If you are in AP physics, please complete this lab in your lab notebook! If you are not in AP Physics, please complete it on a separate piece of paper and place it in the manila folder.

This is a virtual lab based on a simulation developed by the Phet Interactive Simulations Group at the University of Colorado. The lab is embedded on this page and can also be accessed here.

Use the vocabulary below to describe what happens. You may or may not need to use all of the words.

Please answer questions without anthropomorphizing protons and electrons. That means giving them them human characteristics and emotions, such as saying "Protons and electrons want to be together."

Vocabulary

• Charge: An object is positively charged when it has more protons than electrons and an object is negative charged when it has more electrons than protons.
• Polarization: When an has a more positive charge on one side and more negative charge on another side.
• Charging by Friction: When two objects are rubbed together and electrons transfer from one object to another.
• Charging by Induction: When an object causes another object to be charged without exchanging electrons. Often results in a polarized charge.
• Electrostatic Discharge: Electrons move through the air from an insulator to a grounded conductor due to repulsion. Causes a spark to appear, and eliminates charge in an object.
• Grounded: A conductor is grounded if electrons are able to move from that conductor to the ground, effectively providing a way to eliminate charge.
• Attraction: Whenever two objects experience a force pulling them together.
• Repulsion: Whenever two objects experience a force driving them apart.
• Electronegativity: The extent to which a particular chemical or substance attracts electrons. Electrons will tend to move from more electronegative substances to less electronegative substances.

1. Rub the balloon against the sweater. What happens to the electrons? Draw a diagram illustrating what happens that includes moving electrons. Describe what happens using the vocabulary above.
2. After rubbing the balloon against the sweater:
   • What is the charge of the balloon and why?
   • What is the charge of the sweater and why?
   • What happens to the balloon and the sweater?
3. What happens when the charged balloon is moved near the wall? Draw a diagram illustrating what happens including the moving charges, and describe it using the vocabulary above.
4. Why is the balloon attracted to the wall?
5. Set the simulation to have two balloons. Can you get them to repel each other? How?