7.1.5
Boyle's Law & Charles' Law
Investigation of Boyle's Law
Investigation of Boyle's Law
Boyle’s Law describes the relationship between the pressure and volume of a fixed mass of gas at constant temperature.


Manometer method
Manometer method
- Use a pump to change the air pressure on one side of the manometer.
- Use a pressure gauge on the pump side to measure air pressure, which is equal to the pressure of the air in the glass tube.
- You can measure the volume of trapped air.
- Record the volume for several different pressure values.


Analysis of manometer method
Analysis of manometer method
- If you plot a graph of volume against pressure, you get a monotonically decreasing curve.
- Plot a graph of V-1 against P and the best fit straight line goes through the origin.
- This verifies that V-1 is directly proportional to the pressure, i.e. pV is a constant or that P and V are inversely proportional to each other. This assumes that the temperature and mass of the gas is constant.


Further analysis of manometer method
Further analysis of manometer method
- You can use a logarithmic plot.
- Plot log(V) against log (P). It doesn’t matter what base logarithm you use.
- The gradient of the line of best fit should be -1.
- Assume V = k/P where k is a constant.
- log(V) = log(k) - log(P).
- log(V) = - log(P) + log(k).


Further analysis of manometer method 2
Further analysis of manometer method 2
- Compare the last line with y = mx + c.
- If log(V) is plotted on the y-axis, with log(P) on the x-axis, the gradient = -1 and the y-intercept should be log(k).
- You can find the constant, k, using k = Zc, where Z is the base of the logarithms (i.e. 10 or e) and c is the y-intercept.
Investigation of Boyle's Law 2
Investigation of Boyle's Law 2
Boyle’s Law describes the relationship between the pressure and volume of a fixed mass of gas at constant temperature.


Syringe and data logging method
Syringe and data logging method
- Connect the open end of a syringe to a pressure sensor (which is then connected to data logger and computer).
- Start recording on data logger.
- Move the plunger in steps, i.e. decrease or increase the volume of trapped gas slowly so as not to warm or cool the gas.
- For each new volume, record the pressure.


Syringe and data logging method 2
Syringe and data logging method 2
- Use software, such as a spreadsheet, to plot a graph of volume against pressure to get a monotonically decreasing curve.
- Use software to plot a graph of V-1 against P.
- The best fit straight line should go through the origin, verifying that V-1 is directly proportional to P.
- i.e. PV = constant or that P and V are inversely proportional to each other, assuming that the temperature and mass of the gas is constant.
Investigation of Charles’ Law
Investigation of Charles’ Law
Charles’ Law describes the relationship between the volume and absolute temperature of a fixed mass of gas at constant pressure.


Apparatus
Apparatus
- Set up the apparatus as shown in the diagram.
- Caution: it is common practice to use a kerosene-based oil, which needed a separate risk assessment because it is available via CLEAPPS.


Method
Method
- Keep stirring the water so as to reduce temperature gradients through the water.
- The length of the air column is directly proportional to the volume of trapped air. This assumes that the inner diameter of the capillary tube is constant.


Analysis
Analysis
- Plot a graph of the length of air column against temperature on a graph with axes as shown in the diagram.
- I.e. extended back to -400 °C so that an extrapolation back to the temperature axis can give a value for absolute zero.
- Notice that the values of volume and temperature are all bunched to the right.


Analysis 2
Analysis 2
- The extrapolation is suspect because you have to extrapolate a long way before the line hits the temperature axis.
- Repeating this with different gases, different volumes of gas and at different pressures gives different straight lines. All of the best fit straight lines should pass through the same point on the temperature axis.


Plot the graph again
Plot the graph again
- If you plot the graph again using the student’s value for absolute zero, the length-temperature graph becomes a straight line through the origin as shown.
- This shows that the volume of gas is directly proportional to the temperature in Kelvin. This assumes that the pressure and mass of the gas are constant.
1Physical Quantities & Units
2Measurement Techniques
3Kinematics
4Dynamics
4.1Momentum & Newton's Laws of Motion
4.2Non-Uniform Motion
4.3Linear Momentum & Conservation
4.4Force, Density & Pressure
4.4.1Fields
4.4.2Force in Uniform Fields
4.4.3Friction
4.4.4Buoyancy
4.4.5Terminal Speed
4.4.6End of Topic Test - Acceleration Due to Gravity
4.4.7Centre of Mass
4.4.8Forces & Equilibrium
4.4.9End of Topic Test - Scalars & Vectors
4.4.10Moments
4.4.11End of Topic Test - Moments & Centre of Mass
4.4.12Density
4.4.13Pressure
4.5Work, Energy & Power
5Gravitational Fields
5.1Gravitational Fields (A2 only)
6Deformation of Solids
7Thermal Physics
7.1Thermal Physics
7.1.1Temperature
7.1.2Measuring Temperature
7.1.3Ideal Gas Law
7.1.4Ideal Gases
7.1.5Boyle's Law & Charles' Law
7.1.6Molecular Kinetic Theory Model
7.1.7Molecular Kinetic Theory Model 2
7.1.8Thermal Energy Transfer
7.1.9Thermal Energy Transfer Experiments
7.1.10End of Topic Test - Thermal Energy & Ideal Gases
7.1.11First Law of Thermodynamics
8Oscillations
8.1Simple Harmonic Motion
8.2Waves
8.2.1Progressive Waves
8.2.2Intensity of Waves
8.2.3Wave Speed & Phase Difference
8.2.4Longitudinal & Transverse Waves
8.2.5End of Topic Test - Progressive Waves
8.2.6Electromagnetic Waves
8.2.7Doppler Effect
8.2.8Sound Waves
8.2.9Measuring Sound Waves
8.2.10End of Topic Test - Waves
8.2.11Ultrasound Imaging
8.2.12Ultrasound Imaging 2
9Communication
9.1Communication Channels
9.2Digital Communication
10Electric Fields
10.1Electric Fields
11Current Electricity
11.1Current Electricity
11.1.1Basics of Electricity
11.1.2Mean Drift Velocity
11.1.3Current-Voltage Characteristics
11.1.4End of Topic Test - Basics of Electricity
11.1.5Resistivity
11.1.6End of Topic Test - Resistivity & Superconductors
11.1.7Power and Conservation
11.1.8Microphones
11.1.9Components
11.1.10Relays
11.1.11Strain Gauges
12Magnetic Fields
12.1Magnetic Fields
13Modern Physics
13.1Quantum Physics
13.1.1The Photoelectric Effect
13.1.2The Photoelectric Effect Explanation
13.1.3End of Topic Test - The Photoelectric Effect
13.1.4Collisions of Electrons with Atoms
13.1.5Energy Levels & Photon Emission
13.1.6Wave-Particle Duality
13.1.7End of Topic Test - Absorption & Emission
13.1.8Band Theory
13.1.9Diagnostic X-Rays
13.1.10X-Ray Image Processing
13.1.11Absorption of X-Rays
13.1.12CT Scanners
13.2Nuclear Physics
13.2.1Rutherford Scattering
13.2.2Atomic Model
13.2.3Isotopes
13.2.4Stable & Unstable Nuclei
13.2.5A-A* (AO3/4) - Stable & Unstable Nuclei
13.2.6Alpha & Beta Radiation
13.2.7Gamma Radiation
13.2.8Particles, Antiparticles & Photons
13.2.9Quarks & Antiquarks
13.2.10Particle Interactions
13.2.11Radioactive Decay
13.2.12Half Life
13.2.13End of Topic Test - Radioactivity
13.2.14Nuclear Instability
13.2.15Mass & Energy
13.2.16Binding Energy
13.2.17A-A* (AO3/4) - Nuclear Fusion
Jump to other topics
1Physical Quantities & Units
2Measurement Techniques
3Kinematics
4Dynamics
4.1Momentum & Newton's Laws of Motion
4.2Non-Uniform Motion
4.3Linear Momentum & Conservation
4.4Force, Density & Pressure
4.4.1Fields
4.4.2Force in Uniform Fields
4.4.3Friction
4.4.4Buoyancy
4.4.5Terminal Speed
4.4.6End of Topic Test - Acceleration Due to Gravity
4.4.7Centre of Mass
4.4.8Forces & Equilibrium
4.4.9End of Topic Test - Scalars & Vectors
4.4.10Moments
4.4.11End of Topic Test - Moments & Centre of Mass
4.4.12Density
4.4.13Pressure
4.5Work, Energy & Power
5Gravitational Fields
5.1Gravitational Fields (A2 only)
6Deformation of Solids
7Thermal Physics
7.1Thermal Physics
7.1.1Temperature
7.1.2Measuring Temperature
7.1.3Ideal Gas Law
7.1.4Ideal Gases
7.1.5Boyle's Law & Charles' Law
7.1.6Molecular Kinetic Theory Model
7.1.7Molecular Kinetic Theory Model 2
7.1.8Thermal Energy Transfer
7.1.9Thermal Energy Transfer Experiments
7.1.10End of Topic Test - Thermal Energy & Ideal Gases
7.1.11First Law of Thermodynamics
8Oscillations
8.1Simple Harmonic Motion
8.2Waves
8.2.1Progressive Waves
8.2.2Intensity of Waves
8.2.3Wave Speed & Phase Difference
8.2.4Longitudinal & Transverse Waves
8.2.5End of Topic Test - Progressive Waves
8.2.6Electromagnetic Waves
8.2.7Doppler Effect
8.2.8Sound Waves
8.2.9Measuring Sound Waves
8.2.10End of Topic Test - Waves
8.2.11Ultrasound Imaging
8.2.12Ultrasound Imaging 2
9Communication
9.1Communication Channels
9.2Digital Communication
10Electric Fields
10.1Electric Fields
11Current Electricity
11.1Current Electricity
11.1.1Basics of Electricity
11.1.2Mean Drift Velocity
11.1.3Current-Voltage Characteristics
11.1.4End of Topic Test - Basics of Electricity
11.1.5Resistivity
11.1.6End of Topic Test - Resistivity & Superconductors
11.1.7Power and Conservation
11.1.8Microphones
11.1.9Components
11.1.10Relays
11.1.11Strain Gauges
12Magnetic Fields
12.1Magnetic Fields
13Modern Physics
13.1Quantum Physics
13.1.1The Photoelectric Effect
13.1.2The Photoelectric Effect Explanation
13.1.3End of Topic Test - The Photoelectric Effect
13.1.4Collisions of Electrons with Atoms
13.1.5Energy Levels & Photon Emission
13.1.6Wave-Particle Duality
13.1.7End of Topic Test - Absorption & Emission
13.1.8Band Theory
13.1.9Diagnostic X-Rays
13.1.10X-Ray Image Processing
13.1.11Absorption of X-Rays
13.1.12CT Scanners
13.2Nuclear Physics
13.2.1Rutherford Scattering
13.2.2Atomic Model
13.2.3Isotopes
13.2.4Stable & Unstable Nuclei
13.2.5A-A* (AO3/4) - Stable & Unstable Nuclei
13.2.6Alpha & Beta Radiation
13.2.7Gamma Radiation
13.2.8Particles, Antiparticles & Photons
13.2.9Quarks & Antiquarks
13.2.10Particle Interactions
13.2.11Radioactive Decay
13.2.12Half Life
13.2.13End of Topic Test - Radioactivity
13.2.14Nuclear Instability
13.2.15Mass & Energy
13.2.16Binding Energy
13.2.17A-A* (AO3/4) - Nuclear Fusion
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