Unit 2: Electricity, Electrons, and Energy Levels

This Nuffield Advanced Physics Unit explored the topic of electricity and matter. It sought to develop basic ideas about current, potential difference, and charge, and to show some of the electrical properties of materials. These ideas were then used to understand evidence for the existence of electrons within atoms and also evidence that atoms exchange energy in lumps, having discrete energy levels.

Contents of the Students’ book
*To the student
*Summary of Unit
*Questions
Part One: Things which conduct
Part Two: Currents in circuits
Part Three: Electric charge
Part Four: Stored energy
Part Five: Electrons and energy levels
*Answers
*The experimental evidence for the existence of energy levels in atoms
*Electrochemical machining
*Books for Unit 2
*Terms, units, laws, formulae, and data
*Symbols for circuit diagrams

Experiments suggested for the Unit
2.2 Conduction by wires
2.3 Effects of temperature on resistance
2.4 Attempt to measure conduction in polythene
2.5 Conduction by coloured salts
2.6 Four-terminal boxes
2.1 Measurement of potential difference
2.8 Comparison of two dry cells
2.9 The electrometer as a voltmeter
2.10 Measuring voltages without voltmeters (crude attempts)
2.11 Measuring a voltage without a voltmeter
2.12 Drop in p.d. of a supply delivering current
2.13 Comparison of two supplies
2.14 Capacitors and charge
2.15 Charging a capacitor at a constant rate
2.16 Spooning charge (using electrometer)
2.17 Decay of charge
2.18 Energy stored in a charged capacitor
2.19 Energy proportional to V squared
2.20 Heating by capacitor discharge, energy proportional to V squared
2.21 Catapulting an air track vehicle
2.22 Energy stored in a spring
2.23 Electron streams
2.24 The Millikan experiment (charge on an electron)
2.25 lonization of air
2.26 lonization by electron collision
2.27 Collisions on an air track
2.28 Detection of ions
2.29 Excitation of xenon
2.30 Collision of light and massive objects