Bare Probe Temperature Test

3 10 2012

I’ve completed a preliminary temperature test with the probe I made on the solar cooker today. All went fairly well, up until the point that I got bitten by a green ant in between my toes during one of the measurements. This resulted in me accidentally pulling the probe off of the cooking rack and, hence, ending the experiment prematurely. I did get good results none the less.

Bare probe on the cooking rack

One thing that I did note is that the wind had a big effect on my temperature readings. As can be seen in the data plot below, whenever a small breeze came up, the temperature would drop dramatically.

Graph of temperature readings during the test.

This makes me want to redo the experiment with the probe inside a glass jar, with possibly a slight vacuum applied. This way I can get some more accurate results and some more extreme temperatures if I apply a vacuum.

Bare Probe Test Data

As mentioned during the post on building the probe, I think that the temperature readings I am getting are lower then the actual temperature because of the exposed bit of the probe. Before the experiment was brought to a premature end by the ant bite, I was planning on using a pair of pliers to see if I could pull the probe from the graphite straight after removing it from the cooker. Since solder melts at approximately 190 degrees C, if the probe pulled out I would know instantly that the measurements were off. Why I think it may be that far out is because, directly after inserting the probe into the graphite during construction, I had a reading on my multimeter of approximately 140 to 150 degrees C. This is a far cry from the > 190 degrees I was expecting. However, I did not preheat the probe before I put it in so that could also result in the lower reading.

Anyway, I am pretty happy with these results, considering the wind factor. I may revisit these tests at a later date, but for now at least, I am going to refocus my energy onto my two major projects (the recumbent bicycle and high altitude balloon).




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