CTS Guide: Electric Charge and Current, pp 172-173- Section IV Research Summaries

Complete Circuit

  • Studies by Shipstone (1985), Arnold and Millar (1987), and Borges and Gilbert (1999) show that, before instruction, many K–8 students are not aware of the bipolarity of batteries and lightbulbs. They do not recognize the need for a complete circuit and have difficulty making a bulb light when provided with a battery and wires. Furthermore, even high school and university students have shown difficulty with this task.

  • When asked to assemble a circuit with a battery, bulb, and wires, some students use a source-consumer model in which the battery gives something to the bulb. In this context, younger students will often draw a single wire going from the top of the battery (unipolar model) to the bulb. Another similar model held by younger and older students involves two wires, each one going out of an end of the battery (bipolar model) and touching the bulb with the electricity going from the battery to the bulb in each wire. Some students will regard one wire as the “active” wire and the second wire as a “safety wire” (Driver et al. 1994).

Electrical Charge

  • Using dots or circles in their drawings can be an indication that students are using the particulate model to also account for electric interactions (Casperson and Linn 2006).

  • Younger students sometimes confuse repulsion and attraction between static charges as magnetism (Naab and Henry 2009).

  • Some students may incorrectly believe that “negative” means “not charged” and positive means “charged.” Students may also incorrectly believe that neutral is another type of charge. Neutral means there is an equal number of both positive and negative charges (Harrington 1999).

  • Many students will associate electric charge with conductors (such as metal). This confusion arises from the difficulty distinguishing between the presence of charge and the movement of charge (called electric current) (Harrington 1999).

  • Studies have reported a variety of ideas students have about charge transfer. Some students believe there is no transfer between a charged object and a neutral object and that charge transfer between objects occurs until an object is neutral (Guruswarmy, Somars, and Hussey 1997).

  • In the study of electricity, students often confuse charge and current (Andersson 1986).