Physics 133 Week 1 (Electrostatics and Coulomb Force)
Electrostatic Charge
Triboelectric Series
When two objects come into contact with each other the objet with the larger electron affinity will tend to "take" electrons from the other object, leaving you with two statically but separately charged objects.
Electrophorus
This device can be used to show your students that by grounding a conductor while in contact with a charged insulator you can create two objects with opposite static charge.
Electroscopes
Here are a few of the electroscopes you can find in the demo room! Remember that static positive charge will dissipate rapidly on a good day, and is nearly impossible to maintain on a humid day.
The Coulomb Force
Coulomb Pivots
By allowing a rod (charged or neutral) to rest on a stand with a pivot, you can use a second charged rod to introduce your students to my favorite force ;-) The Coulomb Force
Pith Balls
These small, light, conductive spheres can be used as another way to demonstrate the Coulomb force. Whether with one ball or two, you may need to rub your charged object across the pith balls several times in order to transfer charge onto the balls.
Electrostatic Pom-Pom
Once these are charged, the tassels on the pom-poms will spread apart in attempt to maximize their distance away from each other. These can even be used as a make shift charge sensor as long as you know the charge on one of your object.
Transferring Charge
A charged rod can be used to pick up saw dust off of a table. As charge slowly transfers to the saw dust, you will see it shoot of the rod.
Acceleration from Induction
When a charged object is brought near a conductor which can easily roll, the induced charge separation and responding Coulomb force will cause the object to accelerate.
Bending Water
By bringing a charged object near a small stream of water, the natural dipole in water will cause the stream to bend towards the charged object.
Electrostatic 2x4
Set the 2x4 on the accompanying stand, and make sure it can rotate easily. Once you are ready, bring the handheld VdG (or any strongly charged object) nearby to cause the massive piece of wood to rotate due to the Coulomb Force.
Coulomb and Distance
By using two parallel plates, with one hooked up to an electroscope and one hooked up to a static charge generator, you can vary the distance between the plates to show your students how the Coulomb force depends on distance.
Van de Graaff Generator
These electrostatic charge generators are a great way to excite your students and investigate multiple examples of static charge and the Coulomb force. Make sure that you have a grounding rod connected to the VdG to avoid a shock.