OCR A-Level Physics
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Development of practical skills in physics
Practical skills assessed in a written examination
1.1.1 - Planning experimentsDesign experiments that turn a physical question into measurable evidence. Choose variables, apparatus, a useful range and a method of analysis, then check whether the plan can answer the question safely.
1.1.2 - Implementing experimentsCarry out measurements correctly and keep a usable scientific record. Learn how to check apparatus, record raw readings with suitable units and precision, and distinguish measurements from observations and corrected values.
1.1.3 - Analysing experimental dataExperimental physics does not finish when the apparatus is switched off. The readings have to be processed, displayed, and interpreted so that a conclusion follows from the evidence rather than from wishful thinking. In this lesson you will practise the OCR analysis skills behind almost every pra...
1.1.4 - Evaluating experimentsEvaluation is the skill of deciding how much trust to place in experimental evidence. In this lesson you will learn how to draw conclusions from data, identify anomalies and limitations, judge precision and accuracy using uncertainties, and suggest improvements that genuinely make an investigatio...
Practical skills assessed in the practical endorsement
1.2.1 - Practical endorsement skillsPractical physics is not just a set of demonstrations that happen beside the "real" course. Practical skill is part of the qualification: it supports the written papers and is also assessed directly through the Practical Endorsement. This lesson teaches the broad conduct skills in section 1.2.1:...
1.2.2(a)-(e) - Measurement apparatus and accuracyIn this lesson you learn how the specification expects you to choose and use basic measuring apparatus. The focus is not just naming the instrument: it is reading it properly, reducing avoidable error, and explaining why one method gives a better measurement than another. These skills appear thro...
1.2.2(f)-(j) - Circuits and wave apparatusThis lesson is about using electrical and wave apparatus well enough to collect trustworthy data. These skills can be assessed inside later electricity, waves, superposition and optics questions, so the aim here is practical competence: connect the apparatus correctly, choose sensible ranges, rea...
1.2.2(k)-(l) - ICT, data logging and ionising radiationThis lesson is about using modern practical tools well: data loggers, sensors, software, computer models and radiation detectors. These can be assessed as practical techniques, so the skill is not just naming equipment. You need to explain why a tool is suitable, how to set it up, how to process...
Foundations of physics
Physical quantities and units
2.1.1 - Physical quantitiesPhysics turns observations into quantities that can be compared, calculated with, and checked. In this lesson you will learn what makes a physical quantity complete, why the unit matters as much as the number, and how to make sensible estimates rather than unsupported guesses. This is a small spe...
2.1.2 - SI units, prefixes and graph labelsPhysics answers only communicate clearly when the quantity, number and unit travel together. In this lesson you will use the S.I. base quantities named in this specification, build derived units from them, check whether equations are homogeneous, convert prefixes, and label tables and graph axes...
Making measurements and analysing data
Forces and motion
Motion
3.1.1 - Kinematics and motion graphsMotion is easier to analyse when you can move between words, equations and graphs. In this lesson you will define the main kinematics quantities, interpret displacement-time and velocity-time graphs, and use gradients and areas to extract physical information. These skills are also practical skil...
3.1.2(a)(i) - Constant-acceleration equationsConstant acceleration is one of the most useful ideal models in mechanics. In this lesson you will connect the four constant-acceleration equations to a straight-line velocity-time graph, choose the right equation from the quantities in a problem, and apply the same model to vertical free fall wh...
3.1.2(a)(ii),(b) - Motion and free-fall investigationsMotion experiments turn a moving object into measurements: distances, times, speeds and accelerations. In this lesson you will compare common laboratory techniques for investigating motion, then use two practical routes to determine the acceleration of free fall, g. The physics is familiar, b...
3.1.2(c) - Reaction time and stopping distancesStopping a vehicle is not one instant. There is a short time while the driver responds, then a separate interval while the brakes reduce the vehicle's speed to zero. In this lesson you will connect reaction time, thinking distance, braking distance and stopping distance, and use those ideas in OC...
3.1.3 - Projectile motionProjectile motion is two-dimensional motion where gravity changes the vertical motion while the horizontal motion continues independently. In this lesson you will learn how to split one flight into two simpler one-dimensional motions, choose the right equation for each direction, and recombine th...
Forces in action
3.2.1 - Dynamics and free-body diagramsDynamics links forces to motion. In this lesson you will learn how to model forces on an object, draw free-body diagrams, use F = ma and W = mg, and handle one- and two-dimensional motion when the resultant force is constant. The skill is not just substituting into equations: it is choosi...
3.2.2 - Drag and terminal velocityObjects rarely fall exactly like the constant-acceleration examples from earlier kinematics. As soon as an object moves through air, oil, water or any other fluid, it experiences drag, so the resultant force and acceleration change during the motion. In this lesson you will learn how drag changes...
3.2.3(a)-(d) - Moments, couples and centres of massForces can make objects move in a straight line, but they can also make extended objects turn. In this lesson you will learn how to calculate the turning effect of a force, how a couple produces a pure turning effect, and how moments explain the position of an object's centre of gravity. The fina...
3.2.3(e)-(f) - Equilibrium and triangle of forcesEquilibrium is the physics word for a situation where forces do not make an object accelerate and torques do not make it start rotating. In this lesson you will learn the two checks for equilibrium, then use a triangle of forces for three coplanar forces. The aim is to make force diagrams useful:...
3.2.4 - Density, pressure and upthrustDensity tells you how much mass is packed into a volume. Pressure tells you how a force is spread over an area. In fluids, these ideas combine: pressure increases with depth, and the pressure difference around an object produces upthrust. By the end of this lesson, you should be able to use the e...
Work, energy and power
3.3.1 - Work and conservation of energyWork, energy and power are everyday words, but in physics they have precise meanings. In this lesson you will learn what it means for a force to do work, why the angle of the force matters, and how work links directly to energy transfer. You will also practise the energy-accounting language neede...
3.3.2 - Kinetic and gravitational potential energyEnergy calculations are most useful when they let you replace a messy force-and-motion story with a cleaner account of what has been transferred. In this lesson you will learn the two energy equations you must recall, derive them from work and motion ideas, and use them to follow the exchange bet...
3.3.3 - Power and efficiencyPower tells you how quickly work is done or energy is transferred. Efficiency tells you what fraction of the input energy becomes useful output energy. In this lesson you will connect those ideas to moving systems, derive P = Fv from first principles, and judge mechanical systems using clear...
Materials
3.4.1 - Springs and Hooke's lawSprings are useful because their deformation can be measured and modelled. In this lesson you will distinguish extension from total length, use Hooke's law in the form F = kx, interpret force-extension graphs, and describe a practical method for investigating springs, wires, rubber bands and...
3.4.2(a)-(d) - Elastic energy, stress and Young modulusStretching a wire is not just a visible change in length. It lets you measure work done, stored elastic energy, stress, strain, and the stiffness of the material itself. In this lesson you will connect force-extension graphs to energy, then use stress and strain to define and determine the Young...
3.4.2(e)-(f) - Material behaviour and deformationStress-strain graphs let you compare materials without being distracted by the exact size of the sample. In this lesson you will read typical stress-strain graphs for ductile, brittle and polymeric materials, then use unloading behaviour to distinguish elastic deformation from plastic deformation...
Newton's laws of motion and momentum
3.5.1(a)-(c) - Newton's laws and momentumForces do not just "make things move"; they change the motion of objects. In this lesson you will connect Newton's three laws to momentum, the quantity that combines mass and velocity. The central OCR idea is that resultant force is the rate of change of momentum, with F = ma as the constant-...
3.5.1(d)-(e) - Impulse and force-time graphsImpulse measures what a force does when it acts for a time. In this lesson you will learn how to calculate impulse for a constant force, connect impulse to change in momentum, and determine impulse from the area under a force-time graph. The graph skill is especially important when the force is n...
3.5.2 - Collisions and conservation of momentumCollisions are short interactions in which two or more bodies exchange momentum. In this lesson you will learn how to choose a collision system, apply conservation of momentum in one and two dimensions, and decide whether a collision is perfectly elastic or inelastic. The central habit is to keep...
Electrons, waves and photons
Charge and current
4.1.1 - Charge, current and Kirchhoff's first lawElectric circuits only make sense once charge is treated as something that is counted, transferred and conserved. In this lesson you will connect the coulomb, the elementary charge, electric current and Kirchhoff's first law into one model: charge can move, but it cannot vanish at a junction. Thi...
4.1.2 - Mean drift velocity and number densityA current in a wire looks continuous from the outside, but at microscopic level it is made from many charge carriers moving through a cross-section each second. In this lesson you will connect that microscopic picture to the OCR relationship I = Anev. You will also use number density n to...
Energy, power and resistance
4.2.1 - Circuit symbols and diagramsCircuit diagrams are the written language of electric circuits. In this lesson you will learn the common symbols used in OCR A Level Physics A, how to combine them into clear diagrams, and how to read what a diagram says about current paths and measuring instruments. The aim is not to calculate c...
4.2.2 - E.m.f., p.d. and energy transferCircuits are easier to understand when you track energy as well as charge. In this lesson you will define potential difference and e.m.f. using energy transferred per unit charge, use the volt as J C⁻¹, and calculate energy transfers with W = VQ and W = EQ. You will then...
4.2.3 - Resistance and I-V characteristicsResistance tells you how much potential difference is needed to drive a particular current through a component. In this lesson you will learn the recall equation for resistance, the precise condition in Ohm's law, the characteristic graph shapes for common components, and the practical method use...
4.2.4 - Resistivity and temperature dependenceResistance is not only about the component in front of you. A long thin wire has more resistance than a short thick wire of the same material, and different materials behave differently even with the same shape. In this lesson you will connect resistance to resistivity, use a metal-wire practical...
4.2.5 - Electrical power, energy and costElectrical power tells you how quickly electrical energy is transferred by a circuit component. In this lesson you will connect the circuit meaning of power to the equations in the data booklet, then use the same idea to calculate energy transfer and the cost of electrical energy. The main skill...
Electrical circuits
4.3.1 - Series, parallel and multi-source circuitsCircuit analysis is bookkeeping for charge and energy. In this lesson you will use Kirchhoff's laws to decide what must be the same, what must split, and how e.m.f.s and p.d.s balance in a loop. By the end, a mixed resistor network or a circuit with two sources should feel like a sequence of deci...
4.3.2 - Internal resistanceReal cells and power supplies do not give all their energy to the external circuit. In this lesson you will model a source of e.m.f. as an ideal source in series with an internal resistance, use the OCR relationships E = I(R + r) and E = V + Ir, and learn how internal resistance is determ...
4.3.3 - Potential dividers and sensorsPotential dividers turn a fixed input p.d. into a chosen output p.d. by sharing voltage between series components. In this lesson you will see why the sharing depends on resistance, how a potentiometer is just an adjustable divider, and how an LDR or thermistor converts a change in light or tempe...
Waves
4.4.1(a)-(e) - Wave quantities, graphs and equationsWaves let energy and information travel without a material object having to travel the whole distance. In this lesson you will learn the wave language OCR expects: the difference between progressive, transverse and longitudinal waves, how to read wave quantities from graphs and oscilloscope trace...
4.4.1(f)-(g) - Wave effects, polarisation and intensityWaves are useful because they behave in predictable ways when they meet a boundary, a gap, or a filter. In this lesson you will learn how to describe reflection, refraction, diffraction and polarisation, how to demonstrate these effects with OCR-style apparatus, and how intensity connects wave po...
4.4.2(a)-(c) - Electromagnetic spectrum and polarisationElectromagnetic waves include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays. In this lesson you will learn what all electromagnetic waves have in common, how to place the main regions of the spectrum on a wavelength scale, and how polarisation shows that ele...
4.4.2(d)-(e) - Refraction and total internal reflectionLight changes speed when it enters a different transparent material, and an obliquely incident ray can change direction as a result. In this lesson you will connect the physical idea of speed change to refractive index, Snell's law, critical angle and total internal reflection. You will also lear...
4.4.3(a)-(e) - Superposition, interference and coherenceWhen waves overlap, the medium does not have to choose which wave to follow. The displacements add, and that simple idea explains loud and quiet regions in two-speaker sound experiments, strong and weak microwave signals, and the conditions needed for a stable interference pattern. In this lesson...
4.4.3(f)-(g) - Young's double slit and diffraction gratingsThin slits can turn a beam of light into a measurement tool. In this lesson you will see why Young's double-slit experiment was classical evidence for the wave nature of light, how to use the fringe-spacing equation, and how a diffraction grating gives sharper angular maxima for wavelength measur...
4.4.4 - Stationary waves and harmonicsStationary waves explain why strings, microwave cavities and air columns can vibrate strongly only at certain frequencies. In this lesson you will learn how a stationary wave forms, how to identify nodes and antinodes, and how harmonic patterns fit inside strings and tubes. You will also use a re...
Quantum physics
4.5.1 - Photons, the Planck constant and electronvoltsLight has already behaved like a wave for interference, diffraction and polarisation. In this lesson the same electromagnetic radiation is modelled as arriving in packets of energy called photons. You will learn how photon energy depends on frequency and wavelength, why the electronvolt is a usef...
4.5.2 - The photoelectric effectThe photoelectric effect is one of the cleanest pieces of evidence that electromagnetic radiation can behave as photons. In this lesson you will connect a simple zinc-plate demonstration to the photon model, then use Einstein's photoelectric equation to calculate threshold frequency and maximum k...
4.5.3 - Wave-particle duality and electron diffractionElectrons are usually introduced as particles: they have charge, mass and can be accelerated through a potential difference. This lesson adds the other half of the quantum picture. Electron diffraction shows that particles can also behave like waves, and the de Broglie equation lets you calculate...
Newtonian world and astrophysics
Thermal physics
5.1.1 - Temperature and thermal equilibriumTemperature is more than a number on a thermometer. It tells us the direction in which thermal energy would be transferred, and a thermometer gives a reliable reading after its probe reaches thermal equilibrium with the object. In this lesson you will learn the OCR definitions and habits for ther...
5.1.2 - Kinetic model, internal energy and phase changeThermal physics becomes much easier once you can move between two pictures: what you see in the laboratory and what the atoms or molecules are doing. In this lesson you will use the kinetic model to explain solids, liquids, gases, Brownian motion, internal energy, absolute zero and why temperatur...
5.1.3 - Specific heat capacity and latent heatThermal energy can raise a temperature, or it can change the state of a substance while the temperature stays constant. In this lesson you will learn how to calculate both kinds of energy transfer, how to determine the relevant constants using electrical methods, and how OCR-style questions hide...
5.1.4(a)-(d) - Ideal gas model and gas experimentsIdeal gases give us a clean model for connecting microscopic particle motion to measurable quantities such as pressure, volume, temperature and amount of substance. In this lesson you will learn the assumptions behind the model, use the equation of state pV=nRT, and connect the equation to Bo...
5.1.4(e)-(i) - Kinetic theory of ideal gasesThe ideal gas equation pV = nRT connects pressure, volume, temperature and amount of substance. This lesson goes one layer deeper: it links those large-scale measurements to the random motion and kinetic energy of individual particles. You will use OCR's kinetic-theory equations, handle r.m.s...
Circular motion
5.2.1 + 5.2.2(b) - Circular kinematicsCircular motion is easier when you describe position by an angle instead of by separate horizontal and vertical coordinates. In this lesson you will meet the radian, connect period and frequency to one complete revolution, and use angular velocity to link rotational motion with ordinary tangentia...
5.2.2 - Centripetal acceleration and forceCircular motion looks familiar, but it is easy to misread the forces. In this lesson you will learn why an object moving at constant speed in a circle is still accelerating, how to calculate the inward acceleration and resultant force, and how the whirling-bung experiment tests the same relations...
Oscillations
5.3.1 - Simple harmonic motionSimple harmonic motion, or SHM, is the clean mathematical model behind many oscillations: a mass on a spring, a small-amplitude pendulum, a vibrating atom, or a carefully isolated air-track glider. In this lesson you will learn the kinematics OCR expects: the defining acceleration equation, the t...
5.3.2 - Energy in simple harmonic motionSimple harmonic motion is not only a repeated pattern of displacement, velocity and acceleration. It is also a repeated transfer of energy. In this lesson you will learn where the kinetic and potential energy are largest, how to derive the energy-displacement equations, and how to read the charac...
5.3.3 - Damping, forced oscillations and resonanceReal oscillators do not keep moving forever unless energy is supplied to them. In this lesson you will learn how damping removes energy from oscillating systems, how a periodic driving force can maintain an oscillation, and why resonance can make an apparently small driver produce a very large re...
Gravitational fields
5.4.1 - Gravitational fields and field strengthGravity is not just a force that appears when two objects touch. In this lesson you will learn how physicists describe the space around a mass using a gravitational field, how field lines map that field, and how gravitational field strength tells you the force per unit mass. The key equation is s...
5.4.2 - Newton's law of gravitationGravity is not just a force near the Earth's surface. Newton's law of gravitation models the attraction between any two masses, and it explains why the gravitational field gets weaker with distance. In this lesson you will use the inverse-square law, convert it into gravitational field strength,...
5.4.3 - Planetary motion and geostationary orbitsPlanets and satellites are not held up by an outward force. They are continually accelerating towards the body they orbit, with gravity providing the centripetal force. In this lesson you will connect Kepler's laws to Newton's law of gravitation, derive the orbital-period equation that OCR expect...
5.4.4 - Gravitational potential, energy and escape velocityGravitational fields store energy in a way that feels strange at first: the natural zero is not the ground, but infinity. In this lesson you will learn why gravitational potential and gravitational potential energy are negative near a planet, how force-distance graphs represent work done, and how...
Astrophysics and cosmology
5.5.1(a)-(f) - Star formation and evolutionStars are not permanent objects: they form when gravity collapses interstellar gas and dust, spend most of their lives balancing gravity with pressure, and end in different ways depending mainly on mass. In this lesson you will learn the OCR vocabulary for astronomical objects, then follow the ph...
5.5.1(g) - H-R diagram and stellar classificationThe Hertzsprung-Russell diagram, usually called the HR diagram, is a map for classifying stars using two measured properties: luminosity and surface temperature. In this lesson you will learn how to read the axes, recognise the main sequence, and identify red giants, red supergiants and white dwa...
5.5.2(a)-(h) - Spectra, energy levels and diffraction gratingsSpectra let astronomers turn starlight into evidence. In this lesson you will connect electron energy levels to photons, explain why atoms produce line spectra, and use a transmission diffraction grating to determine wavelengths. The same two ideas sit underneath much of stellar spectroscopy: ato...
5.5.2(i)-(k) - Wien's law, Stefan's law and stellar radiusStars are too far away for us to measure their sizes directly in the laboratory sense, but their light carries quantitative clues. In this lesson you will use the peak wavelength of a star's continuous spectrum to estimate its surface temperature, use Stefan's law to connect temperature, luminosi...
5.5.3(a)-(d) - Distances, parallax and the cosmological principleThe universe is too large for metres to be a comfortable everyday unit, so astronomers choose distance units that match the scale being described. In this lesson you will use the astronomical unit, light-year and parsec, then see how stellar parallax gives a direct distance method for nearby star...
5.5.3(e)-(i) - Redshift, Hubble's law and expansionGalaxies send us light that carries two linked messages: the pattern of spectral lines tells us what emitted the light, and the shift of those lines tells us how the source is moving relative to us. In this lesson you will use redshift to find recession speed, use Hubble's law to connect speed wi...
5.5.3(j)-(o) - Big Bang evidence, age and compositionThe Big Bang theory is not just a dramatic name for "the start". In this lesson you will learn how the model is supported by microwave background radiation, how the expansion rate gives a simple estimate for the age of the universe, and how physicists currently describe the universe's composition...
Particles and medical physics
Capacitors
6.1.1 - Capacitance and capacitor combinationsCapacitors store separated charge, so they bring charge, potential difference and circuit timing together. In this lesson you will define capacitance, describe how electrons move during charging and discharging, and calculate the total capacitance of series and parallel combinations. You will als...
6.1.2 - Energy stored in capacitorsA capacitor stores energy when charge has been separated onto its plates. In this lesson you will connect that stored energy to the area under a p.d.-charge graph, then use the three OCR capacitor-energy equations confidently. You will also see why capacitors are useful when energy must be stored...
6.1.3 - Capacitor charging and dischargingA capacitor charges and discharges at a changing rate because the potential difference across it changes the circuit current. This lesson explains exponential charge and discharge curves, calculations using the time constant, natural-logarithm plots, and spreadsheet models of discharge.
Electric fields
6.2.1 - Electric fields and field strengthElectric fields let us talk about how a charge can exert a force without touching another charge. In this lesson you will learn what an electric field is, how field lines map its direction and relative strength, why a uniformly charged sphere can be modelled as a point charge at its centre, and h...
6.2.2 - Coulomb's law and point-charge fieldsCharges do not need to touch to exert forces on each other. In this lesson you will learn how Coulomb's law gives the force between two point charges, how that leads to the electric field strength around a point charge, and why the pattern is an inverse-square field. You will also compare point-c...
6.2.3 - Uniform electric fields and parallel platesParallel plates are the cleanest place to meet a uniform electric field: the force per unit charge is almost the same everywhere between the plates, away from the edges. In this lesson you will connect the field strength to the p.d. and separation, use the parallel-plate capacitance formula with...
6.2.4 - Electric potential, energy and isolated spheresElectric potential lets you talk about energy in an electric field without carrying a particular test charge through every sentence. In this lesson you will define potential relative to infinity, use the point-charge potential equation, derive the capacitance of an isolated conducting sphere, and...
Electromagnetism
6.3.1 - Magnetic fields and force on a conductorMagnetic fields turn compass needles and exert forces on current-carrying wires. This lesson explains the field patterns around wires and coils, Fleming's left-hand rule for force direction, and how force depends on magnetic flux density, current, wire length and the angle to the field. It also s...
6.3.2 - Charged particles in magnetic fieldsA current-carrying wire is many moving charges at once; this lesson zooms in on one charged particle. You will calculate the magnetic force on a moving charge, explain why a uniform magnetic field can make a particle move in a circular path, and use crossed electric and magnetic fields as a veloc...
6.3.3(a)-(e) - Flux, Faraday's and Lenz's laws and generatorsElectromagnetic induction is how changing magnetic fields become measurable e.m.f.s. In this lesson you will define magnetic flux and flux linkage, use Faraday's law and Lenz's law, describe how search coils investigate changing flux, and explain the simple a.c. generator. The important OCR habit...
6.3.3(f) - TransformersTransformers are one of the most useful applications of electromagnetic induction: they transfer energy between two circuits without direct electrical contact. In this lesson you will learn how a laminated iron-cored transformer works, how to use the ideal-transformer equations, and how OCR expec...
Nuclear and particle physics
6.4.1 - The nuclear atom, radius and densityThe nuclear atom is a model built from evidence, not a picture someone simply guessed. In this lesson you will use alpha-particle scattering to explain why the atom has a tiny charged nucleus, then connect nuclear notation, the strong nuclear force, nuclear radius and density into one coherent mo...
6.4.2(a)-(g) - Particles, antiparticles, hadrons and leptonsParticle physics uses classification to keep a very small world tidy. In this lesson you will learn the principal particle–antiparticle pairs, separate hadrons from leptons by the forces they experience, and use the simple quark model to explain the proton and neutron. The main skill is charge ac...
6.4.2(h)-(l) - Quarks, beta decay and particle decayBeta decay is not just a nucleus changing its proton number; in the quark model, it is one quark inside a particle changing type. In this lesson you will use the u, d and s quark charges to write beta-minus and beta-plus decay equations, check charge conserv...
6.4.3(a)-(c) - Nuclear radiation and decay equationsRadioactive sources are useful because they emit ionising radiation, but the emission is not like a machine releasing one particle every second. In this lesson you will learn how alpha, beta and gamma radiation differ, how their absorption can be investigated safely, and how to balance nuclear de...
6.4.3(d)-(h) - Activity, half-life, decay and datingRadioactive decay is random for any one nucleus, but a large sample follows a very predictable pattern. In this lesson you will connect activity, decay constant, half-life and exponential decay equations, then use the same ideas in practical half-life measurement, spreadsheet models and radioacti...
6.4.4(a)-(f) - Mass-energy, binding energy and nuclear reactionsNuclear reactions are a place where a very small change in rest mass can correspond to a large amount of energy. In this lesson you will use Einstein's mass-energy equation, connect it to particle-antiparticle pairs, and calculate binding energy from masses. You will also learn how the binding-en...
6.4.4(g)-(k) - Fission, fusion and nuclear equationsFission reactors and fusion reactions both involve changes inside nuclei, not chemical rearrangements of atoms. In this lesson you will learn how a neutron can induce fission, how a reactor controls a chain reaction, why nuclear waste creates environmental decisions, why fusion needs very high te...
Medical imaging
6.5.1(a)-(d) - X-ray production and attenuationX-rays are useful because they are high-energy photons that can pass through some materials but are strongly reduced by others. In this lesson you will build the physics from the tube that makes the photons, through the interactions that remove them from a beam, to the exponential law OCR uses fo...
6.5.1(e)-(g) - X-ray imaging and CAT scansPlain X-ray images and CAT scans both use X-rays, but they answer different medical questions. In this lesson you will see how contrast media such as barium and iodine make selected structures stand out, how a CAT scanner builds slice images using a rotating X-ray beam and detectors, and why OCR...
6.5.2 - Gamma cameras, PET and medical tracersMedical tracers let doctors use nuclear physics to study how living tissue is working. In this lesson you will meet the two OCR tracer examples, follow the signal through a gamma camera, then see how PET turns positron-electron annihilation into a three-dimensional image. The important contrast i...
6.5.3 - Ultrasound imaging, impedance and DopplerUltrasound imaging turns reflected sound pulses into information about position, tissue boundaries and blood flow. In this lesson you will connect the wave physics to the scanner: how a transducer sends and receives pulses, why boundaries reflect some ultrasound, why gel matters, and how the Dopp...