Oh No! Snow!

Every year I hope and hope that we'll have a snowless winter - something that would suit my Southern blood perfectly. And every year, my hopes are dashed. Stupid Mother Nature...

Honors Physics reviewed the elastic, inelastic and perfectly inelastic collisions and then jumped into a mish-mash of problems that require the use of skills dating back to the beginning of the course. Such is the way of physics…keep in mind your studies of kinematics, conservation of energy, projectile motion and make use of any tools in your academic tool bag to jump on these problems. We’ll go over them on Monday, but the link to the solutions are still on the blog post a few days ago. General review after we discuss these problems and then exam on Tuesday.

Physical Science B completed their overview o f buoyancy with a discussion of the homework questions. It was good to hear people thinking in terms of forces and pulling together succinct answers for the questions. We then turned our attention to Bernoulli’s Principle – the pressure in a fluid is inversely proportional to the velocity of the fluid. We linked this to conservation of energy, which we will take up in more detail in the next chapter. Bernoulli’s Principle combined with the nature of fluids to move from areas of high pressure to areas of low pressure has some interesting effects that we observe in daily life, like smoke rising up a chimney, assisting in flight, allowing perfume atomizers to work, etc. A few examples of Bernoulli’s principle were demonstrated in class. Note to parents: I am not responsible if your child goes home and sprays water all over your house to show you what he/she learned in school today.

Physical Science E conducted a lab investigation on buoyant forces. Students directly measured the apparent loss of weight by an object submerged in a fluid, the weight of the displaced fluid and calculated the theoretical buoyant force using the volume of an object and the density of fresh water. Groups obtained good results: the apparent weight loss was close to the weight of the displaced fluid which was pretty close to the calculated buoyant force. It was clear, based on the direction of the net force acting on the object, why the 500-gram mass and rock sank, but the wood floated. On Monday, we will discuss Bernoulli’s Principle. For both B and E Blocks, start looking for a test at the end of next week. The likely day is Thursday, but if people need more math practice, we might have to move it to Friday.

Physics F and G discussed the types of collisions in which objects can engage and how well kinetic energy is conserved in each type. Elastic collisions are good at conserving kinetic energy, but most collisions show definite kinetic energy losses due to deformation of objects, sound production, and internal energy increases. Assume in problem solving that if a collision is not elastic (pure conservation of kinetic energy, objects separate after collision) that a collision is perfectly inelastic (objects stick together as a single object and demonstrate kinetic energy loss). On Monday we will begin reviewing for the momentum exam, which looks like it is going to fall on Thursday, so take time to review the chapter this weekend and pull together a list of questions that you would like to go over next week.

Homework

Honors Physics A: Chapter Review items #27-30, 32, 45, 46, 52, 54, 57
Physical Science B: None
Physical Science E: Complete lab write up
Physics F: p. 230 #2,4 and Chapter Review #27-31
Physics G: None