4. Phases of Matter

About this Lecture

Lecture

In this mini-lecture, we consider the phases of matter, focusing in particular on: (i) the phases: solid, liquid, and gas; (ii) a demonstration of such phases using liquid nitrogen and water; (iii) the properties of solid, liquid, and gas, and what distinguishes them; (iv) phase diagrams (the pressure vs. temperature of a substance) and determine where each phase is represented on the plot; (v) transitions between phases (melting and freezing, vaporisation and condensation, sublimation and deposition); (vii) a demonstration of dry ice (frozen carbon dioxide) in a rubber glove, where we see that sublimation from solid to gaseous form inflates the glove; (viii) the triple point and the critical point on the phase diagram; (ix) how pressure affects the boiling point of a substance; and (x) an exercise for students to try on their own.

Course

In this course, Dr Janet Lovett (University of St Andrews) explores properties of matter. Throughout this course, we present 14 demonstrations. In the first mini-lecture, we discuss atomic structure and look specifically at what makes up the elements (protons, neutrons, and electrons), models of the atom, energy levels, and element emission spectra. In the second mini-lecture we explore the discovery of the electron, focusing on a series of demonstrations that illustrate J.J. Thomson’s cathode ray experiment and how electron charge was first determined. The third mini-lecture turns towards nuclear physics, where we discuss nuclide stability, mass and energy, binding energy per nucleon to understand nuclear fusion and fission, and radioactivity. In the fourth mini-lecture, we take a step back from atoms to consider matter as a whole, specifically discussing the phases of matter, and how pressure and temperature affect these phases. In the fifth mini-lecture, we explore the relationships between pressure, volume, temperature, and number of particles before introducing the ideal gas law. In the sixth mini-lecture, we look at the forces between particles and how they interact in a substance.

Lecturer

Janet Lovett is a Lecturer in the School of Physics and Astronomy at the University of St Andrews. Her primary research interest is in measuring nanometre distances for structural biology using Electron Paramagnetic Resonance (EPR) spectroscopy. Dr Lovett teaches a first-year ‘Properties of Matter’ course at the University in addition to other courses such as magnetic resonance.