Simple Circuits Curriculum

Section 1: Background Information

Finding Configurations That Light the Bulb

In this lesson, students experiment with lighting a bulb using a single wire and a battery. Many students think that it is impossible to do this with just one wire and are surprised to discover that it is not only possible, but that there is more than one configuration that works. For this initial exploration, students should work individually so that each student has a chance to explore his or her current conceptions. They are encouraged to try to find as many different configurations as they can. Students are purposely not given battery or bulb holders because they tend to think that the bulb holder is necessary for the bulb to light.

Implicit Causal Models Impact Which Configurations Students Try

Students typically have implicit causal models for what is going on, but the focus of this lesson is on finding configurations that work. The link to underlying causal models will be the explicit focus of the next lesson. After the exploration, students are asked to reflect on what causal models they hold.

Students typically begin trying to light the bulb by attaching the wire to the battery such that one wire connects the battery directly to the bulb so electrons can flow in one direction from the battery to the bulb. They may be surprised when this doesn't work because it fits with their notion of what it means to "plug something in." (For this reason, an activity later in the unit involves separating some extension cords.) Some students believe that they need two wires to light the bulb. These students are often surprised to find that they don't.