Electric charge lab
| Charging by friction | Charging by induction |
| There is contact between a charged body and a neutral body. The rod and the fur were rubbed together for the rod to obtain its positive charge from the fur. | The charged body is brought closer to the neutral body, but the two are never contacted. For instance, the charged rod was placed near the metal sphere without touching it. |
| The charge on each object changes, but the total retains. The variations in charges between the rod and the fur are significant when compared to the mean total value of the charges of the objects. | Both the charge for each body and the total retains. The variations in the charges of the sphere and the rod insulation are minimal compared to the mean total value of the two objects. |
| There is charge loss due to the disappearing of the additional induced charges that were obtained during the rubbing of rod and fur. | No or very minimal charge loss. The metal sphere and the rod retained its charge as long as it was in close contact with the rod during the experiment. |
| Upon removal of contact, the charged objects retain their charges. The rod retained its charge even after being separated from the fur. | When a charged object is removed, the other object loses its charge. The metal sphere lost its charge immediately the charged rod was removed. |
- i) Metal sphere. It has a mean positive charge compared to the rod that has a negative charge. In turn, the rod has a positive charge value against the fur’s negative when charged by the fur. Therefore, the metal sphere has the highest ranking.
- ii) Rod. It has a positive mean charge in comparison to the negative mean charge of the fur, and also it has a negative mean charge value when it charges the metal sphere. Therefore, it is an intermediary in the ranking.
iii) Fur. It has a negative charge value compared to the rod’s positive charge when it charges it while the rod has a negative charge against the metal sphere. This means that the fur is the lowest in the ranking.
- i) Leather. It has a positive charge when rubbed against all of the materials below. For instance, this is the reason for its enormous accumulation of dust particles compared to other materials.
- ii) Glass. It is negative in comparison to the leather but positive against all the materials below. For instance, our tv screens at home accumulate dust particles now and then.
iii) Paper. When rubbed against all these materials, it becomes positive compared with cotton and wood but negative when compared with leather and glass.
- iv) Cotton. Its charged value is only positive against wood but negative for the leather, glass, and counter-wise positive cotton materials.
- v) Wood. Its charged value becomes negative when rubbed with all of the above materials.
- The different materials used, including rod, metal sphere, and fur, were used varyingly to obtain different charge values.
- The charging distance between the objects for the case of induction charging remained the same for different runs. Charging time for each of the experiments was fixed. The analysis methods used for the two trials, triboelectricity and induced, was fixed for each of them. The techniques for obtaining data were fixed for the different objects. The same charge sensor was used to measure the charge intensity for all experiments.
- The charge intensity values depended on the rod, metal sphere, and fur materials and also the methods used for each of the objects.