Lab: Finding Absolute Zero

Conclusion and Evaluation:

The results support the hypothesis stated above, as the temperature of the water rises, the volume increases as well. The volume does not increase proportionally with the temperature. The graph shows that the results I measured were not very accurate since the absolute zero I obtained after drawing the line of best fit is -435°C instead of the accepted value of -273.15°C, there is a gap of 162.15°C between those two values. The graph shows how inaccurate my readings were, the data points do not increase constantly, instead, the slope one would obtain, if one were to draw a line connecting those pints would approach 0, in other words, the line would become horizontal (similar to a cubic function).

There were many errors which manipulated this experiment. First one is as always human error, the use of analogue measuring devices meant that one had to read off the values with the human eye and since humans tend to round values off to make them simpler, the readings get manipulated. It is also difficult or even impossible to read off the volume of the open-ended glass capillary tube at exactly the moment when the temperature reaches a certain point, since both factors change (rise) rapidly.

Second error was that the beaker had an open top, meaning that heat will be released very easily. With an open lid, evaporation will occur once the water is hot enough, if the water evaporates, and then the volume will start to decrease (since obviously less water would be in the beaker). The lack of isolation around the beaker also allowed the heat to escape to the surrounding. If the heat cannot be kept within the beaker, then it is obvious that results will be manipulated. Third error was that the thermometer was very close to the immersion heater, which could have led to manipulated results as well.

Another source of error was that most of the open-ended glass capillary tube was not in the water, but was sticking out, which would lead to a measurement “mix” between the volume of the water and the air surrounding it.

There are a couple of things one could do differently to make this experiment more successful. It is important to isolate the beaker and seal it to obtain accurate results. Isolating the beaker does not have to be complicated, one could wrap a couple layers of kitchen paper or a layer of thin Styrofoam around the beaker, to provide a bit of isolation. One could use a paper or plastic plate as a lid; one should not use glass, since you still need holes for the immersion heater, the open-ended glass capillary tube and the thermometer. The plate might not stop all the evaporation or the heat from escaping, but the results would be more accurate, than if you had an open beaker.

One should also use a high beaker, where one could pour enough water into, to cover the open-ended glass capillary tube almost to the top. Not only should one prevent heat from escaping, one should also have better equipment to measure the volume at different temperatures accurately. The simpler method would be to have electronic measurement devices. The more complicated version would be to hook up the equipment to a computer (if that is even possible) and let the computer register the data at different measuring points.

As a conclusion, I would say that this experiment was a failure for me since my result for the absolute zero is far from the accepted -273.15°C or 0 K.