1. Pressure Vs Temperature A Second Look at Nature’s Natural Temperature Scale.

2. Experimental Design Open logger Pro. Set the sampling to “Events with Entry,” and then designate and calibrate the sensors. Open logger Pro. Set the sampling to “Events with Entry,” and then designate and calibrate the sensors. Allow the gas sample (in the Erlenmeyer flask) to sit at room temperature in the room temperature water bath for approximately 60 seconds. Then, close the portal and begin collection of the pressure and temperature data. Allow the gas sample (in the Erlenmeyer flask) to sit at room temperature in the room temperature water bath for approximately 60 seconds. Then, close the portal and begin collection of the pressure and temperature data. After the data is stored move the system to either the cold or hot water bath. Allow about a minute for the system to come to equilibrium and then capture the pressure and temperature data. After the data is stored move the system to either the cold or hot water bath. Allow about a minute for the system to come to equilibrium and then capture the pressure and temperature data. After the second data point has been captured bring the remaining water bath to your station and capture the data. After the second data point has been captured bring the remaining water bath to your station and capture the data. To lock the data for analysis select the stop button. From the analysis field select the linear graph option. To lock the data for analysis select the stop button. From the analysis field select the linear graph option. After the initial review of the graph, adjust the scaling until you can see the x- intercept. After the initial review of the graph, adjust the scaling until you can see the x- intercept. Use the interpolate option in the analysis field to trace the line until you hit the x-intercept. The x-intercept should be around -273 °C. Use the interpolate option in the analysis field to trace the line until you hit the x-intercept. The x-intercept should be around -273 °C.

3. Appearance of the Lab Station The photo on the left shows the ice water and hot water baths which are to be shared. For safety reasons the hot water bath is positioned next to the hot plate. The right side of the first photo also shows the computer, the collection probes and the room temperature water bath. Each station has a dedicated room temperature bath. The photo to the right shows a close up of the flask, and the two sensors (pressure and temperature).

4. Initial Collection Procedure In the top photo you can see (red box) that the valve is open and the atmosphere can interact with the gas inside the flask. In the bottom photo the valve has been closed (red box). The gas can only exit through the connection to the pressure gauge. Once the temperature and pressure stabilize strike the “keep” button and then the number 1 is recorded.

5. Ice Bath Data The bottom photo shows the growing linear relationship that is presented by the data. We expected the same relationship as the V Vs T Graph. Since the ability to claim territory through aggressive collisions is closely related to the pressure that is generated as a result of the energetic collisions the two behaviors are connected like twins. Clearly, when there is no energy to fuel the movement of the molecules there can be no pressure. Without pressure territory cannot be claimed. Disclaimer: Though the gas molecules cannot claim territory due to their behavior they can claim the territory occupied by their mass.

6. Hot Water Conditions It is important to keep the temperature at or below 40°C. If we run the experiment at a higher temperature we risk the sudden release of the pressure caused by dislodging the cork. A breach of this kind would change the population size which is controlled.

7. Graphing the Data As expected the graph is linear.

8. Fantastic Intercept Once again we collide with the x-axis at -273 °C.

9. First Graph of Data

10. Final Graph with x-Intercept of -273 °C

11. Final Thoughts As mentioned earlier there is a direct relationship between the pressure generated by a gas and the ability of that gas to obtain territory (occupy a volume). This lab allowed us to independently verify Nature’s Natural Temperature Scale. The laws that grew from these experiments ( P Vs T and V Vs T) require us to use the Kelvin scale. Never insert Celsius into any gas law equation. The DVM relationships that we are using are true only because we use Kelvin. Unfortunately we seldom use Kelvin as our daily thermometer. You must be prepared to convert Celsius to Kelvin and Kelvin back to Celsius. The equation you require to make these conversions came from this lab….K = °C + 273.

12. Lab Report Requirements As mentioned in class I want you to discuss the aggressive nature of gases. In that discussion you must explain how gases use their aggressive nature to take territory. You must clearly examine what is going on in the flask as we expose the gas system to the three different temperatures. Please be sure to use the language of science (independent and dependent variables, controls etc…). In a second paragraph discuss the data. Insert pictures from this powerpoint where appropriate. Fully explain what we mean by Nature’s Natural Temperature Scale. Make the experience real to the reader ….. That would be me. Every team did a fine job collecting the data. Your discussion of the data should include comments regarding what we look for in good data. Explore possible sources of error (we mentioned a big one the day before the lab). For the truly motivated student, discuss how we could quantify the possible impact of this major source of error. Use your math skills. The more you write the more you will learn.