Index of Refraction

Honors Physics conducted a lab investigation that examined the change in fluid pressure with depth. The gas pressure sensors were used to measure atmospheric pressure and then the pressure in a column of fresh water at greater and greater depths. The graph of the relationship was very nicely linear and, if you think about the equation for absolute pressure, that makes sense. The y-intercept is the pressure at 0 m depth or atmospheric pressure. Your y-values are pressure, your x-values are depth, the slope is the product of the fluid’s density and acceleration due to gravity (P = P_o + ρgh). This technique can also be used to assess the density of a fluid, if it is not convenient to measure in the lab. Luckily for everyone, the water was mostly contained in the experimental apparatus and no one left the classroom soaking wet. On a cold, windy day like today, that is a very good thing.

Physical Science B went over the multiple choice items of their MCAS review packet. People seemed to do moderately well, but make sure that you clear up any problems by MCAS time. Also, make sure to clear up any issues by midterm exam time. As I said in class, start gathering all the materials you need to study for the midterm exam. Gather you old tests, practice problems, notes packets…the exam is cumulative, meaning back to Day 1 and there is no opportunity for corrections or extra credit. The final is also cumulative, but you will have taken the MCAS prior to that, so the material should be somewhat fresh in your mind. Tomorrow – the ability of a substance to change temperature when it gains or loses heat energy: specific heat.

Physical Science E dove deeper into their discussion of heat energy with an overview of the temperature scales and the methods of heat transfer. We took time to discuss the recent lab activity and relate that to the information we covered in class. As we move into the area of specific heat, there is going to be another round of math, so make sure to have your calculators handy. The MCAS loves specific heat questions and problems, so we’ll make sure that you get plenty of practice.

Physics F and G continued on with their study of forces in fluids with an examination of fluid pressure. Collisions by fluid particles generate pressure in fluids and this pressure exerts forces on objects placed in fluids or filled with fluids. We took time to diagram and describe the function of hydraulic devices and began to explore the variations of fluid pressure with depth. Tomorrow, we will continue on with this discussion in F Block, but G block will conduct lab work on the topic.
Homework

Honors Physics A: Complete lab write up, including the two extra questions
Physical Science B: Complete MCAS open response by next Wednesday; have lab write up for tomorrow
Physical Science E: None
Physics F: None
Physics G: Read lab sheet