For Sherlock Fans

Today, the mini-episode Many Happy Returns aired and it's a wonderful thing and only slightly spoilery...


Also, on the PBS site is Unlocking Sherlock, which is an interesting background video with Gatiss, Moffat and the cast of the show (airs on TV on Jan. 19)...

Remember, in the US, the first episode of Season 3 of Sherlock airs on January 19, after Downton Abbey on PBS. It airs on January 1 on BBC 1, so expect me to be a happy person when we get back to school (it pays to be a tech head sometimes...)

Vacation!

We actually made it in one piece!

B Block completed their lab on levers and most groups also completed their calculations and questions. For the rest, they won't be due until the Tuesday we get back, so you don't have to work in your lab over break if you don't want to do that. When we get back, we start with work, power, machines and energy.

Physics D, F and Honors Physics took their exams and are in line to start fluid dynamics when we return. As I mentioned in class, the wise person might want to check Edline over break. Nothing you have to do, mind you, but something you might want to do.

Have a nice vacation!

Closing in on Closing Time

I was out dead yesterday, so folks worked on completing labs, studying for tests or taking a peek forward to new things.

Intro Physics did the peeking ahead to work and simple machines and began an activity today looking at levers and the concept of mechanical advantage. Folks are looking at all three classes of levers and calculating ideal and actual mechanical advantage for three configurations of each. The lab will finish tomorrow and this is where we'll pick up when we return from break.

Physics D, F and Honors Physics reviewed for tomorrow's exam. We went through the material page by page, highlighting what is and is not fair game for the test and answered questions about the concepts and the math. I'm available before school tomorrow for any last minute issues, so stop in if you need help. When we get back, we start in on forces in fluids.

Centripetal Force and Torque

Physics D and F both worked on lab investigations during their class periods. Physics D used the long block to examine the relationship between centripetal force, tangential speed and orbital radius and Physics F took on the topic of levers. Physics D will get to work with levers tomorrow to round out the unit for circular motion and gravity. We all review on Wednesday and have our exam on Thursday.

Honors Physics went over their rotational dynamics lab and then turned attention to the homework problems for this part of the unit. That took longer than expected, so we'll have to double-up tomorrow and hit both machines and gravity if we want to have review time on Wednesday for Thursday's exam.

Intro Physics reviewed their practice MCAS open response items for force and momentum, then had a focused review for tomorrow's exam on momentum. We'll start with some lab work for our next unit on Wednesday, as we move forward to work and energy.

Motion and Machines

Honors Physics conducted a lab investigation that centered on rotational motion. We looked at torque, angular acceleration and moment inertia for a single spinning disc, two spinning discs stacked together and a lightweight rod with widely-spaced weights. Students measured the angular acceleration for each of these situations for gradually increasing amounts of torque and on Monday, we'll go over the results and what we can draw from them. Then we move on to simple machines for the rest of the period, taking on gravity on Tuesday, review on Wednesday and our exam on Thursday.

Physics D finished their discussion of torque with a look at net torque and the sign of torque and then turned attention to simple machines, which is where Physics F also picked up after their discussion of yesterday's centripetal force lab. We listed and described the six simple machines and discussed how machines manipulate force in either work or torque. We contrasted actual and ideal mechanical advantage, then discussed the concept of efficiency and explained why it is always less than 100%. On Monday, D Block works on their centripetal force lab and F Block conducts an investigation centered on levers. Tuesday is D Block's lever lab, while D Block gets some problem-solving practice with machines. Wednesday is review day and Thursday is your exam.

Intro Physics reviewed their conservation of momentum problems, then had some practice with MCAS items for force and momentum. Folks worked on the multiple choice in class, which we went over before the bell, and have the open-response for homework. We'll go over those on Monday as part of our review for Tuesday's exam.

Things Spinning

Physics F conducted a lab investigation centered around centripetal force, tangential speed and orbital radius. Students varied radii and measured the tangential speed of a rotating body, given a specific (yet varying per trial) centripetal force. It was seen that the greater the centripetal force, for a given radius, the larger the speed needed to maintain it and a larger radius required a greater speed to maintain for a specific centripetal force than a small one. We'll discuss the lab tomorrow, before reviewing our work on torque and moving on to simple machines.

Physics D worked on torque today, by defining torque and looking at how manipulating the variables of lever arm and angle of applied force impacted the toque a force delivered. We practiced working with the torque formula and, tomorrow, we'll add the direction of torque and net torque to our toolbag. Then, it's on to simple machines.

Honors Physics reviewed their homework for rotational equilibrium, then turned attention to odds and ends for rotational dynamics. We looked at Newton's 2^nd law for rotating systems, momentum and its conservation and kinetic energy/conservation of mechanical energy. For the formulas, they are easy to work with from the standpoint that all you have to do is replace the variable in the linear form with its angular analogue, but remember that moment of inertia has its own formula based on the shape of the object. Tomorrow's lab will allow you more practice working with these ideas, and we'll go over your homework problems on Monday.

Intro Physics took the period to practice working problems dealing with conservation of momentum. It is important to properly read through the problem to identify and organize information and use the basic conservation of momentum relationship in a way that is appropriate for the scenario of the problem. Tomorrow, we'll go over these problems and look specifically at how the MCAS approaches the topic of momentum.

Circular Motion

Physics D began their work with circular motion today with an overview of centripetal acceleration and centripetal force. We contrasted tangential and angular speed, then looked at how those different speeds were impacted by tangential and centripetal acceleration. Remember that tangential acceleration works on changing the speed of the motion and centripetal acceleration is involved with changing the direction. We then looked at centripetal acceleration and how many forces can do this job. Tomorrow, we take on the idea of gravity, a force can serve as a centripetal force. This is where Physics F picked up today. We looked at how Newton pulled together the pieces of the idea of gravity and the formula for Universal Gravitation. The homework tonight will allow you practice with this idea and tomorrow we'll jump over Kepler's Laws of Planetary Motion and take on the concept of torque.

Honors Physics concentrated on center of mass, moment of inertia and rotational equilibrium today. We defined center of mass and it paved our way for a discussion of moment of inertia - the resistance of an object to changes in rotation. We looked at how different shapes have different moments of inertia, with the general rule of thumb that the further an object's mass is away from the selected axis of rotation, the higher the moment of inertia and the harder it is for a torque to produce acceleration. We then looked at the two conditions of equilibrium and ended class at the point where we'd begin to look at problem solving, so that's where we'll pick up tomorrow.

Intro Physics took on the idea of the impulse-momentum theorem, using yesterday's lab to highlight our discussion. The impulse an object experiences (force x time) is equal to an object's change in momentum and we looked at how this principle applies to situations involving safety nets/airbags and follow-through in sports. For the same theoretical momentum change, the longer the duration of the situation, the smaller the force the object experiences and for a maximum momentum change, given a limited force, prolong the contact as much as possible. Tonight's homework gives you practice with the math of this concept and tomorrow we'll see how impulse and Newton's 3rd Law of Motion lead to a new concept - conservation of momentum.

Recovering from Exam Friday

Everyone but Physics D had an exam on Friday and today picked up with new material. Intro Physics jumped into momentum with an investigation targeting the impulse-momentum theorem. We looked at the forces applied to a cart by a stiff versus a loose elastic material and how the elongated time of force application reduced the overall size of the force. We'll talk about the lab tomorrow and use it to highlight our introductory discussion of momentum.

Physics D took their momentum exam today and Physics F began their work with circular motion. We introduced the concepts of tangential velocity, centripetal acceleration and centripetal force and discussed examples to highlight these ideas. We then examined the formulas for centripetal acceleration and force and we'll go over the homework problems for these concepts tomorrow in class before moving on to gravity. Honors Physics took a slightly different approach, since they had already covered those ideas, instead starting with the concept of torque. We looked at how lever arm, applied force and angle of applied force affect the amount of torque produced and discussed examples to highlight these ideas. We covered the concept of net torque and previewed how it will involve itself with angular acceleration. Tomorrow,we go over our torque homework, then turn attention to center of mass and moment of inertia.

Investigating Bernoulli and Impulse

Intro Physics worked on a series of activities to illustrate Bernoulli's Principle. The five activities demonstrated the effects of setting fluids in motion and the resulting unbalanced force that results causing a visible change in motion in matter sandwiched between the high- and low-pressure fluids. Tomorrow we'll discuss this lab, go over last night's homework, then review for Friday's exam.

Physics D reviewed their work with collisions then had a general review for Friday's exam. Tomorrow is a lab on the impulse-momentum theorem, which is the investigation Honors Physics worked on today. The lab clearly demonstrated the agreement between the impulse applied to an object and the resulting change in the object's momentum. We'll discuss this lab tomorrow as part of our general review for Friday's test.

Physics F held off discussing yesterday's lab until tomorrow, when it will be bundled with the general exam review. In class we looked at identifying types of collisions, the properties of elastic, perfectly inelastic and inelastic collisions and how to approach them with problem solving. We'll go over the homework tomorrow, also, as part of our exam review.

Rolling on with Momentum

Physics D and Honors Physics reviewed the concept of conservation of momentum, then turned attention towards elastic and perfectly inelastic collisions. We discussed the properties of these types of collisions and looked at how the perfectly inelastic did not conserve kinetic energy, but the elastic type did. Tomorrow, Physics D reviews for Friday's exam and Honors Physics conducts an investigation on the impulse-momentum theorem. This was the lab that Physics F performed today, to very good results. Using the force sensor and motion detector, students measured the impulse delivered on a cart and the cart's momentum change, seeing that the two values were in agreement. We tested different materials for applying impulse and how the nature of the time of the interaction influenced the force delivered. The balloon changed the cart's momentum slowly and the cart experienced a small force. The surgical tubing caused the momentum to change quickly and we saw an increased force because of it. Tomorrow, we'll discuss the lab, review our conservation of momentum homework from Monday and then turn attention to collisions.

Intro Physics reviewed their work on pressure at depth and buoyancy, then took a look at Bernoulli's Principle. When looking at fluids, speed is inversely related to pressure. Given the same fluids and depth, faster fluids have lower pressure than slower moving fluids. We looked at examples of this principle in action and will conduct a series of investigations tomorrow to see Bernoulli's Principle in action. Thursday, we review for Friday's exam...

Back to the Grindstone

Intro Physics, Physics D and Honors Physics continued to hone their problem-solving skills in class today. Intro Physics worked on problems dealing with the motion of objects if fluids, Physics D on conservation of momentum and Honors Physics also took on conservation of momentum, albeit at a more evil level, with all sorts of twists and turns thrown in. Tomorrow, Intro Physics moves to Bernoulli's Principle, which addresses fluids in motion and the pressure they experience. Physics D looks at elastic and perfectly inelastic collisions, as will Honors Physics. Exams on Friday for everyone!

Physics F were introduced to the idea of conservation of momentum and its relationship to Newton's Third Law of Motion. We linked impulse and momentum change to the law of conservation of momentum, then began to apply this law to different situations in problem solving. Tomorrow, a lab on the impulse-momentum theorem before turning attention to collisions. You also have an exam on Friday, so make sure to prepare accordingly.