Design| Complete /2| Partial / 1| Not at all /0| Aspect 3| Developing a method for the collection of data| Develops a method that allows for the collection of sufficient, relevant data| Develops a method that allows for the collection of insufficient, relevant data| Develops a method that does not allow for any relevant data to be collected| Marking Checklist: How will your results be presented?| | Does your plan address the research question?| | Do you have a minimum of 5 different values for the independent variable?| | Do you have sufficient repeats at each value to ensure reliability?| | Is your method clearly presented and can it be easily followed by others?| | Have you addressed safety?| | Data Collection and Processing DCP| Complete /2| Partial / 1| Not at all /0| Aspect 1| Recording raw data | Records appropriate data including units.| Records appropriate data but with some mistakes or omissions. | Does not record any appropriate raw data OR raw data is incomprehensible.| Marking Checklist: Raw data clearly distinguished from processed data (possibly separate table)| | Units of IV and DV present and correct| | All data are recorded correctly and honestly| | Decimal points consistent throughout| | Decimal points consistent with precision of the measuring equipment| | DCP| Complete /2| Partial / 1| Not at all /0| Aspect 2| Processing raw data | Processes the raw data correctly.| Processes raw data, but with some mistakes and/ or omissions.| No processing of raw data is carried out OR major mistakes are made in processing.| Marking Checklist Calculations to determine DV carried out, if necessary | | Calculations address RQ| | Mathematics correctly applied| | Worked example calculations given| | Processed data (and decimal places) consistent with precision of recorded data| | Data Collection and Processing| Complete /2| Partial / 1| Not at all /0| Aspect 3| Presenting processed data| Presents processed data appropriately| Presents processed data appropriately but with some mistakes or omissions| Presents processed data inappropriately or incomprehensibly| Marking Checklist: Does your graph have an informative title?| | Is it an appropriate size with suitable scales?| | Are the axes labeled with S.I./metric units?| | Are all the points accurately plotted?| | Does it have a suitable line of best fit?| | Conclusion and evaluation CE| Complete /2| Partial / 1| Not at all /0| Aspect 1| Concluding| States a conclusion, with justification, based on a reasonable interpretation of the data| States a conclusion based on a reasonable interpretation of the data| States no conclusion or the conclusion is based on an unreasonable interpretation of the data| Marking Checklist: Have you stated the patterns or trends in your data with reference to your graph?| | Have you offered a scientific explanation of your results?| | Comparisons, if appropriate, are made | | Data related to prediction or RQ – to what extent to they agree/ disagree?| | Appropriate language used â€Å"Supports my prediction† (not ‘proves’ or ‘is correct’)| | Suggestions for further investigation stated| | CE| Complete /2| Partial / 1| Not at all /0| Aspect 2| Evaluating procedures| Evaluates weaknesses and limitations.| Identifies some weaknesses and limitations, but the evaluation is weak or missing.| Identifies irrelevant weaknesses and limitations.| Marking Checklist: Analysis of reliability of results:| | Are data sufficient to address the RQ? | | Was the range of the IV appropriate?| | Identify & Explain anomalous data points| | Refer to data| | Some attempt to evaluate measurement/ instrument errors, systematic error problems with the method) in terms of:| | Possible effect on data| | The validity of the conclusion| | Time management or human error may be mentioned, though these are not scientific errors – they should be eliminated with good practical skills. The focus here should be on the investigation. List your errors and limitations in order; state the most significant error or limitation first! CE| Complete /2| Partial / 1| Not at all /0| Aspect 3| Improving the investigation| Suggests realistic improvements in respect of identified weaknesses and limitations.| Suggests only superficial improvements.| Suggests unrealistic improvements.| Marking Checklist: For each weakness or limitation mentioned above, how could improved experimental design remove or reduce the effect of the error in terms of:| | Techniques used to collect and record data| | Design of the investigation, including range of values chosen and repeats of each IV data point| | Realistic, specific and achievable improvements| |