Extension Modules for GCSE Physics

The Salters GCSE physics course (1993 – 2007) was based on the physics content from the double award science course, with the addition of three new modules to provide coverage of the extra content.

When the chips are down: The module is introduced by considering the main features of a TV set.

The operation of the time base and gain controls is demonstrated and these are related to the control of the electron beam in the tube of a TV. Students use diodes to rectify an ac signal with both half and full wave rectification. They compare LEDs with light bulbs. The function of Zener diodes is also considered as protective devices.

Students use the idea of ‘holes’ and n- and p- type semiconductors to explain the operation of thermistors, light dependent resistors (LDRs) and the diode. The use of capacitors to ‘smooth’ the output from a rectifier is demonstrated. Students carry out experiments with capacitors. Students experiment with RC circuits and the use of the time constant to link capacity, resistance and rate of discharge. They see how time delays can be varied and consider applications of this.

All systems go: This physics extension module from the Salters science course deals with binary digital electronic devices, taking a systems approach. Ideas of input, output and control are considered and the concept of feedback. The use of logic gates to control switches and latches is studied and relays are explored as a way of switching larger currents.

We have the technology: This physics extension module from the Salters’ science course covers the action of sensors and amplifiers in electronic systems. Potential dividers are studied as a way of supplying different voltages. The action of light dependent resistors and thermistors in potential dividers is studied. Transistors are introduced as devices to give sharp switching in response to changing conditions. Transistors are then considered as amplifiers and some amplifier circuits are investigated. Ideas of memory and feedback are briefly introduced