Hello, Could somebody help me on these questions? I have listed my thoughts and ideas - if they are incorrect could somebody please correct them or provide a detailed explanation to help me work out the right answer.
Thanks so much.
1) Why is a lighter oil better to use than mercury in a manometer?
> Is this because light oil has a lower density compared to Mercury and it floats ?
2) A student suggested that the height would be doubled on the manometer tubes if they were reduced to half the diameter. Comment on this suggesstion.
> I think it is true because the greater the density the greater the iquid sinks and also causes the diameter reduces.
3) You could say that each mass inside the Galelio thermometer is calibrated to a specific temperature. Explain what this means.
> I think it means that the masses inside are measured to find the different densities and pressures.
4) Explain why having an absolute temperature scale like the Kelvin scale might be better that the other scales like fahrenheit and celcius.
> Is this because it allows to measure the specific temperatures which can be used to calculate the absolute density ?
Hey EM, This is great; exactly the way one should be using the website! 1) Lighter densities reduce the pressure range but allow for more accurate measurements (the resolution is increased). 2) It will have no effect as the dimensions do not impact the height of the fluid. 3) This is a very good passage in understanding how a Galileo thermometer works: “The basic idea is that as the temperature of the air outside the thermometer changes, so does the temperature of the water surrounding the bubbles. As the temperature of the water changes, it either expands or contracts, thereby changing its density. So, at any given density, some of the bubbles will float and others will sink. The bubble that sinks the most indicates the approximate current temperature. Consider this example: Let's say there are five bubbles in the thermometer: A blue bubble that represents 60 degrees A yellow bubble that represents 65 degrees A green bubble that represents 70 degrees A purple bubble that represents 75 degrees A red bubble that represents 80 degrees The blue bubble (60 degrees) is the heaviest (densest) bubble, and each bubble thereafter is slightly lighter, with the red bubble being the lightest. Now, let's say the temperature in the room is 70 degrees. Since the surrounding air is 70 degrees, we know the water inside the thermometer is also about 70 degrees. The blue and yellow bubbles (60 and 65 degrees, respectively) are calibrated so that they have higher densities than the water at this temperature, so they sink. The purple and red bubbles each have a density that is lower than the surrounding water, so they float at the very top of the thermometer. Since the green bubble is calibrated to represent 70 degrees, the same temperature as the water, it sinks slightly so that it is floating just below the purple and red bubbles -- thereby indicating the room's temperature!” 4) Absolute Zero is at -273.15 Celsius or 0 Degrees Kelvin. This is the lowest possible temperature - a point in which atoms completely stop moving. So it makes sense to set this at 0 and to create the temperature scale accordingly. Celsius uses 0 Degrees C for the freezing point of water and 100 degrees for its boiling point. This is good for general use but not necessarily scientific use.