Exploring Static Electricity

Activity Overview:In this activity, students explore charging by induction through a hands-on demonstration followed by a simulation of the same demonstration using the POE inquiry model. The value of the simulation is that it explains the observed phenomena by showing changes in charge distributions.

NOS tenets addressed:
1. Scientific knowledge is developed from both observations and inferences.
2. Scientists use many methods to develop knowledge.

Simulation URL:

Standards/Benchmarks

PS.1The student will demonstrate an understanding of scientific reasoning, logic, and the nature of science by planning and conducting investigations in which

j) valid conclusions are made after analyzing data;

k) research methods are used to investigate practical problems and questions;

l) models and simulations are constructed and used to illustrate and explain phenomena; and

m) current applications of physical science concepts are used.

PS.11 The student will investigate and understand basic principles of electricity and magnetism. Key concepts include

a)static electricity

Materials: balloon, wool sweater, wall

Procedure

  • Review (2 min):
    Review the terms observations (using your 5 senses to gather information about your surroundings) and inference (a conclusion based on evidence) with students.
  • Predict (5 min):
    Ask students what they think will happen when you rub a balloon with wool and hold it near the wall. (This is the research question in this investigation.) Ask studentswhy they think this will happen.
    Possible Answers: The balloon will stick to the wall (they’ve seen it before), the balloon will fall to the ground (gravity), the balloon will float (balloon is filled with Helium).
  • Observe (10 min):
    Rub a balloon against wool sweater and hold it close to the wall.
    Have students make observations of what happened (these are their data) and inferences as to why it happened. (It should “cling” to the wall.)
    Ask students if their predictions were correct.
    Open the simulation and repeat this within the simulation with the charges off so they can see the simulation works the same way.
  • Explain (10 min):
    Turn on the charges and reset the simulation.
    Repeat the activity guiding students to look carefully at the behavior of the charges as the balloon is rubbed on the sweater and then as it is moved toward the wall.
    Ask students what they observe about the charges?
    Ask students what they infer about the behavior of the balloon based on the charges?
    Name the phenomenon by which the balloon “sticks” to the wall as charging by induction.When an object gets charged by induction (the wall), a charge is created by the influence of a charged object (the balloon) but not by contact with a charged object.The word induction means to influence without contact. Clarify for students that rubbing the balloon with the wool sweater is not charging by induction – it is charging by friction – because the sweater is in direct contact with the balloon to create the charge differential and negative charges are directly transferred in this process from the sweater to the balloon.
  • NOS Debrief: Following the “explain” portion of the lesson, ask students how they were behaving like scientists. Be sure to reinforce that they were using both observations and inferences in developing their understanding of charging by induction (static electricity). Also, this investigation is non-experimental in nature, therefore the idea that scientists use many approaches to doing science including (observational studies), should be hi-lighted.

Modifications: Use only the simulation, omit the physical demonstration.

Extension:Ask students to describe the different approaches to charging on the simulation (e.g., the balloon is charged by friction – an actual transfer of charges from the wool sweater to the balloon) vs the balloon charging the wall (by induction).

Assessment Strategies: An exit slip asking to students to explain what happens to the charges on two different objects (e.g., a wall and the balloon) when one has a positive charge and the other is neutral.