6.2.6
Molecular Kinetic Theory Model
Brownian Motion
Brownian Motion
Brownian motion was the first direct evidence of atoms.
Robert Brown
Robert Brown
- Robert Brown noticed that tiny pollen grains suspended in still water moved about in random paths.
- The pollen would change direction without colliding with other pollen grains.
- This can be observed with a microscope for any small particles in a fluid.
Atoms
Atoms
- The random motion of the pollen grains is caused by atoms randomly colliding with pollen in the fluid.
- This is direct evidence of atoms existing.
Pressure of an Ideal Gas
Pressure of an Ideal Gas
The pressure of an ideal gas is closely related to the temperature and volume.
Pressure
Pressure
- The pressure from a gas comes from molecules colliding with the wall of a container.
- Pressure can be increased by:
- Increasing concentration - collisions between molecules are more frequent if the molecules are packed together more tightly.
- Increasing temperature - hot gases have more kinetic energy and so more collisions will happen.
- Decreasing container size - this will increase the number of collisions.
Temperature and volume
Temperature and volume
- Pressure is linked to temperature and volume.
- Consider pumping up an empty car tire.
- Initially, the temperature will remain the same as the volume increases from a small increase in pressure.
- Next, the pressure will increase a lot as the volume refuses to expand more.
- Finally, the temperature will increase as the car is driven, this will increase the pressure.
1Measurements & Errors
2Particles & Radiation
2.1Particles
2.1.1Atomic Model
2.1.2Specific Charge, Protons & Neutron Numbers
2.1.3End of Topic Test - Atomic Model
2.1.4Isotopes
2.1.5Stable & Unstable Nuclei
2.1.6End of Topic Test - Isotopes & Nuclei
2.1.7A-A* (AO3/4) - Stable & Unstable Nuclei
2.1.8Particles, Antiparticles & Photons
2.1.9Particle Interactions
2.1.10Classification of Particles
2.1.11End of Topic Test - Particles & Interactions
2.1.12Quarks & Antiquarks
2.1.13Application of Conservation Laws
2.1.14End of Topic Test - Leptons & Quarks
2.1.15Exam-Style Question - Radioactive Decay
2.2Electromagnetic Radiation & Quantum Phenomena
3Waves
3.1Progressive & Stationary Waves
3.2Refraction, Diffraction & Interference
4Mechanics & Materials
4.1Force, Energy & Momentum
4.1.1Scalars & Vectors
4.1.2Vector Problems
4.1.3End of Topic Test - Scalars & Vectors
4.1.4Moments
4.1.5Centre of Mass
4.1.6End of Topic Test - Moments & Centre of Mass
4.1.7Motion in a Straight Line
4.1.8Graphs of Motion
4.1.9Bouncing Ball Example
4.1.10End of Topic Test - Motion in a Straight Line
4.1.11Acceleration Due to Gravity
4.1.12Projectile Motion
4.1.13Friction
4.1.14Terminal Speed
4.1.15End of Topic Test - Acceleration Due to Gravity
4.1.16Newton's Laws
4.1.17Momentum
4.1.18Momentum 2
4.1.19End of Topic Test - Newton's Laws & Momentum
4.1.20A-A* (AO3/4) - Newton's Third Law
4.1.21Work & Energy
4.1.22Power & Efficiency
4.1.23Conservation of Energy
4.1.24End of Topic Test - Work, Energy & Power
4.1.25Exam-Style Question - Forces
5Electricity
5.1Current Electricity
5.1.1Basics of Electricity
5.1.2Current-Voltage Characteristics
5.1.3End of Topic Test - Basics of Electricity
5.1.4Resistivity
5.1.5Superconductivity
5.1.6A-A* (AO3/4) - Superconductivity
5.1.7End of Topic Test - Resistivity & Superconductors
5.1.8Circuits
5.1.9Power and Conservation
5.1.10Potential Divider
5.1.11Emf & Internal Resistance
5.1.12End of Topic Test - Power & Potential
5.1.13Exam-Style Question - Resistance
6Further Mechanics & Thermal Physics (A2 only)
6.1Periodic Motion (A2 only)
6.2Thermal Physics (A2 only)
7Fields & Their Consequences (A2 only)
7.1Fields (A2 only)
7.2Gravitational Fields (A2 only)
7.3Electric Fields (A2 only)
7.4Capacitance (A2 only)
7.5Magnetic Fields (A2 only)
7.5.1Magnetic Flux Density
7.5.2End of Topic Test - Capacitance & Flux Density
7.5.3Moving Charges in a Magnetic Field
7.5.4Magnetic Flux & Flux Linkage
7.5.5Electromagnetic Induction
7.5.6Electromagnetic Induction 2
7.5.7Alternating Currents
7.5.8Operation of a Transformer
7.5.9Magnetic Flux Density
7.5.10End of Topic Test - Electromagnetic Induction
8Nuclear Physics (A2 only)
8.1Radioactivity (A2 only)
8.1.1Rutherford Scattering
8.1.2Alpha & Beta Radiation
8.1.3Gamma Radiation
8.1.4Radioactive Decay
8.1.5Half Life
8.1.6End of Topic Test - Radioactivity
8.1.7Nuclear Instability
8.1.8Nuclear Radius
8.1.9Mass & Energy
8.1.10Binding Energy
8.1.11Induced Fission
8.1.12Safety Aspects of Nuclear Reactors
8.1.13End of Topic Test - Nuclear Physics
8.1.14A-A* (AO3/4) - Nuclear Fusion
9Option: Astrophysics (A2 only)
9.1Telescopes (A2 only)
9.2Classification of Stars (A2 only)
9.3Cosmology (A2 only)
10Option: Medical Physics (A2 only)
10.1Physics of the Eye (A2 only)
10.2Physics of the Ear (A2 only)
10.3Biological Measurement (A2 only)
10.4Non-Ionising Imaging (A2 only)
10.5X-Ray Imaging (A2 only)
10.6Radionuclide Imaging & Therapy (A2 only)
11Option: Engineering Physics (A2 only)
11.1Rotational Dynamics (A2 only)
11.2Thermodynamics & Engines (A2 only)
12Option: Turning Points in Physics (A2 only)
12.1Discovery of the Electron (A2 only)
12.2Wave-Particle Duality (A2 only)
Jump to other topics
1Measurements & Errors
2Particles & Radiation
2.1Particles
2.1.1Atomic Model
2.1.2Specific Charge, Protons & Neutron Numbers
2.1.3End of Topic Test - Atomic Model
2.1.4Isotopes
2.1.5Stable & Unstable Nuclei
2.1.6End of Topic Test - Isotopes & Nuclei
2.1.7A-A* (AO3/4) - Stable & Unstable Nuclei
2.1.8Particles, Antiparticles & Photons
2.1.9Particle Interactions
2.1.10Classification of Particles
2.1.11End of Topic Test - Particles & Interactions
2.1.12Quarks & Antiquarks
2.1.13Application of Conservation Laws
2.1.14End of Topic Test - Leptons & Quarks
2.1.15Exam-Style Question - Radioactive Decay
2.2Electromagnetic Radiation & Quantum Phenomena
3Waves
3.1Progressive & Stationary Waves
3.2Refraction, Diffraction & Interference
4Mechanics & Materials
4.1Force, Energy & Momentum
4.1.1Scalars & Vectors
4.1.2Vector Problems
4.1.3End of Topic Test - Scalars & Vectors
4.1.4Moments
4.1.5Centre of Mass
4.1.6End of Topic Test - Moments & Centre of Mass
4.1.7Motion in a Straight Line
4.1.8Graphs of Motion
4.1.9Bouncing Ball Example
4.1.10End of Topic Test - Motion in a Straight Line
4.1.11Acceleration Due to Gravity
4.1.12Projectile Motion
4.1.13Friction
4.1.14Terminal Speed
4.1.15End of Topic Test - Acceleration Due to Gravity
4.1.16Newton's Laws
4.1.17Momentum
4.1.18Momentum 2
4.1.19End of Topic Test - Newton's Laws & Momentum
4.1.20A-A* (AO3/4) - Newton's Third Law
4.1.21Work & Energy
4.1.22Power & Efficiency
4.1.23Conservation of Energy
4.1.24End of Topic Test - Work, Energy & Power
4.1.25Exam-Style Question - Forces
5Electricity
5.1Current Electricity
5.1.1Basics of Electricity
5.1.2Current-Voltage Characteristics
5.1.3End of Topic Test - Basics of Electricity
5.1.4Resistivity
5.1.5Superconductivity
5.1.6A-A* (AO3/4) - Superconductivity
5.1.7End of Topic Test - Resistivity & Superconductors
5.1.8Circuits
5.1.9Power and Conservation
5.1.10Potential Divider
5.1.11Emf & Internal Resistance
5.1.12End of Topic Test - Power & Potential
5.1.13Exam-Style Question - Resistance
6Further Mechanics & Thermal Physics (A2 only)
6.1Periodic Motion (A2 only)
6.2Thermal Physics (A2 only)
7Fields & Their Consequences (A2 only)
7.1Fields (A2 only)
7.2Gravitational Fields (A2 only)
7.3Electric Fields (A2 only)
7.4Capacitance (A2 only)
7.5Magnetic Fields (A2 only)
7.5.1Magnetic Flux Density
7.5.2End of Topic Test - Capacitance & Flux Density
7.5.3Moving Charges in a Magnetic Field
7.5.4Magnetic Flux & Flux Linkage
7.5.5Electromagnetic Induction
7.5.6Electromagnetic Induction 2
7.5.7Alternating Currents
7.5.8Operation of a Transformer
7.5.9Magnetic Flux Density
7.5.10End of Topic Test - Electromagnetic Induction
8Nuclear Physics (A2 only)
8.1Radioactivity (A2 only)
8.1.1Rutherford Scattering
8.1.2Alpha & Beta Radiation
8.1.3Gamma Radiation
8.1.4Radioactive Decay
8.1.5Half Life
8.1.6End of Topic Test - Radioactivity
8.1.7Nuclear Instability
8.1.8Nuclear Radius
8.1.9Mass & Energy
8.1.10Binding Energy
8.1.11Induced Fission
8.1.12Safety Aspects of Nuclear Reactors
8.1.13End of Topic Test - Nuclear Physics
8.1.14A-A* (AO3/4) - Nuclear Fusion
9Option: Astrophysics (A2 only)
9.1Telescopes (A2 only)
9.2Classification of Stars (A2 only)
9.3Cosmology (A2 only)
10Option: Medical Physics (A2 only)
10.1Physics of the Eye (A2 only)
10.2Physics of the Ear (A2 only)
10.3Biological Measurement (A2 only)
10.4Non-Ionising Imaging (A2 only)
10.5X-Ray Imaging (A2 only)
10.6Radionuclide Imaging & Therapy (A2 only)
11Option: Engineering Physics (A2 only)
11.1Rotational Dynamics (A2 only)
11.2Thermodynamics & Engines (A2 only)
12Option: Turning Points in Physics (A2 only)
12.1Discovery of the Electron (A2 only)
12.2Wave-Particle Duality (A2 only)
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