If we look up the meaning of the word ‘Instrument,’ we see that it includes the definition – ‘a tool or implement, especially one used for delicate work or for scientific or artistic purposes; any of the various devices for indicating or measuring conditions…’.
Many of the experiments we do use instruments, from the humble scale to the far more sophisticated ones. Where do these come from? As we have seen earlier, Boyle and his co-workers built their own instruments to measure pressure and volume. Any new scientific idea meant that the scientists usually built the means of making the measurements needed. However, as students we use instruments already made calibrated and sealed, and so the link between the principle and the measured is obscured. An important part of the instrument – calibration, has no meaning for the students because the values seem to come from nowhere. So we cannot even imagine that values can differ according to how the instrument is held or used. Digital and microprocessor technology has further blurred the connections. [Many of us used to use the common incandescent lamp as a tool to measure line voltage. The brightness/dimness of the lamp, whether the filament could be seen, all gave a good idea of the voltage. The CFLs/Tubes/LEDs give the off/on modes only].
We can build simple working versions of various instruments. There are many advantages to doing that:
1. We can play with it however we please.
2. We know how it works.
3. We know when it isn’t working.
4. We can fix it if it breaks.
5. We know what it can do and what it cannot.
The author works with Centre for Learning, Bangalore. She can be reached at [email protected].