Prerequisites

The course assumes basic familiarity with performing experiments and the analysis of errors from the IA Physics practicals. One skill introduced briefly in IA that will be relied on heavily for the Michaelmas course is the use of PicoScopes, but this will be revised and expanded on in the first practical. There are elements of the course which use Python and Jupyter notebooks for data acquisition and analysis, and familiarity with the material from the IA Scientific Computing course will be assumed.

Learning Outcomes and Assessment

Learning Outcomes and Assessment

The Practical Classes for the IB Physics options (i.e. both the A & B courses) are organized around a set of eleven experiments, six in the Michaelmas term and five in the Lent term. Students taking the A, B or both A+B courses undertake different numbers and combinations of these experiments during the year.

Candidates taking a single Physics course will usually undertake a total of either 6 or 7 experiments during the year (3 in the Michaelmas term and either 3 or 4 in the Lent term) attending two 3¾ hour long afternoon sessions (over a fortnight) per experiment. One experiment must be written up as a Scientific Report.  (Students taking only Physics A undertake 7 experiments, whereas students taking only Physics B undertake 6 experiments since they also take an assessed computing course.)

Candidates taking both Physics courses are expected to undertake 6 experiments in the Michaelmas term and 4 experiments in the Lent term, but will complete each of these over the course of a week (usually in one day). They also undertake a longer experimental investigation in groups of four or five, spread over the practical sessions in weeks 6 and 7 of the Lent term. One of the experiments undertaken in the Michaelmas term must be written up as a Scientific Report.

The primary aim of the classes is to provide students with an opportunity to develop the key skills associated with the design and execution of experiments, and with analysing experimental data, hypothesis testing, presenting results and, importantly (especially for theoreticians), assessing others’ experimental results and analyses. Topics covered include a “systems approach” to experimental design, managing noise, offsets and systematic errors, and using experiments to tie down physical phenomena whose theoretical basis is uncertain or unknown – this is the standard situation for a research physicist.  For those taking both the A and B courses, presentational skills and team-working also feature in the extended investigation carried out and assessed at the end of the Lent term.

A secondary aim of the classes is to demonstrate aspects of, and reinforce the content of, some of the Michaelmas and Lent term lectures.

The synopses for both Physics A and B practicals outline the full set of 14 experiments available during the year, although students will only ever be expected to undertake a subset of these. Students must refer to the table at the end of the Lent Term synopsis to determine which experiments they will be required to undertake.

Synopsis

MICHAELMAS TERM: SYSTEMS AND MEASUREMENT

These experiments demonstrate key aspects of “real world” physics, i.e. as an experimentally-driven subject where measurements both validate theories and provide the stimulus for new theoretical developments. Many of the experiments also demonstrate critical features of the physics introduced in the Physics A Experimental Methods, Oscillations, Waves and Optics, and Electromagnetism lecture courses. Students will usually be expected to work in pairs, with the classes running from week 2 to week 7 of the term.

There are six experiments in total, each lasting about seven hours, as follows.

[1] Basic skills: Using a PicoScope; measuring input and output impedances, frequency response and phase shift; ensuring the measuring device does not affect the measurement; using an operational amplifier.

[2] Linear systems and feedback: An operational amplifier is used to explore various linear systems, including voltage amplifiers and integrators. The system concepts of negative and positive feedback are investigated.

[3] Twangs and clicks (data sampling and Fourier methods): An investigation of sampling, aliasing and Nyquist’s theorem, followed by the design, construction and use of apparatus to test the validity of a model developed to explain the properties of a tuning fork.

[4] Funky pendulum: A pendulum pivoting on a moving cart is used to achieve dynamical states that are only possible with closed-loop feedback. This experiment demonstrates automation through scripts, computer control, shows how to build an experimental rig in house using common components such as microcontroller boards and stepper motors. 

[5] Hysteresis: Building a simple magnetometer and investigating hysteresis in three magnetic materials.

[6] Faraday effect: Phase-sensitive detection is used to extract the very small optical rotation of light in glasses, induced by external magnetic fields.   As well as being an interesting physical phenomenon, this shows how to recover a very small signal in the presence a very high level of contaminating noise.

LENT TERM: WAVES AND OPTICS

These experiments demonstrate key aspects of wave effects in physics. The experiments also demonstrate critical features of the physics introduced in the Physics A Oscillations, Waves and Optics and the Physics B Electromagnetism lecture courses. Students will usually be expected to work in pairs, with the main experiments running from week 1 to week 5 of the term (with additional sessions in week 6 and 7 for single-subject students). There are seven experiments in total, each lasting about six hours, as follows.

[1] Key experimental techniques:  Students will work in prearranged groups to get familiar with the optical apparatus and methods used in many of the experiments later in the term. The practical exercises focus on measurements and aspects of the manipulation of light: refraction; reflection; speckle.

[2] Fraunhofer diffraction: A Helium-Neon laser and a range of different diffraction apertures are used to test the theory of Fraunhofer diffraction and to demonstrate spatial filtering in the Fourier domain. 

[3] Fresnel diffraction: A test the theory of Fresnel diffraction for circular apertures and obstacles, straight edges and slits. Obtain familiarity with Fresnel half-period zones and the Cornu spiral.

[4] Interferometry: To explore the interference fringes produced in a Michelson interferometer, to analyse the sodium D lines by Fourier transform spectroscopy, and to use a scanning Fabry-Perot etalon to analyse a laser’s output.

[5] Microwaves and waveguides: An investigation into guided waves and into the general properties of propagating electromagnetic radiation. The latter are more easily accessible in comparison with optical radiation because of the macroscopic wavelength of the microwaves.

[6] Ultrasound: To determine various properties of sound waves in air, including their speed and attenuation; to study simple interference and diffraction effects with sound waves; to measure the speed of sound in liquids using a ‘time of flight’ technique and determine its reflection coefficients at discontinuities.

[7] Wavetank: To study model water waves at the interface between two liquids. Aims are to investigate the dispersion relation of these waves, their frequency-dependent attenuation, and the propagation of wave packets.

 

LENT TERM EXTENDED INVESTIGATION (PHYSICS A+B STUDENTS ONLY), WEEKS 6-8

In weeks 6 and 7 students will, without the help of demonstrators, work in the same groups as in Week 1 on a diffraction-based experiment. In week 8, each group will give an oral presentation of their results in a mini-conference, attended by several other groups, Heads of Class, and demonstrators. Additional aims for this investigation are to develop time-management, presentational, and team-working skills.

 

LENT and MICHAELMAS TERM:  PHYSICS RESEARCH SKILLS

A career in research requires the ability to understand and target open questions in the field, to address these questions through a period of research (often as part of a team) and then to communicate the results to one’s peers, the wider physics community and often to a non-scientific audience. As a component of the IB Practicals, we therefore offer a Physics Research Skills IB course.

The Physics Research Skills IB course component incorporates taught and practical elements to allow students to develop essential skills in: reading and writing scientific literature; team-working; and in presenting scientific material.

 

MICHAELMAS TERM

In Michaelmas Term, there will be an introductory lecture to Physics Research Skills. The Nonlinear Methods Experiment (Experiment 3) will be 6 hours, the extra hour going to the Physics Research Skills Lecture. Subsequently, the Physics Research Skills component incorporates a Lecture on Scientific Writing Skills, which should benefit students when writing their Scientific Report.

LENT TERM

During Week 1, there will be a one-hour online Lecture on Poster Preparation and Presentations. In Week 7, there will be a one-hour online Lecture on Presentation Skills in particular, this lecture should benefit and inform students when preparing their Extended Investigation Presentation.

For students taking Physics A and B, the course will also include a Group Poster activity that will develop skills in team-working and in presenting scientific material. Each poster should present scientific material from one of their Lectures to their peers. The Poster preparation session will replace one of their practical sessions during Weeks 2-5. All posters will be presented in a joint poster session in Week 6. (B only students will not do the group poster).

Dr Chris BraithwaiteHead of Class All year
Richard KingTechnician All year
Helen MarshallTechnician All year
Mr Mark SmithTechnician All year
Dr Tijmen EuserHead of Class Lent
Prof Chris HaniffHead of Class Lent
Dr Paul RimmerHead of Class Lent
Dr Melissa UchidaHead of Class Lent
Dr Tijmen EuserOverall Head of Class Lent
Prof David BuscherHead of Class Michaelmas
Prof Pietro CicutaHead of Class Michaelmas
Prof Chris FordHead of Class Michaelmas
Dr Andy IrvineHead of Class Michaelmas
Prof Pietro CicutaOverall Head of Class Michaelmas
Dr Adrian IonescuHead of Class Michaelmas/Lent
Course section: