Paul heat


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Paul heat

  1. 1. Paul Laohapiengsak Geoscience Ms. Perkins Period 2 Heat Transfer Introduction: Energy refers to “the capacity of a physical system to do work”. Nowadays, energy plays a vital role in humans’ lives. It provides mankind with a convenience life style ranging from transportation to many electronic devices. According to the law of conservation of energy, “Energy can never be created or destroyed, only transformed from one form to another”. Nevertheless, energy transfer can result in heat. Furthermore, energy can also be in various forms such as kinetic, potential, sound, gravitational, and elastic energy. There are mainly two forms of energy, which are renewable and renewable source of energy. The examples of renewable energy source are wind and water while the nonrenewable sources of energy arecoals and gasoline. Although energy are extremely beneficial to human beings, nevertheless some sources of energy when consumed can result in many negative impacts to the environment such as burning coals will create air pollution. For this reason, human beings should consider not only preserving energy but also beware of the negative impacts it will cause upon nature. The purpose of this lab is to measure rate of heat transfer. In this investigation, many objects will be used as containers of heat energy, in this case “hot water”, which are metal, foam, paper, and Styrofoam. The temperature of each container will be recorded carefully base on the amount of time it takes for the temperature of the objects to decrease. The starting temperature of a 50 milliliters hot water will be 60° Celsius. As metal has the property of faster heat transfer, it is predicted that, it will cool down faster than the other objects. For this reason, it is predicted that objects that is a heat conductor will have a high rate of heat transfer. Research Question: What type of container has the capability of fastest heat transfer? Variables: Independent Variables: Types of container Dependent Variables: Temperature of water in the given container, the cooling rate Controlled Variables: Starting temperature, amount of time given for heat transfer, the room temperature where the investigation is conducted, and the amount of hot water
  2. 2. Materials:  Water  Hot plate or Water Heater  Containers: Styrofoam, Foam, Metal, and Paper (3 containers per each type).  Beaker – 1000 milliliters  Beaker – 250 milliliters  Thermometer  Pipette  Stop Watch Procedure: 1. Fill in the 1000 milliliters beaker with water until it is almost full 2. Place the 1000 milliliters beaker on the hot plate 3. Turn on the hot plate and heat the water 4. Measure the water in the beaker until it is 60 degrees Celsius 5. Pour the heated water from the 1000 milliliters beaker into the 250 milliliters beakers until it is 50 milliliters depth 6. Use the pipette to adjust the amount of water in the 250 milliliters beakers as close as possible to 50 milliliters depth 7. Pour the water from the 250 milliliters beakers into the containers 8. Place thermometers into each containers 9. Start the timer 10. (After 5 minutes) Record the temperature of water in each container 11. Repeat steps 4-10 with new containers for 3 times 12. Collect the data carefully Data Collection: During the observation, it was noticed that at 60 degrees Celsius, there are plenty of water vapor. The vapor can be seen very easily when it rose against the surface of the medal container. Table 1: Temperature of Water Types of Container Temperature of Water (°C) ± 0.5 Uncertainties Average Temperature of Water (°C) Test 1 Test 2 Test 3 Styrofoam 48.0°C 49.0°C 49.0°C ± .5°C 48.0°C Foam 45.0°C 47.0°C 43.0°C ± 2.0°C 45.0°C Metal 33.0°C 37.0°C 35.0°C ± 2.0°C 35.0°C Paper 38.0°C 34.0°C 33.0°C ± 2.5°C 34.6°C Table 2: Heat Transfer Rate Type of Container Transfer Rate of Heat (°C / Min) Uncertainties Styrofoam 2.0°C ± 1% Foam 2.6°C ± 3% Metal 4.2°C ± 3% Paper 4.4°C ± 4%
  3. 3. Sample Calculations: Average temperature of water Heat Transfer Rate Uncertainty Styrofoam = (48 + 47 + 49) / 3 Styrofoam = (60 – 48) / 5 Styrofoam (49-48) / 2 = 48.00°C = 2.4°C = ± .5°C Graph 1: The transfer rate of heat of each container Transfer Rate of Heat (°C / Min) 8 7 6 5 4 Transfer Rate of Heat (°C / 3 Min) 2 1 0 Styrofoam Foam Metal Paper The graph shown above demonstrates the rate of heat transfer in each container. Note that Paper has the highest rate of transfer while Styrofoam has the lowest. The uncertainty is shown in the graph above to indicate the range of values of rate of heat transfer. The tests of heat transfer were tested for three times. Conclusion and evaluation: According to the data collection, the metal container did not have the fastest rate of heat transfer as predicted. It can be seen form the data collection that paper has the fastest rate of heat of 4.4°C when compared to the Styrofoam which has the lowest rate of heat transfer of only about 2.0°C. In addition, metal, the object that was predicted to have the fastest heat transfer rate was fairly close with 4.4°C rate of heat transfer. The uncertainties in this investigation are calculated for the fact that there are ranges of values in each investigation. It was quite extraordinary how the paper which has the starting temperature of 60°C where its temperature dropped to about 34°C within only five minutes. Paper was not predicted to have the fastest heat transfer for the fact that it is not a conductor of heat. On the other hand, metal, which could be seen in various occasions to attract large amount of heat such as cars that are out in the sun, was predicted to have fastest heat transfer is because it is a better conductor. Nevertheless, after the investigation, it was strange to have had found out that paper has the faster heat transfer rate.
  4. 4. The major weaknesses of this investigation are the room temperature that is not constant. This inconstant room temperature maybe the root cause of temperature changes where the data was collected within two days period. In addition, because the water temperature changes all the time, it cannot be kept at constant rate of 60°C. Therefore, it is difficult to make sure that the starting temperature is 60°C in every trials. To improve this investigation, the trials should be conducted in one day to make sure that there will be least room temperature changes. Also, more efficient tools can be used to control the temperature as precise as possible such as special room that has constant room temperature.