Simple Circuits Curriculum

image of bathroom lights

This lesson engages students in experimenting with series and parallel circuits and asks them to model what they think is going on and why. It asks students to record and compare their results and to begin thinking about why the differences exist between the different types of circuits.

Section 5: Understanding Goals

Subject Matter

  • When you arrange two bulbs in series, they will shine less brightly than if there was one bulb, and less brightly than if they are arranged in parallel. Both bulbs have equal brightness.
  • Two bulbs arranged in parallel shine as brightly as when there is only one bulb. (However, if you keep adding bulbs in parallel until there are many bulbs, eventually they will all get dimmer.)
  • Arranging batteries in series increases the amount of voltage in the circuit.
  • Arranging batteries in parallel results in the same amount of voltage in the circuit but there is more (battery) chemical available, so the batteries are able to last longer and will be able to maintain their voltage (differential) when higher current flows in the circuit. The bulbs will be the same brightness as they were before the additional batteries were added.

Causality

  • Students could analyze series and parallel circuits using any of the causal models previously discussed, and find ways to explain the results. However, their explanations would differ from scientifically accepted explanations.
  • The Cyclic Simultaneous Model is a good intermediate model for explaining what happens in series and parallel circuits. It pushes us to view the circuit as a system instead of as isolated parts.