The electrometer differs from the electroscope in existence of a scale with divisions. In amateur version of this device it is absolutely optional to graduate a scale in SI units or any other standard. Even if to use relative units, it will be enough, for example, to compare charges of several electrified objects.
Instruction
1. Manufacture the round dial for the electrometer. Its zero division has to be located from above. The last division arrange on the right. Between them place some more divisions. Assign them numbers.
2. As an arrow use a thin strip of a foil. At the distance from the beginning of a strip making slightly more than a half of its length (for creation of the small imbalance holding an arrow vertically), paste to it an easy piece of the tubule twisted from the same foil.
3. Paste the dial to a wooden board. In its center, using a pin with a ball on the end, attach an arrow through a tubule.
4. To the left of an arrow, parallel to it and strictly vertically, fix on the dial not movably one more strip of a foil. Connect it to a pin (but not to the arrow that it could rotate freely). Tension on an arrow will move through a conducting tubule.
5. From above, over the dial, fix on an electrometer board the metal hollow object, cylindrical or spherical shape having diameter about 50 mm, and in a case with a cylinder - as well height close to this value.
6. Connect a hollow object to a point of connection of a pin and a motionless strip. The wire which carries out this connection has to be laid so that not to prevent an arrow to rotate.
7. Make a support for the device. Use the self-made electrometer just as the ordinary electroscope, with only that difference that it has though conditional, but nevertheless graduation.
8. Use the electrometer mainly in such experiments where quantitative measurements are required and therefore opportunities of the ordinary electroscope are not enough. To prompt to you what have to be these experiments, the teacher of physics can. Remember that the device has smaller sensitivity, than devices similar to destination on the basis of special electrometric lamps.