Your work on bottle thermometer has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
Your optional message or comment:
What happens when you pull water up into the vertical tube then remove the tube from your mouth?
At first I thought the water should stay in the tube, but when it didn’t I realized that with the cap off the pressure control valve, I was drawing more air into the container, thus increasing the volume of air in the container as I removed water by drawing it up into the tube. When I put the cap on the pressure relief valve I sealed the system at a pressure lower than room pressure, when I removed the tube from my mouth the pressure in the room forced the water back into the container.
I actually performed this experiment several times because I thought the water should have stayed in the tube. I leak tested the system several times. Was I wrong to think that or is my assumption correct?
you are correct in your explanation. You reduced the pressure in the tube, allowing the now-greater pressure in the bottle to force water up the tube. When you allowed the pressure to return to atmospheric, the water was indeed forced back down into the tube until it reached its original level.
What happens when you remove the pressure-release cap?
At first I thought the water should stay in the tube, but when it didn’t I realized that with the cap off the pressure control valve, I was drawing more air into the container, thus increasing the volume of air in the container as I removed water by drawing it up into the tube. When I put the cap on the pressure relief valve I sealed the system at a pressure lower than room pressure, when I removed the tube from my mouth the pressure in the room forced the water back into the container.
Then the volume of water going back into the container increased the pressure again to equalize it.
What happened when you blew a little air into the bottle?
As I blew air into the vertical tube the air column at the end of my pressure indicating tube shortened, i.e. the water was forced towards the capped end by the excess pressure in the system. When I removed the tube from my mouth this placed the end of the tube at room pressure once again and thus the excess pressure in the system forced water up the vertical tube to equalize the pressure in the system. These occurrences were exactly what I had anticipated.
Your estimate of the pressure difference due to a 1% change in pressure, the corresponding change in air column height, and the required change in air temperature:
1k
1.5cm
1%
Since 100kPa is equal to 100kN/m^2 then the pressure would change by 0.01x 100kN/m^2, which is 1kN/m^2.
The air column length is equal to the inverse ration of the pressure change in the container, since the pressure in the container forces the water towards the end of the pressure measuring tube. I used the 3xreduced ruler to measure the air column so a 1% reduction in this would have been equal to approximately 1.5cm.
Since pressure and temperature are proportional when volume is held constant it would take a 1% change in temperature to cause a 1% change in pressure.
Your estimate of degrees of temperature change, amount of pressure change and change in vertical position of water column for 1% temperature change:
3K
333.3310N/m^2
3.33cm
If we assume the temperature is at 300K then a 1% change would equal 3K and the pressure would change by 1kN/m^2 for 3K. Then for 1K the pressure would change by (1KN/m^2)/(3K)=333.33N/m^2. The vertical water column would then change by 3.33cm.
The temperature change corresponding to a 1 cm difference in water column height, and to a 1 mm change:
0.30K
0.03K
If 1K equals 3.33cm change (1K/3.33cm) then 0.3K/1cm and 0.03K/0.1cm are the same ratios.
water column position (cm) vs. thermometer temperature (Celsius)
I monitored my room temperature for 15 minutes, several times, and it did not fluctuate nor did the vertical water column. I tried this several different times and still observed no change that I could see. However I do know that the graph for temperature vs. pressure should be linear.
Trend of temperatures; estimates of maximum deviation of temperature based on both air column and alcohol thermometer.
Again, I monitored my room temperature for 15 minutes, several times, and it did not fluctuate nor did the vertical water column. I tried this several different times and still observed no change that I could see. However I do know that the graph for temperature vs. pressure should be linear.
I performed this experiment several times because I didn’t read a fluctuation at this point. But each time my results were the same.
Water column heights after pouring warm water over the bottle:
The alcohol thermometer reading was 25*C.
Once the water was poured into the container surrounding the container of water and air I was observing, the water column suddenly dropped from 10cm to about 7.8cm, then shortly there after it began to rise again. I do not understand this but it did this every time I attempted this experiment.
You didn’t ask for the change in water column height relative to time but I’ll add it anyway.
0,7. 8
15, 7. 8
30, 7. 8
45, 8.6
60, 9.4
75, 9.6
90, 10.0
105, 11.0
120, 11.6
135, 12.4
150, 12.8
165, 13.0
180, 13.6
195, 13.7
210, 13.8
235, 13.9
250, 14.0
265, 14.1
280, 14.1
295, 14.2
310, 14.2
It took a few about 60 seconds for a change in temperature to take place because it took 60 seconds for a change in the water column to start. I’ll assume it took this long because the temperature of the water I poured in wasn’t quite hot enough considering the thermal conductivity of the container wall. Once this change started the water column height went from 7.8cm to 14.24cm before settling out and the air column reduced from about 16.5 to 15.8 relative to the 3x-reduced ruler.
Response of the system to indirect thermal energy from your hands:
Yes, the heat transferred from my hands definitely warmed the air in the bottle. I rubbed my hands vigorously on my pants to give them more heat and then held them next to the container wall. The water column height went to well over 15cm.
position of meniscus in horizontal tube vs. alcohol thermometer temperature at 30-second intervals
I know the water column is more sensitive in this position but my room temperature did not fluctuate enough to indicate on the alcohol thermometer nor were there any fluctuation in the horizontal column that couldn’t have come from vibrations.
Maybe I’m looking at something wrong.
What happened to the position of the meniscus in the horizontal tube when you held your warm hands near the container?
The water column is much more sensitive in the horizontal position because the altitude of the end of the tube is less. My water column shot out fairly far compared to the vertical counterpart.
Pressure change due to movement of water in horizonal tube, volume change due to 10 cm change in water position, percent change in air volume, change in temperature, difference if air started at 600 K:
588N/m^2(very little)
0.7cm^3
1.35%
1.35%
It would double the values
Why weren't we concerned with changes in gas volume with the vertical tube?
This volume change was insignificant compared to the pressure change required to raise the water 10cm vertically above the container top, as compared to the horizontal tube.
In the horizontal position it took very little pressure to move the water column. And once we made the transition from vertical to horizontal position or movement of water, the pressure increase was minimal and the air volume increase was what was moving the water.
Is this a correct assumption?
Very much so.
Pressure change to raise water 6 cm, necessary temperature change in vicinity of 300 K, temperature change required to increase 3 L volume by .7 cm^3:
Not sure on this part
6 cm of water column height corresponds to about 600 N / m^s in pressure (just rho g h).
.7 cm^3 is .00027 of the 3 liters, so temperature should change by factor .00027. At 300 K this would be a change of about .08 Kelvin.
1.23%
The effect of a 1 degree temperature increase on the water column in a vertical tube, in a horizontal tube, and the slope required to halve the preceding result:
3.33cm
0.007cm^3
30*
If the tube is not truly horizontal you may be sensing a change in pressure vs. a change in volume.
Optional additional comments and/or questions:
I’m clear on the bottle engine theory, as far as PV=nRT and if nR/V is held constant then the pressure increase is proportional to the temperature change, and vise versa for nR/P being held constant and volume being proportional to the temperature change. And with that said pressure and volume are inversely proportional when nRT is held constant. I’m also clear on how the ratio of air column change in length is inversely proportional to the pressure in the container, and as to why the pressure increase forces water up the vertical tube. Also clear on why that pressure is equal to ‘rho(g)’h. Sometimes however I’m not clear on what you’re asking for or maybe it’s what I’m looking for. Or maybe I juts second guess my results and tend to confuse myself. I guess that’s the draw back of distant learning-not having a lab partner to brainstorm with. Over all though the lab was good and I learned quite a lot about thermal dynamics in this section of the course. Just hope I can regurgitate that while taking the test.
Thanks
You appear to have a good deal of insight into these processes, and most of your explanations were excellent. I believe my note(s) will help answer your remaining questions; if not, be sure to let me know.