| 1 | Equilibration of temperatures |
|
|
| Main | Hot water is poured into one of two compartments of a well insulated container. Cold water is poured into the other part separated only by a thin metal wall. A magnetic stirrer is used to make sure the water is always well mixed in both parts. The temperatures of the water in the two compartments are recorded. In a second experiment, a cold copper cylinder is immersed in hot water. The temperatures of water and of copper are recorded as functions of time. More…
 
|
| Photographs |
|
| Movies | |
| Data files | |
| Model files | |
| |
| Sections | |
| |
Description | DESCRIPTION OF EXPERIMENT |
| Experiment | First experiment: Hot water is poured into one of two compartments of a well insulated container. Cold water is poured into the other part separated only by a thin metal wall. A magnetic stirrer is used to make sure the water is always well mixed in both parts. The temperatures of the water in the two compartments are recorded.
Second experiment: A cold copper cylinder is submersed in hot water. The water is inside a glass container inside a heavily insulated cylindrical container. A magnetic stirrer is used to make sure the water is always well mixed. The temperatures of the water and of the inside of the copper cylinder are recorded as functions of time. The thermometer for the copper is inserted in a hole near the center of the cylinder.
|
| Dimensions | See Investigation 11 and Investigation 12
|
| |
Sections | |
| |
Assignment | A POSSIBLE PATH THROUGH THE INVESTIGATION… |
| Basics | Investigate both experiments, make sure you understand the setup of the system and the initial conditions. Plot the data to get a feeling for the process. Create a word model for the systems and the processes. Create the structures of system dynamics models—without details of parameters.
|
Particulars | Create a system dynamics model for the first experiment by copying a model of the equilibration of water (or oil) levels in two equal communicating fluid tanks. Change names of variables, introduce data, set initial values and perform a comparison of simulation and experiment. (Do not use any thermal theories, simply see how far the analogy goes.) Try to use the model for the second experiment. See which parameter(s) you have to change to get a satisfactory agreement between model and data. |
| |
Sections | |
| |
Model | MODEL EQUATIONS AND MORE… |
|
| |
| |
Sections | |
| |
Questions | SOME SIMPLE QUESTIONS… |
| 1 | What is the basis of a possible comparison of the phenomena seen in Experiment 1 and 2 with phenomena observed in hydraulics? Can the comparison also be made with electric phenomena? |
2 | Transform the model of the equilibration of liquid levels in two identical liquid tanks to the case of thermal equilibration. What thermal quantities do you introduce? Which thermal quantities are compared to which fluid ones? |
| 3 | If you use he hydraulic model to understand the equilibration of temperatures in Experiment 1, can you independently determine all necessary thermal parameters, or only combinations of parameters? What additional information would you need, if any? |
4 | If you want to determine quantities of heat, are you free to introduce a new measure (such as "one unit of heat changes the temperature of 1 kg of water by 1 Degree")? |
5 | What is different about Experiment 2 compared to Experiment 1? What must be changed in the dynamical model for Experiment 1 if it is to be applied to Experiment 2? |
6 | What is the role of energy in the equilibration of fluid levels in communicating tanks? Can this role be transferred to thermal processes? |
| |
Sections | |
| |