LOL Graphs, Quantitative Energy, and Icy Hot

      This past week, we completed worksheets that covered quantitative energy problems and LOL graphs. These main ideas connect with each other because they all deal with energy being absorbed or lost. We also performed the Icy Hot lab, where we discovered what a heating curve looked like.

LOL Graphs We received two worksheets dealing with LOL graphs. We were given a situation such as "a cup of coffee cools as it sits on the table". Then we filled in the initial and final graph. E_{th represents the temperature. 1 bar stands for 0}°_{C, 2 bars stand for 25}°_{C, 3 bars stand for 60}°_{C, and 4 bars stand for 100}°_C. E_ph represents the phase, i.e., solid, liquid, or gas. 1 bar signifies a solid, 2 bars signifies a liquid, and 4 bars signifies a gas. For this particular problem, the initial E_{th is 4 bars, because it is stated that the cup of coffee is hot. The final} E_{th is 2 bars, because the cup of coffee should've cooled down to room temperature. The initial and final} E_{ph are both 2 bars, because the  coffee always stayed a liquid. After we filled in the graphs, we drew how many "bars" of energy was gained or lost. In this problem, 2 bars of energy was lost.}

cup of coffee problem

_{Quantitative Energy Two worksheets were given to us relating to quantitative energy. Using one of two formulas given to us, we solved each problem. The formulas were} Q=m*c*ΔT and Q=m*Hv or m*Hf.  _{We were also given energy constants. It takes 334 J/g to melt or freeze. It takes 2260 J/g to evaporate or condense. The heat capacity of solid water is 2.1 J/g*}°_{C. The heat capacity of liquid water is 4.18 J/g*}°_C. 

example of a quantitative energy problem

_{Icy Hot Lab In this lab we discovered what a heating curve looked like. We first attached a pressure sensor to the LabQuest interface. We then placed a temperature probe in a cup of ice and began stirring. When the temperature stopped dropping, we turned on the hot plate to high and immediately started Experiment on LoggerPro. A couple minutes after the water boiling, we turned the hot plate off. Afterwards, we printed out our heating curve. The results was a step formation.}

temperature probe stirring melted ice

our heating curve graph

      _{We came to know and understand the ideas this week by completing worksheets and labs. I still have a few questions about quantitative energy. My participation this week was good because I contributed to class discussion. I would rate my understanding of all the ideas this week an 8 because I'm still not sure about quantitative energy. I don't think I need to work on anything. My ideas have changed because I know more now than I did in the beginning of the week.}