Electromagnetism

Now that Physical Science has undertaken a study of magnetism, it can be said that the entire physics curriculum is currently devoted to that broad and profoundly important field of electromagnetism. Yesterday, Physical Science explored the shape and strength pattern of the magnetic field surrounding a bar magnet. It was clear that field strength increased near the magnet's poles and weakened at a distance from these poles, even when measured along the body of the magnet. The north and south poles had equal, but opposite, field strengths. Today's discussion centered around hard and soft magnets, the nature of magnetic fields and forces and how to draw and interpret magnetic field lines. Tomorrow, we will continue our discussion about the Earth's magnetic field and the function of compasses. Note: as we discussed in class today, magnet strength can vary greatly, as illustrated below:



Physics continued their discussion of voltage, resistance and current and bundled these concepts into Ohm's Law. A Block will conduct a lab investigation of Ohm's Law tomorrow, but most everyone in E Block will be dismissed for prom preparations. We will not make up this lab for E Block, so the basic results were discussed in class today.

Honors Physics conducted the Ohm's Lab today and the results were very good. For resistors, a graph of voltage vs. current produced tight straight lines for which the slope was the value of the tested resistor. For the light bulb, a non-ohmic device, the graph demonstrated a non-linear relationship. For low voltages, resistance did not increase as quickly as for higher voltages. Explains why light bulbs typically burn out right when you turn them on - low resistance with increasing voltage means proportionally greater current draw. This increased current can over-tax a older filament, leading to breakage. Tomorrow, C Block will further its discussion of capacitors and enter into the arena of circuits. Activities in G Block will depend upon attendance due to prom dismissals.