Phy 232
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? **
After blowing water into the tube, I allowed it to vent to atmosphere. Since the tube was below water level, the pressure inside vented out by pushing water out.
** What happens when you remove the pressure-release cap? **
After blowing into the tube, I removed the pressure-valve tube (located above water level). Briefly water came out but so did air form the pressure valve tube.
** What happened when you blew a little air into the bottle? **
After blowing air (bubbles) into the vert column, I removed it from my mouth. The water level went up many centimeters. The length of the pressure-indicating tube also went back to the same position as atmosphere.
(It should have moved out due to the higher internal pressure.)
** 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: **
1000 N/m^2
10 cm
1%
1% of 1 x 10^5 is 1000, P=pgh,
** Your estimate of degrees of temperature change, amount of pressure change and change in vertical position of water column for 1% temperature change: **
3C
333 N/m^2
3.3 cm
Temperature change is in Kelvin. Atm is 22 C (or 295K)
1% of 295 is about 3C, 1/3 of 1000N/m^2 is 333, 1/3 of 10 cm is 3.3 cm
** The temperature change corresponding to a 1 cm difference in water column height, and to a 1 mm change: **
.295 C
.0295 C
** water column position (cm) vs. thermometer temperature (Celsius) **
23.1 C, 5 cm
Observed for 10 minutes and saw no changes.
** Trend of temperatures; estimates of maximum deviation of temperature based on both air column and alcohol thermometer. **
Since the thermometer is very sensitive, I would not touch, open windows nor run fans.
** Water column heights after pouring warm water over the bottle: **
23.1 C, 5 cm
pours a small cup of water on the bottle, level went up very quickly to by 11 cm. It more slowly dropped down but it did not return to existing level after 5 minutes. Suspect the towel under the bottle still had additional heat.
The towel could transfer heat to the water, which would then transfer it to the air in the bottle; the water would also have warmed slightly from the increased air temperature in the bottle, etc..
Adhesion between bottle and the tube could also have some effect.
** Response of the system to indirect thermal energy from your hands: **
Yes, the hands raised the water level by about 2 cm.
** position of meniscus in horizontal tube vs. alcohol thermometer temperature at 30-second intervals **
As the tube became horizontal, water position moved out by several cm. Very slight changes of the tube had an effect on position level. Temperature remained steady at 23.1 C.
** What happened to the position of the meniscus in the horizontal tube when you held your warm hands near the container? **
Level moved out until tape broke. Then level to the end of the tube.
Darn gravity kicks in.
** 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: **
Very little pressure is required to move horizontal.
Volumn change is 10 cm x pi x .09 cm^2 /4 = 0.707 cm^3
Had about 500 cm^3 of air. (not 1 l) 0.141% .707/ 500 x 100%
Very little change for temperature.
Water at 600K would be under pressure of about 600 psi. It it were vented to atmosphere, the water would be in a boiling state.
** Why weren't we concerned with changes in gas volume with the vertical tube? **
Significant change would be dependent upon how horizontal the tube is.
** 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: **
600 Pa,
about 2C
.7/3000 x 300 = 0.07C
** 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: **
141 cm
141 cm
45 degrees. not fully sure of this.
** Optional additional comments and/or questions: **
3.5 hrs.
** **
Neat experiment with the bottle of water and tubes. Nice to relate concepts to real case. Some of the details were confusing especially about tube caps and which tubes to use.
&#Good responses. See my notes and let me know if you have questions. &#