Question

You are provided with some commonly occurring materials like glass, wool, fur, Styrofoam, aluminum foil etc, in various shapes and sizes. You are also given the ‘Tribo-electric’ series that includes these materials, and an electroscope. This lab requires you to come up with five simple experiments using a variety of these materials, where you charge up two objects by conduction, and then test whether they are charged or not using conduction, induction or polarization. Make sure you include one case of electroscope use for testing charge on an object, and at least one of repulsion between two objects carrying like charges. The experiments that you come up with can be made effective using the tribo-electric series, since it gives an indication of which two materials will charge up well on contact with each other, and which one will be positive or negative. Your lab report should include the following: Objective: A short and to the point sentence providing the objective of the lab. This will be followed by a list of your experiments as: Experiment #: A short sentence or two describing your experiment. Observation: What you actually observed. Explanation: Explain briefly what you observe. Include one full explanation of each process: conduction, induction, polarization, and also one of the working of the electroscope. Refer to the tribo-electric series where required. If you have explained a process once, you do not have to repeat it for other experiments; just mention the name of the process. An experiment that is theoretically sound may sometimes not work well when performed. If that is the case, include in your lab report the factors that you think contributed to the failure of that particular experiment.

1)Induction experiment : rub balloon on shirt (becomes negatively charged, then bring close to an aluminium foil ball ) show diagram on the charges

2)Polarization experiment : rub balloon with hair , neutral paper will be attracted to balloon.

On top is the instructions provided i came up with 2 experiments one induction and the other polarization please show a diagram for the charges (what happens) and explain what should be observed and theoretical explanations of induction and polirization in these specific experimets I came up with! :)

Answer 1

As you need answers for only specific experiments, providing the same here;

Before going for the experiment lets look at the Triboelectric series for the materials mentioned,(ranking from highly positive to highly negative)

# Glass

# wool

# fur

# aluminum foil

# Styrofoam

Induction experiment:

Since the balloon is neutrally charged, after rubbing the balloon on a shirt, the balloon becomes negatively charged. Now when the balloon is brought near to an aluminum foil(which is positively charged ) then the balloon is attracted towards the foil.

Polarization experiment:

Since the balloon is neutrally charged, when it is rubbed on hair(which is positively charged, balloon gains some positive charges. Now the balloon is positively charged. Paper is neutrally charged. Thus, paper bits are attracted to the balloon and charges redistributed in both balloon and paper.

The picture is as shown;

the main difference between induction and polarization is;

Induction means the charges are induced on material from another material. For example, the shirt induced negative charges to the neutrally charged balloon. Again the balloon induced negative charges to the foil.

Polarization is a redistribution of charges on the material. That is when the balloon was positively charged the charges got redistributed and became neutral. Polarization doesn't induce any charge.