All Charged Up

Physical Science began its walk through electromagnetism today with the introduction of the concept of charge and the methods of generating charges on neutral objects. The ability of charge to produce electric forces was introduced and the use of Coulomb's Law to calculate the magnitude of electric force between two charged objects was discussed. You will get practice working with Coulomb's Law problems in class, so don't be worried if we seemed to move through the formula and concept rather quickly. Tomorrow in class, you will conduct a lab investigation that will focus on charge generation, the effect of electric forces on matter and the function of an electroscope.

A block Physics conducted a lab investigation on plane and curved mirrors. The basic properties of each mirror was examined and the law of reflection was quantitatively documented for a plane mirror. Tomorrow's lecture will continue through the properties of light and begin to look more closely at reflection and mirror types. E block lost its lab today due to an assembly. If there is time, we'll try and make up the lab at a later date, but time is growing short...

Honors Physics discussed the finer points of spherical mirrors and reviewed the use of the mirror and magnification formulas for evaluating mirrors. We didn't delve too deeply into ray diagrams, as we will spend more time with them when we discuss lenses, but you should be able to draw a basic ray diagram for a converging mirror forming a real image. Parabolic mirrors are not emphasized in this chapter, as their use in optics is rather limited, but where they come into their glory is with radiotelescopes (an EM wave is an EM wave) and for concentrating sunlight into a valuable and powerful source of energy. Here are a couple a videos on the use of parabolic mirrors for heating water. May seem minor, but consider that solar panels are extensively used to power household hot water heaters, and boiling water (steam) is the juice behind steam engines...