Heat capacity of metals
Physical Science laboratory 062 built off of a 31 year old video tape title Eureka: Heat and Temperature the students viewed on Monday. The college had acquired the video in 1993. At the time I showed the video, I was unaware of the age of the video. Despite the age, the humor connected and the students laughed at a number of different sections.
I wanted to chase the idea of heat capacity, and I knew the lab had an eclectic collection of specific heat capacity materials. I opted to use Styrofoam cups as calorimeters because of their simplicity and insulation qualities.
I deliberately chose to avoid the mathematical formality of Q = mcΔT and the loss of heat by the heated metal objects and the gain of heat by the water. On a first run of the experiment I wanted the students to engage in a more open ended exploration of which metal held the most heat.
The experiment was by no means a discovery or constructivist oriented experiment per se. In a guided discussion I directed the students to fill each cup to the same level, to mass the metal, and to heat the metal to 100 °C. I then asked the students to measure amount of heat as the change in the temperature of the water per gram of metal mass. This is not the specific heat capacity, but is roughly half the specific heat capacity. Not exactly half the specific heat capacity, as detailed in an analysis of the data gathered by the students.
The laboratory wrapped up with my leading a question and answer session as to where the results agreed and disagreed. The variety of incomplete specific heat capacity sets was a real plus: the same metals were measured at different masses. The density of some metals had to be calculated to determine the probable metal.
I also asked for graph suggestions, and the students suggested a column chart.
The 11:00 section was tasked with exploring the discrepancies and attempting to verify the results of the 8:00 section. This went more quickly than the morning session, and, as is often the case, the 11:00 section was much more half-hearted and less enthusiastic. This is a common pattern and appears to in part be a result of the 11:00 lab spanning the lunch hour.
I wanted to chase the idea of heat capacity, and I knew the lab had an eclectic collection of specific heat capacity materials. I opted to use Styrofoam cups as calorimeters because of their simplicity and insulation qualities.
I deliberately chose to avoid the mathematical formality of Q = mcΔT and the loss of heat by the heated metal objects and the gain of heat by the water. On a first run of the experiment I wanted the students to engage in a more open ended exploration of which metal held the most heat.
End of lab wrap-up
The laboratory wrapped up with my leading a question and answer session as to where the results agreed and disagreed. The variety of incomplete specific heat capacity sets was a real plus: the same metals were measured at different masses. The density of some metals had to be calculated to determine the probable metal.
I also asked for graph suggestions, and the students suggested a column chart.
The 11:00 section was tasked with exploring the discrepancies and attempting to verify the results of the 8:00 section. This went more quickly than the morning session, and, as is often the case, the 11:00 section was much more half-hearted and less enthusiastic. This is a common pattern and appears to in part be a result of the 11:00 lab spanning the lunch hour.
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