Describes a simple circuit based on an inexpensive quad operational amplifier that permits a direct-reading temperature instrument to be constructed using silicon diodes. Encourages the use of this equipment in introductory thermal experiments. (DDR)

Year 11 students investigated the real-world problem of whether screws are really brass. It allowed them to use the colorimeter and computer interface in a way that was easily understood and models normal practice in testing laboratories. Screws were dissolved in nitric acid and their absorbance of red light was compared with a standard curve.…