An adiabatic process occurs when there is no heat exchange with the surroundings, Q=O. In order to successfully accomplish this the process must be done very fast to ensure heat is not lost. Using a fire syringe we can mimic this process with the below setup.
However, before we could see what occurs he had to figure out what the final temperature inside the fire syringe would be when the volume of air inside was compressed rapidly. In order to do this we had to take several measurements and use those values to calculate initial volume of the air column and final volume.
After we found the needed values we calculated the final temperature using what we know about adiabatic expansion and got the following:
We determined that the final temperature inside of the air column to be 1125 K, or 1565.6°F. This is a very high temperature and based on this value we expected the cotton ball inside to ignite. The following video shows what actually happened.
Video: Fire Syringe
Screenshot: Combustion inside Fire Syringe
Like we anticipated the cotton ball did in fact ignite when the air column was compressed rate. However, all we know for sure is that the temperature inside the fire syringe was greater than the flash point of the cotton ball. Our calculated value for final temperature may be a bit off because it is based on estimated measurements.
ActivPhysics
Our next experiment included doing questions 1-6 in ActivPhysics' Thermodynamics section 8.4.
Questions 1 to 3
Answers 1 to 3
Question 1: We chose the linear graph with a positive slope because we know that the relationship between volume and temperature is directly proportional. Therefore, if volume increases, then the temperature also increases at constant pressure.
Question 2: For this we also chose the linear graph with a positive slope because we know that the relationship between pressure and temperature is directly proportional. Therefore, if pressure increases, then the temperature also increases at constant volume.
Question 3: We chose the inverse graph to depict the relationship between pressure and volume because we know it is inversely proportional. If the volume increases, then the pressure must decrease to keep pressure constant.
Answer 4 and 5
Using the ideal gas law we calculated initial and final conditions to find our unknown.
Question 6
Answer 6
Using the ideal gas law we used the initial and final pressure and volume to calculate final pressure under those specific conditions.
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