Day 147: Charge Assessment and Work(ing)

Well it is the Monday after prom… ’nuff said’ right?  No surprise that most of my students became more sluggish as the day progressed.  So here is what we did.

The Advanced course took a ‘Charge Processes’ assessment.  I’m trying something new this year … rather than a summative test on charge; Coulomb’s Law, Electric fields and Electric Potential, I’m going to go with a few short assessments and skip the nitty gritty on how we transition from electric fields to electric potential.

SIDEBAR:  Part of the decision to do this is based on how far ‘behind’ I am from previous years.  We have lost sooooo may days for this, that and the mandated testing, that I am scrambling a bit to cover what I usually do.

Here is the assessment they took today.

Essentially it is straight out of Arons.  I really like it.  After the assessment, I allowed them to work in small groups to finish a practice set on Coulomb’s Law and then prep a WB for tomorrow.

General Physics:

Today we developed the model for work(ing).  I followed the same basic discussion approach I did with the advanced students I wrote about here.  The only real difference is that we do not talk about power right away.  It has been my experience that even though power is not a very difficult concept, sometimes piggy-backing the two concepts leads to confusion for these students.

Day 142: How Hot Are Your Hot Wheels?

The class did two things today, well, I did one and the class did the other.  We discussed the conceptual part of their summative impulse and momentum test.  All of my tests have two components; a conceptual part which is mostly multiple choice (at a higher DOK than simple recall) and a problem set.  The conceptual part is usually about 10 or 15 MC and there are usually one or two problems depending in how many objectives being assessed.  On this recent test, there was an impulse problem and a conservation of momentum problem.  On each test I also provide an opportunity for the students to really challenge themselves by providing a choice of two problems that both address the same objective.  For example, on this recent test the student could choose to do a pretty standard run-of-the-mill explosion problem or a ballistic pendulum problem.

This time we did not discuss the problems.  Rather, I am going to have the students make corrections on the problem(s) they will re-assess in addition to some posted practice problems.

After discussing the multiple choice component we moved to WB’ing the practice sheet putting all the components of the charge model together. We really did not get so far, only through the series of pictures to explain charging by conduction. We will finish it tomorrow.

General Physics:

We had a practice COE assessment and the started a COE activity that has two parts.  The activity is based on this problem from the assigned practice:

The basic premise is whether or not 10% dissipated is a realistic value.  To test it, we are using Hot Wheels and track to recreate the problem.  Essentially, they will solve for the Energy dissipated by taking the difference between the initial gravitational energy and the final kinetic energy.  The velocity is measured at the bottom of the track/ramp with a photogate.

The follow-up will be to have the students use the values from this part of the activity to predict the velocity of the car at some spot along the ramp that I place the photogate.