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Explore air pressure and how it works. In a sealed syringe, as the plunger moves back and forth, the volume of air in the syringe changes. With a large enough syringe, a PocketLab can be placed inside to measure the change in pressure as the volume changes. MaterialsObjectiveIn this experiment, students will be able to:
Extension ObjectiveStudents will be able to
Hypothesis and Predictions
Procedure
Data Analysis and Observations
Conclusions
Optional Extension
Teacher’s GuideAllow students some time to play around with the syringe and PocketLab to intuitively find the relationship between volume and pressure before they record much data. They should still make their predictions first, as the relationships in the lab will become immediately apparent. Make sure they try sealing the syringe with their finger and pushing the plunger in as far as they can. The students will not only observe the graph change in real time, but they will also feel the pressure increase as the plunger will get harder and harder to push into the syringe. Make sure students are changing the volume by the same amount each time. It will be more difficult to find a linear relationship if the students aren’t changing the volume consistently (still possible, just more difficult). To find the linear equation (P=mV+b) between pressure, P, and volume, V, for the gas in the syringe, it may be easier for students to graph pressure versus volume and find the slope, m, and y-intercept, b, of the line to find the rate of change between the two variables and the starting point for pressure. For the extension, students may need a background in chemistry, or at least an understanding of moles to fully understand the Ideal Gas Law. However, the mathematical relationships between the variables are still accessible with Pre-Algebra/Algebra 1 skills. Pressure, P, and volume, V, are inversely proportional. Temperature, T, and pressure, P, are directly proportional, meaning temperature, T, and volume, V, are also directly proportional. Pressure, P, and volume, V, are directly proportional to the ideal/universal gas constant, R, and the amount of gas/moles, N. The resulting equation is PV = NRT.
Pressure and Volume with a Syringe.pdf 25th Dec 2019 @ 4 min read Boyle's law is a pressure versus volume relationship. The law was discovered by Robert Boyle in the 17th century. It states the pressure of a fixed amount of a gas is inversely proportional to its volume at a constant temperature. The law can be empirically proven. The article discusses an experimental method to verify the law using a syringe. Experiment: Sealed syringeThe experiment is very simple. It can be performed at home. When the tip of a syringe is sealed with a cap, the air inside the syringe is isolated from the atmosphere. This will fix the amount of the gas. The weights (books) are added upon the plunger of the syringe. It will push the plunger downwards; in other words, the air in the syringe is compressed. By recording the weights of the books added and the volume reading from the syringe, we can establish the pressure-volume relationship. ObjectiveTo verify Boyle's law and to plot the pressure-volume graph Materials
Nomenclature
Procedure
Precautions
ObservationThe initial weight (w0) is 92 g. The total weight is . The observation table is as follows:
CalculationThe pressure on the air inside the syringe is the pressure exerted by the weights plus atmospheric pressure. The pressure exerted by the weights is the force exerted by the weights divided the inner area of the syringe. Now, Force (Fw) is mass (Wi) times acceleration (a). Here, r is the inner radius of the syringe, which can be measured; r = 0.005 m. a is the acceleration due to gravity; a = 9.81 m s−2. For Wi = 92 g, Assume atmospheric pressure (Patm) as 101.325 kPa. Similarly, we can calculate the total pressure for the rest. The calculation table is as follows:
We have to plot the graph of Pi vs Vi and PiVi vs Vi. ResultsThe Pressure vs volume graph is as follows: Pressure vs volumeThe pressure-volume vs volume graph is as follows: Pressure-volume vs volumeConclusionThe PV curve from the above figure is satisfactory. As the pressure of the air increases, its volume decreases. The air obeys Boyle's law. Also, the product of pressure and volume approximately constant and its value is independent of volume or pressure. Also, check a laboratory method: To verify Boyle's law» Associated articles
Copy Article Cite "To Demonstrate Boyle's Law by Syringe Experiment" ChemistryGod, 25th Dec 2019, https://chemistrygod.com/demonstrate-boyle-lawThanks for your response!
Zephaniah Lapa Very helpful, Thankyou so much..
Henry Awesome! work, i like your examples, thank you sir. |