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Understanding Goals
Subject Matter
- Electrons are conserved in a circuit.
- The bulb lights when electrons flow in the circuit. Flow requires a continuous "push."
- The battery does "work" by providing push or tension.
- Voltage can be thought of simply as push, or the force that moves electrons.
- The circuit is process-like, not substance-like. There is no point at which the circuit is "empty." Everything is made up of atoms; therefore, there are electrons all along the wire at all times.
Causality
- At the particle level, the causality in a Cyclic Simultaneous Model explains the process of flow better than Simple Linear or Cyclic Sequential Models. It involves thinking about the entire circuit as a system.
- In the Cyclic Simultaneous Model, electrons repel and are repelled by those around them. In essence, cause is effect and effect is cause. This results in flow.
- The battery completes the Cyclic Simultaneous Model by pushing the electrons back to the negative contact.
- It can be difficult to move beyond linear models of electrical flow. Many everyday experiences encourage us to view it as a linear process (such as one-way electrical cords coming out of appliances).
©2004, President and Fellows of Harvard College, Understandings of Consequence Project
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