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Module 5: Newtonian world and astrophysics

The Newtonian world and astrophysics module is all taught in year 13 and forms the second half of Modelling Physics.  The topic builds on module 3: forces and motion from year 12 and it is essential for you to have a good grasp of these ideas first.


The Newtonian world and astrophysics module is split in to 5 sub-modules: 

5.1 Thermal Physics

5.1 Thermal Physics

Image by Armando Ascorve Morales

By the end of this topic you should be able to:


  • Define what is meant by thermal equilibrium

  • Understand that temperature can be measured in both Kelvin and degrees Celsius, with Kelvin being the absolute scale of temperature, and how to convert between these  

  • State the properties of particles in solids, liquids and gases, including; structure, movement, density and relative potential and kinetic energy

  • Describe Brownian motion and an experiment that demonstrates the principle.

  • Describe what is meant by internal energy and how this changes as substances are heated and change state in terms of changes to their kinetic and potential energy.

  • Describe how internal energy links to the idea of absolute zero and an experiment to estimate this using variation of gas temperature with pressure. 

  • Describe what is meant by specific heat capacity including an experiment to deduce this for a material and perform calculation to find this.

  • Describe what is meant by specific latent heat of fusion and vapourisation including an experiment to deduce this for a solid and liquid and perform calculations to find this. 

  • Describe what is meant by a mole of substance and convert to number of particles using Avogadro's constant

  • Describe the assumptions underpinning the kinetic theory of gases. 

  • Describe how gas pressure is caused according to the kinetic theory

  • Explain the relationship between pressure and volume (Boyle's law) and pressure and temperature including how to experimentally investigate this. And use the equation of state of an ideal gas linking pressure, volume and temperature

  • Describe what is meant by root mean square (r.m.s) speed and mean square speed of particles in a gas and use the equation linking pressure, volume, number of particles and the mean square speed 

  • Describe the Boltzmann constant and use this in the derivation of the equation linking kinetic energy of particles to temperature. 

5.2 Circular motion
Image by Kinson Leung

5.2 Circular motion 

By the end of this topic you should be able to:​

  • Define what is meant by a radian and be able to complete calculations using these 

  • Describe period and frequency for objects in circular motion

  • Describe and calculate angular velocity

  • Describe why objects travel in circular motion

  • Calculate the speed of objects in circular motion and describe the factors that affect this

  • Describe and calculate centripetal acceleration

  • Describe and calculate centripetal force

  • Describe an experiment to investigate circular motion of a whirling bung

5.3 Oscillations

5.3 Oscillations

Image by Anthony DELANOIX

By the end of this topic you should be able to:​

  • Define the terms displacement, amplitude, period, frequency, angular frequency and phase difference in terms of oscillations

  • Define simple harmonic motion using the defining equation

  • Describe techniques and procedures used to determine period and frequency of simple harmonic oscillations

  • Perform calculations to find displacement and velocity of an object undergoing oscillations

  • Show graphically the variation in displacement, velocity and acceleration during simple harmonic motion

  • Describe how potential and kinetic energy changes during simple harmonic motion

  • Describe the effect of damping on an oscillatory system

  • Describe what is meant by resonance and how this links to natural frequency, including examples 

5.4 Gravitational fields
Image by Filipe Dos Santos Mendes

5.4 Gravitational fields

By the end of this topic you should be able to:

  • Draw gravitational fields around point masses and on a flat surface

  • Define what is meant by gravitational field strength 

  • Define and use Newton’s law of gravitation between two point masses

  • Describe Kepler’s three laws of planetary motion

  • Derive the equation form of Kepler’s third law relating period and radius of an orbit

  • Describe different types of satellite orbit

  • Describe what is meant by gravitational potential and calculate this

  • Describe what is meant by gravitational potential energy and calculate this

  • Define escape velocity and be able to calculate this

5.5 Astrophysics

5.5 Astrophysics

Image by NASA

By the end of this topic you should be able to:​

  • Describe components of the universe: planets, comets, solar systems, galaxies and the universe

  • Describe the formation and evolution of stars

  • Describe features of the Hertzsprung-Russell diagram 

  • Link energy levels in atoms to absorption and emission lines and be able to equate change in energy levels to a specific wavelength

  • Describe how diffraction gratings can be used to determine the wavelength of light and calculate the wavelength

  • Describe and use Wein’s law linking wavelength and temperature 

  • Describe and use Stefan’s law linking temperature, size and luminosity

  • Describe the units used to measure astronomical distances including the Astronomical Unit (AU), light year (ly) and parsec (pc) 

  • Define and describe the cosmological principle

  • Describe the Doppler effect and use this to measure the speed of recession of galaxies

  • Describe Hubble’s law and use this to be able to estimate the age of the universe including from graphical data

  • Explain evidence for the big bang theory including cosmic microwave background radiation

  • Describe the evolution of the universe

  • Describe theories of dark matter and dark energy

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