PASCO Specialty & Mfg. ES-9042A User's Manual
Contents
1. FAX 916 786 8905 www pasco com Faraday Ice Pail 012 04393C Ground the ice pail i e connect the inner pail to the shield by touching the inner pail and the outer shield at the same time with the finger of one hand See Figure 2 While conducting the experiment it may be convenient to continually rest one hand on the upper edge of the shield This also grounds the experi menter providing the electrometer is connected to both ground and shield and it allows the ice pail to be easily grounded whenever necessary Closed Open Figure 2 gt NOTE When removing your finger from the inner pail after grounding it make certain that you are still touching the outer shield DO NOT re move your hand from the shield before releasing the inner pail as this sequence will not effectively ground the inner pail Make sure the electrometer reads zero indicating that there is no charge on the ice pail Procedure A Rub two charge producers together to create a charge on them Insert one of the wands into the ice pail but do not let it touch the pail Note the electrometer reading Remove the object from the pail and again note the electrometer reading Insert the wand again allow it to touch the ice pail and then remove it Note the electrometer reading Momentarily ground the ice pail and then touch the object to the pail again Note the electrometer read ing Does any2. charge remain on the object What is the conclusion about the induced charge on the ice pail as compared to the charge on the charge pro ducer gt NOTE The charged object must be inserted at least into the lower half of the ice pail Try inserting it for ex ample approximately one centimeter below the top of the pail and attempt to explain your results There may be a small charge retained on the exposed plastic between the aluminum disk and the aluminum rod on the charge producers This residual charge does not transfer readily when the disk is touched to the pail Therefore before starting the experiment breathe on the exposed plastic of the charge producer so that the moisture in your breath will tend to re move any residual charge Procedure B Starting with initially uncharged charge producers rub the blue and white materials together Using the Faraday Ice Pail measure the magnitude and polarity of their charges By using the results from Procedure A it is not necessary to touch the charge producer to the pail What relationship exists between these charges produced by contact Ground the charge producers and rub them together inside the ice pail What is the reading on the elec trometer Remove one charge producer and note the electrometer reading Replace this charge producer but remove the other and note the electrometer read ing Ground the charge producers again Rub the white mater
3. Instruction Sheet for the PASCO 012 04393C Model ES 9042A Faraday Ice Pail Complete instructions for the operation of PASCO Elec Introduction trostatic equipment can be found in the ES 9051 Acces The Ice Pail designed by Faraday is an excellent product for sampling a charge distribution It operates on the principle that a charge placed inside a conducting sur face will induce an equal charge on the outside of that surface For example if a charged ball were hung inside a coffee can the charge on the outside of the can would equal the charge of the ball The charge can be measured with an electrometer such as the PASCO Model ES 9078 Basic Electrometer The PASCO Model ES 9042A Faraday Ice Pail is a wire mesh cylinder measuring 10 cm in diam eter by 15 cm deep with a wire mesh bottom It is mounted on three insulating rods along the outer edge of a wire mesh shield The wire mesh shield not only ensures complete vis ibility of the experiment but also helps eliminate the problem of stray charges and AC fields To prevent stray charges from producing erroneous re sults it is extremely important that the person performing the experiment be continually grounded while perform ing the experiment The Ice Pail needs to be temporarily grounded prior to starting the experiment A charged object such as the PASCO Model ES 9057A Charge Producers and Proof Plane is placed in the grounded ice pail without touching it an
4. d the elec trometer indicates the potential between the ice pail and ground The greater the charge the greater the potential Thus we can easily measure relative charges by varying the charges in the ice pail and observing the potential indicated by the electrometer sory and Demonstration Manual included with the Demonstration System and the ES 9055 Laboratory Manual included with the Electrostatic Laboratory Sys tem Charge Producer Red Clip Electrometer Figure 1 Demonstration Faraday Ice Pail and Charge Production Since the Faraday Ice Pail is used so frequently in elec trostatic demonstrations one should examine the rela tionship between the charge induced on the ice pail by an inserted object and the actual charge on that object Using the ice pail one can then investigate the nature of charging an object by contact as opposed to charging by in duction Equipment needed Faraday Ice Pail charge producing ob jects such as ES 9057A Charge Producers electrometer Setup Connect the electrometer input lead red alligator clip to the ice pail to create a system for measuring charge The electrometer ground lead black alligator clip attaches to the shield Setup is shown in Figure 1 Adjust the sensitivity of the electrometer so that most readings appear in the upper 2 3 of the scale FASC OR scientific 10101 Foothills Blvd Roseville CA 95747 7100 Phone 916 786 3800
5. ial against the aluminum proof plane Measure the magnitude and polarity of the charges Now rub the blue material against the aluminum surface and record your measurements Construct a list of materials such that if a material lower on the list is rubbed against a material higher on the list the charge on the higher listed material is always positive Such a list is called an electrostatic se ries To Reach PASCO For Technical Support call us at 1 800 772 8700 toll free within the U S or 916 786 3800 email techsupp PASCO com Tech support fax 916 786 3292 PASC Oi
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