PHY 122
Your 'bottle thermometer' report 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? **
The water in the vertical tube moved down toward the bottle. The air column at the end of the pressure-indicating tube moved slightly when I removed the tube from my mouth.
We increased pressure in the bottle.
** What happens when you remove the pressure-release cap? **
Yes, I believe air will escape from the system when the cap was removed from the pressure-valve tube.
The air was escaping from the system; therefore, the pressure inside the bottle was decreasing because atmospheric pressure was now able to equalize the system.
** What happened when you blew a little air into the bottle? **
o When I blew air through the vertical tube the water in pressure-indicating tube moved to the right.
o The length of the air column in the pressure-indicating tube changed length because we were increasing the pressure in the bottle which increased the pressure in the left of the tube. The pressure was greater on the left hand side than on the right hand side.
o When I removed the tube from my mouth the water in pressure-indicating tube continued to flow towards the area of less pressure (right hand side of the tube)
There was no movement in the vertical tube.
o The low pressure I applied by using my diaphragm increased the pressure in the bottle. The pressure had no where to go but into the pressure-indicating tube. The pressure in the pressure indicating tube increased to the left and pushed the water in the pressure-indicating tube to the right.
o I would have expected the water in the pressure-indicating tube to move back to its original position.
** Your estimate of the pressure difference due to a 1% change in pressure, the corresponding change in water column height, and the required change in air temperature: **
26.5 C
o It was about 25.5 cm
o It was approx. 15.4 cm above the top of the bottle.
o It would change by approximately 1 N/m^2
o The corresponding height would change by 1%.
o The air temperature would have to change by 1% as well.
** Your estimate of degrees of temperature change, amount of pressure change and change in vertical position of water column for 1% temperature change: **
o It would change by approximately 30 K.
o The change would be inversely proportional to the change in temperature.
o It would change by 1% of its original height.
** The temperature change corresponding to a 1 cm difference in water column height, and to a 1 mm change: **
About 1 degree Celsius temperature change would correspond to about a 3.75 cm change. I made this estimate based on the fact that when the bottle of water was placed in boiling water the water moved up the air column about 20 cm.
It would correspond to about a 37.5 mm change.
Report your two numerical estimates in the first two lines below
I made my estimates using the concept that when the temperature of the gas inside increases this also increases the pressure inside. I assumed, after watches another experiment, that the increase from room temperature to boiling water would increase the column length about 20 cm to the top of the tube.
** water column position (cm) vs. thermometer temperature (Celsius) **
o Interval 1 14 cm, 26.1
o Interval 2 13.8 cm, 25.8
o Interval 3 13.6 cm, 25.8
o Interval 4 13.6 cm, 25.8
o Interval 5 13.5 cm, 25.8
o Interval 6 13.4 cm, 25.7
o Interval 7 13.4 cm, 25.7
o Interval 8 13.3 cm, 25.7
o Interval 9 13.3 cm, 25.5
o Interval 10 13.2 cm, 25.7
o Interval 11 13.1 cm, 25.8
o Interval 12 13.0 cm, 25.8
o Interval 13 13.0 cm, 25.8
o Interval 14 13.0 cm, 25.8
o Interval 15 13.0 cm, 25.8
o Interval 16 13.0 cm, 25.8
o Interval 17 12.9 cm, 25.7
o Interval 18 12.9 cm, 25.7
o Interval 19 12.8 cm, 25.8
o Interval 20 12.8 cm, 25.8
** Trend of temperatures; estimates of maximum deviation of temperature based on both air column and alcohol thermometer. **
The height of the water column decreased by a total of 1.2 cm in 10 minutes. The average decrease per minute was .04 per 30 second interval.
The maximum deviation for temperature over the 10-minute period was .6 C. the average fluctuation was .03 per 30 seconds.
** Water column heights after pouring warm water over the bottle: **
o 25.2 Celsius.
o 14.2, 14.5, 14.8 cm
** Response of the system to indirect thermal energy from your hands: **
Yes, my hands warmed the air in the bottle. The height of the water moved .7 cm.
** position of meniscus in horizontal tube vs. alcohol thermometer temperature at 30-second intervals **
Interval 1 9.1 cm, 25.8
Interval 2 9.1 cm, 26.0
Interval 3 9.1 cm, 26.1
Interval 4 9.0 cm, 26.3
Interval 5 9.0 cm, 26.5
Interval 6 9.0 cm, 26.5
Interval 7 9.0 cm, 26.8
Interval 8 9.0 cm , 26.8
Interval 9 9.0 cm , 26.8
Interval 10 9.0 cm, 26.9
** What happened to the position of the meniscus in the horizontal tube when you held your warm hands near the container? **
My hands did not move the water in the tube.
** 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: **
o The change in pressure was minimal; too minimal to say that there was a pressure change.
o Volume equals cross sectional area x length = 3 cm^3
o The volume inside the container would have to change the same.
o An equal change in temperature would be required to achieve this change in volume.
o The temperature would have to change by twice as much.
oI used the combined gas law and reasoning.
** Why weren't we concerned with changes in gas volume with the vertical tube? **
We were not concerned with the volume change in the vertical tube, only in the length of the air column in the pressure-indicating tube. The change in vertical tube volume would not have made a significant difference in our estimates of temperature change.
** 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: **
o The pressure of the gas would have to increase by 60%.
o The temperature would have to change by 180 K.
o You would have to increase the temperature by 6.37% in order to compensate for the additional volume occupied by the water in the tube. Assuming a temperature near 300 K, the temperature would increase to about 319.11 K.
** 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: **
I used the Ideal gas law and the combined gas law to determine the relationships between pressure, volume, and temperature. Volume and temperature are inversely related whereas volume and pressure are linearly related.
o It would have to change by 4 cm.
It would have changed by 7 cm.
o In about 54 minutes the change in the position of the meniscus would be half as much as my last result. The change in slope (change in y over change in x) would be - .2484375.
** Optional additional comments and/or questions: **
3 hours
** **
It would have been helpful to have a visual representation of the experiment for the first few parts.
&#Your work looks very good. Let me know if you have any questions. &#