Heating Curve Lab

    Welcome back!  Today was the first day of the second semester.  Besides getting new seats and some old work back, we also began a new lab.  If you don't have it you can find it here (however this format is slightly different).  We will no longer be using the pre-lab, data, post-lab format.  The new outline for our labs is:


Title:
Lab Goal:
Data/Collections:  (includes data, labeled graph, and percent error)
Conclusion:  (includes claim (according to your data...), evidence (what data did you use 
                   that helped you make this claim?  How did you identify what ever you were 
                   looking for), and reasoning (does your data make sense?  Why might it not be
                   what you expected it to be?)


    In the lab, we filled a 400 mL beaker with about 150 mL of snow/crushed ice.  The goal of the lab was to find out the temperature at which ice melts and boils (using the heating curve).  The next step was to take the initial temperature of the ice.  My group got about -.5º C (however you should turn this number to Kelvin [add 273] because when calculating the percent error it will be difficult to work with Celsius whose freezing point is 0º).  
    
    Next, the beaker was placed on a hot plate and the heat was turned on halfway.  The crushed ice was stirred and every minute it's temperature was taken.  After all the ice melted the hot plate was turned on to full value.  We continued to stir the liquid and take its temperature every minute.  The hot plate was turned off after 3 minutes of boiling (100º C).  


    The data you got (temperature and time of the the different phases of the ice) will now be used to make a graph (recall earlier this year when we used excel to make tables and graphs with curves/lines).  Instead of writing a post lab, you will write up a conclusion summarizing the lab and explaining at what temperature the ice melted and boiled at and why this is so.  


    That was about it for today.  This lab is due wednesday.  Our test will be next thursday (02/03/11).  There is a webassign due tomorrow (tuesday the 25), and don't forget to start the second set of book problems which will be due on the day of the test.  We will also be turning in the first set of book problems that we did before finals.


The next scribe will be Ann Marie C.


Good luck!