Go with the Flow
An example of electrical conductors.Copyright Wikimedia Commons http://commons.wikimedia.org/wiki/File:ACSR_%26_ACCC_Conductors.JPG
Students make sense of the phenomenon of electricity as they gain an understanding of the difference between electrical conductors and insulators. Using the science and engineering practices of generating and comparing solutions and making observations, students gain experience recognizing a conductor by its material properties. Students explore the disciplinary core ideas of energy and material properties and the crosscutting concepts of energy transfer and standard units in preparation for the associated hands-on activities. In one activity, students build a conductivity tester to determine whether different objects are conductors or insulators. In another activity, students use their understanding of electrical properties to choose appropriate materials to design and build their own basic circuit switch.
We know that electrical engineers design the circuits and batteries that run the appliances we use every day. But another aspect of designing electrical devices is deciding which materials make the best conductors and insulators for a given situation. Engineers consider a material's level of conductivity, ability to dissipate heat, ductility and resistance to corrosion at certain temperatures. Only through the smart selection of materials for parts, wiring, external housing and microchips are engineers able to design devices and appliances that operate correctly, dependably and safely.
After this lesson, students should be able to:
- Predict whether an object is likely to conduct electricity.
- Distinguish between electrical conductors and insulators.
- Understand that the electrical properties of a material determine how it can be used in an electrical circuit
- Understand why engineers must consider the materials for parts, wiring, external housing and microchips in order to design electronic devices and appliances.