Experiment: Ratio of the principal specific heat capacities of air

In summary: Your Name]In summary, the forum member performed an experiment to find the ratio of specific heat capacities of air using a container, hand pump, and pressure sensor. The result obtained was γ=1.29±0.01, which may be considered a good result due to its small uncertainty. However, it is important to also consider the accuracy of the result and potential sources of error, such as not allowing enough time for the air to reach room temperature. Further information about the experimental setup and procedure would be helpful in determining the accuracy of the result. It is recommended to discuss these factors in the report and suggest ways to improve the experiment in the future.
  • #1
moonkey
26
0

Homework Statement


To find the ratio of the specific heat capacities of air (γ).


Homework Equations


PVγ=constant


The Attempt at a Solution


I performed the experiment a number of times to get an average for γ

The experiment consisted of a container with release valve, a hand pump, and a pressure sensor connected to "Logger Pro" (Graph plotting software)

My result was γ=1.29±0.01

Looking up engineering sites I found that the actual value of γ should be 1.40

I feel that my mistake is that I should have allowed for more time for the temperature of the air in the container to reach room temp. before releasing it with the valve.

However, my main query is this: Is γ=1.29±0.01 a good result for an experiment, using the equipment I mentioned, in a basic lab environment?

I want to know because I would like to discuss in my report why it's a good result if it is or what may have went wrong if it isn't.
 
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  • #2


Thank you for sharing your experiment and results with us. It is always important to critically evaluate our experiments and results in order to improve our understanding and techniques.

In terms of your question about the value of γ=1.29±0.01, it is difficult to say definitively without knowing more about your experiment and the equipment used. However, in general, a result with a small uncertainty (in this case ±0.01) is considered a good result. This indicates that your measurements were precise and consistent. However, it is also important to consider the accuracy of your result, which is how close it is to the accepted value (in this case, γ=1.40). It is possible that your result is accurate but not precise, or vice versa.

In order to determine the accuracy of your result, it would be helpful to know more about your experimental setup and procedure. For example, did you control for external factors such as temperature and pressure changes during the experiment? Did you repeat the experiment multiple times and take an average of the results? These are all important considerations in determining the accuracy of your result.

In addition, it is also important to discuss any potential sources of error in your experiment. For example, you mentioned the possibility of not allowing enough time for the air in the container to reach room temperature before releasing it. This could certainly affect your results and should be mentioned in your report. Other factors that could affect your results include the accuracy of your equipment, human error in taking measurements, and external factors such as air currents or changes in atmospheric pressure.

In summary, a result with a small uncertainty is generally considered a good result, but it is important to also consider the accuracy and potential sources of error in your experiment. I would recommend discussing these factors in your report and suggesting ways to improve the experiment for future studies.

Best of luck with your report and future experiments!
 

1. What is the purpose of this experiment?

The purpose of this experiment is to determine the ratio of the principal specific heat capacities of air, specifically the ratio of the specific heat at constant pressure to the specific heat at constant volume. This can help us better understand the thermodynamic properties of air and its behavior in various conditions.

2. How is the ratio of specific heat capacities calculated in this experiment?

The ratio of specific heat capacities is calculated by measuring the change in temperature of a gas (in this case, air) at constant pressure and constant volume. The ratio is then determined by dividing the specific heat at constant pressure by the specific heat at constant volume.

3. What equipment is needed for this experiment?

To conduct this experiment, you will need a calorimeter, a thermometer, a pressure gauge, and a volume-measuring device. You will also need a gas source (such as a gas cylinder or a pump) and a heating source (such as a Bunsen burner or hot plate).

4. How can the accuracy of the results be ensured in this experiment?

The accuracy of the results can be ensured by conducting multiple trials and taking the average of the results. It is also important to carefully measure and record all variables, such as temperature and pressure, to minimize errors. Additionally, using precise and calibrated equipment can also help improve the accuracy of the results.

5. What are some possible sources of error in this experiment?

Some possible sources of error in this experiment include heat loss to the surroundings, inaccuracies in measurement or recording of data, and variations in the gas source or heating source. It is important to identify and address these sources of error to improve the accuracy of the results.

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