Temperature and Heat 2/24/2014

Today we were introduced to Thermodynamics.  We learned that heat get transferred through convection, conduction, and radiation. We mainly focused on heat transfer through conduction. We got our feet wet by simple mixing of water and averaging the final temperature. Next, we acknowledged that things can be more complex by introducing different models. We learned the fundamental equation Q=kA (dT/dx) ot Q=kA(Th-Tc)/L where Q = Heat Flow; k = Thermal Conductivity; A = Surface Area; L = thickness; Th = hotter temp; Tc = cooler temp; R = Thermal Resistance Value.

Brain Storm and solving for heat transfer scenarios

We brainstormed in groups about how these parameters relate to another as we did various mini labs to support our results.  First, we tried to heat cool water inside an aluminum can by putting the can inside a foam cup filled with hot water.  We measured the resulting temperature with probes and plotted it with Logger Pro.  The result is straight forward and we fitted it into a linear characteristic.

Logged temperature versus time

We then analyzed different materials such as copper and aluminum and saw how they would act deriving from our equations.  We found our the higher the R-value for thermal resistance, the lower the k conductivity as they share an inverse relationship R = L/k.

Heat conductivity through different metals.

The results of the mini labs were a little off due to many uncertainties such as measurement, different probes, different stirring fingers.

Finally, we experimented heating through the means of electricity.  We used an Immersion heater to heat 200ml of water for 20 seconds as we measure the Wattage output.  

We plotted the graph as the temperature rises and with the help of Professor Mason, we obtained the hear versus temperature graph.  Further analyzing the liner graph, we asked ourselves: "What is the representation of this slope??"  Until now, we think it might be the characteristic of our heated element (in this case, water) and how easy/hard it is to react to heat.  

Heat v.s Temperature plot

It turns out that water is pretty temperature resistant!!

Last but not least had to rush out due to an Access Transportation Chaos:   but overall, it was a nice 1st day back to school~ STRESS IS OFFICIALLY ON!!! 

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