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course phy 242
june 13 at 1 pm
Comparing the state of the bottle before and after you squeeze:Does the amount of air in the bottle increase or decrease?
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Decrease, because as you squeeze the bottle the air is now getting pushed out of the tube
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Does the volume of air enclosed in the bottle increase or decrease?
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Decrease, because since volume and pressure are inversely proportional, the pressure increases so the volume decreases.
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Does the pressure in the bottle increase or decrease?
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Increase, because as previously stated as volume decreases , pressure increase.
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Does the temperature of the air in the bottle increase or decrease?
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Remains the same since volume is decreasing and pressure is increasing, the temperature is kept the same.
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Be sure you have explained all your answers.
Now cap the end of the tube and give the bottle a good squeeze, without straining yourself.
Comparing the state of the bottle before and after you squeeze:
Does the amount of air in the system increase or decrease?
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Remains the same since the system is closed.
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Does the volume of air enclosed in the system increase or decrease?
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Decrease since air is being pushed out of the bottle to the tube.
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Does the pressure in the system increase or decrease?
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Increase since I am exerted force onto the bottle by squeezing.
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Does the temperature of the air in the system increase or decrease?
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Remains the same since volume is decreasing and pressure is increasing, the temperature is kept the same.
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Part 1B
Does the air column get longer or shorter? By what percent do you estimate the length of the column changes?
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Shorter by 6%, because you are not exerting an immense about of force jut a moderate.
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Does the volume of the air column increase or decrease? By what percent do you estimate the volume of the column changes?
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Decreases by 6%, since a pressure increased by squeezing , and volume and pressure are inversely proportional , then the volume would decrease .
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Does the number of molecules in the air column increase, decrease or remain the same? By what percent do you estimate the number of molecules changes?
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Remains the same, because now they are under a greater pressure, making it even harder to squeeze.
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Does the mass of the air in the air column increase or decrease? By what percent do you estimate the mass of the air in the column changes?
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Remains the same since the number of molecules are the same and can’t escape.
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Does the pressure in the air column increase, decrease or remain the same? By what percent do you conjecture the pressure in the column changes?
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Increase by 6%, due to the force exerted through the increase of pressure.
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Does the pressure in the bottle increase, decrease or remain the same? By what percent do you conjecture the pressure in the bottle changes?
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Increase by 6%, because force is also exerted to the bottle during the squeeze, which is converted to pressure.
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When you hold the bottle in the squeezed position, with the water plug stationary, the pressure in the bottle results in a force on the plug which pushes it toward the capped end, while the pressure in the air column results in a force that pushes the plug away from that end. Which force do you think is the greater, or are they equal?
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Since water plug is stationary or not moving toward the bottle cap then both forces are equal.
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Which do you think is greater, the pressure in the bottle or the pressure in the air column?
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The pressure in the air since it is congested in a smaller tube or volume.
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Measure the length of the air column.
What is the length of the air column?
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15 paper clips.
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How far would the water plug have to move to make the air column 10% shorter?
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1.5 paper clips
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Squeeze the bottle so the air column becomes 10% shorter. It's up to you to figure out how to tell when it's 10% shorter. If you can't squeeze hard enough to achieve the 10% difference, then figure out what percent you can manage and note the percent in your answer.
On a 1-10 scale, with 10 the hardest squeeze of which you are capable without risking injury, how hard did you have to squeeze the bottle and what percent change did you achieve in the length of the air column?
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7, I achieved 1.5 paper clips distance and had the squeeze to go a one more paper clip.
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Now, using the same 1-10 scale, give the bottle squeezes of 2, 5 and 8. Estimate the percent changes in the length of the air column.
What were your percent changes in air column length?
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A 2 moved the water about a quarter of paper clip, which is 1.3%, a 5 moved it 1 paperclip which is 6.7% and a 8 move it 1.75 paper clip which is 11.7.
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Now by heating and/or cooling the bottle, what extremes in air column length can you achieve? Careful not to melt the bottle. It won't handle boiling water, and you shouldn't mess with water hot enough to scald you or cold enough to injure you (e.g., don't use dry ice, which in any case is too cold for the bottle, and certainly don't use liquid nitrogen).
Report your results:
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When the bottle was warmed the air column decreased while when the bottle was cooled the air column increased.
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Starting with the cap in place on an empty bottle, siphon water from an adjacent full bottle. Allow the siphon to run a few minutes until the water levels in the two bottles stabilize.
Estimate the percent change in the volume of the air in the capped bottle.
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Around 25%.
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Estimate the percent change in the number of molecules in the air within the capped bottle.
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There was no molecules that could escape, therefore 0%.
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Estimate the percent change in the volume of the water in the open bottle.
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50%
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What do you think is the percent change in the air pressure in the capped bottle?
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Since volume and pressure are inversely proportional, then if the volume changed by 25% increase then the air pressure will decrease by 25%.
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What is the difference in the two fluid levels?
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There is none , they are both have the same level.
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What is the percent change in the number of air molecules in the capped bottle?
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0%
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Raise the open bottle as high as possible without disturbing the capped bottle. Allow time for the water levels in the two bottles to stabilize.
What percent of the volume of the capped bottle do you now estimate is occupied by water?
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About 60%.
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Estimate the percent change in the number of molecules in the air within the capped bottle.
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0% because the bottle is capped and air molecules can’t escape.
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By what percent do you estimate the pressure in the capped bottle exceeds the original pressure (i.e., the pressure when the bottle was first capped)?
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35% since the difference of the original volume and the volume gained in this experiment is 35% and volume and pressure are related.
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What percent of the uncapped bottle do you estimate is now occupied by air?
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About 70%.
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What is the difference in the two water levels?
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The open capped has lower water level than that of the closed cap bottle.
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Return the uncapped bottle to the tabletop. What happens?
What is now the difference in the two water levels?
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The water from the capped goes into the uncapped until they stabilize into the same level.
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What do you think is the pressure in the uncapped bottle as a percent of its original pressure (before the bottle was capped)?
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The pressure in the uncapped bottle is the same as its surrounding if its uncapped but when it is capped there is specific amount of pressure in which can show its effects through squeezing it.
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Add the extension to the tube, so that by squeezing you can force water from the bottle into the tube. Squeeze hard enough to raise the water to as high as possible into the tube. Evaluate how hard you had to squeeze, on the 1-10 scale you used in part 1b. Measure how far you were able to raise water in the tube above the level of the water in the bottle.
How high did you raise the water, and how hard did you have to squeeze (using the 1-10 scale)?
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I got the water to come out of the tube with a squeeze of 10.
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Give the bottle a squeeze corresponding to 1 on the 1-10 scale, and observe how high water rises. Then give it another squeeze, halfway between 1 and the squeeze you used to raise water to the top of the tube. Do this blind. Don't look at the tube, just feel the squeeze. Then look at the tube and see where the water is.
Report a table of water column height vs. squeeze.
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1, 15 cm
5, 33 cm
&#This looks very good. Let me know if you have any questions. &#