A Sparkling New Week

Honors Physics investigated the function and limitations of heat engines. Heat engines allow us to convert heat into usable work, but at a substantial cost of efficiency. We looked at how to calculate that efficiency and emphasized that the value was a theoretical maximum. Actual heat engine efficiencies are always lower. Tomorrow, we’ll tackle the idea of entropy and how it applies to all systems and the universe as a whole. Wednesday, exam review. Thursday, exam.

Physical Science B reviewed basics of wave interactions and then took that information to examine the phenomenon of standing waves. We made these wave formations in lab, but today put some flesh on the bone for the topic as a whole. You should be able to identify the parts of a standing wave, calculate the wavelength, describe how standing waves are formed and recognize that only certain wavelengths are permissible for a standing wave. The practice test I gave you in class will be the first thing we discuss tomorrow before launching in to a general review of the chapter. Wednesday – MCAS wave review. Thursday – exam.
Physical Science E followed the same agenda as for B Block, but will have their lab experience with standing waves tomorrow. You will also get your MCAS review packets and will have time to work on them when the lab is concluded. Wednesday is general review day and Thursday is the day of the exam.

Physics F investigated how calorimeters can be used to determine heat content of materials and compared the heat content of two fuel sources – paraffin and Sterno. By using the mass of the water in the calorimeter, the water’s final and initial temperatures and the specific heat of liquid water, the amount of heat energy delivered by the fuel source could be calculated (Q = mcΔt). We then compared this heat release to the amount of material burned to release the heat to determine the heat content per unit mass. The second part of the lab centered on the solid-liquid phase change and allowed students to determine the heat of fusion for water. How many joules of energy were required to change the temperature of a fixed mass of water. Measure that energy against the mass of ice melted (received the heat lost by the liquid water), to get the latent heat value for the ice (J/g). Tomorrow, we’ll finish working on the lab in class so that people can make sure that their calculations are on the right track and then start the review process for the exam.

Physics G completed the calculations and write up for their heat labs, and engaged in an overall discussion of the results. Make sure that you bring your questions to tomorrow for the exam review.

Homework

Honors Physics A: Ranking exercises worksheet
Physical Science B and E: Practice test for waves
Physics F: Complete lab write up and prepare questions for tomorrow’s exam review
Physics G: Complete lab write up and prepare questions for tomorrow’s exam review