# Day 61: 30 Minute Classes–again

The day before Thanksgiving break and we have an early release for students and a PLD for the staff.  This means 30 minute classes in the morning, and meetings in the afternoon.  The afternoon meeting included an overall of the philosophy of our Reading Specialists (~20 minutes) and then more information from our LMS expert about Schoology, our districts (purchased) LMS.  I really like Schoology as an LMS.  It is worth taking a look at if your district is not using one or is looking for a different one.  The rest of the tie was departmental so we worked on re-evaluating the benchmarks for each course (even though we are not quite ready for SBG) and assigning a DOK (Depth of Knowledge) to each, then planning common assessments for each.  One of the things that came out of the discussion  I was part of was that there is much work to be done.

So with 30 minutes, what did I do in my classes?

Advanced Physics:

Discussed the problem set from the Projectile Motion assessment.  I always re-write each problem so my students can keep them, and everyone now and then I screw up.  Here is an example:

1.     Remember the angled Monkey and Hunter demo? Imagine that I wanted to use the Mini-launcher rather than the blowgun (I know, not nearly as cool, but…). Some details:

·  It is aimed up at a 30o angle.

·  It’s the third setting, so the launch velocity is 5.20m/s

·  The monkey hangs at a height of 1.25m

If the monkey is to be hit when it is 15cm above the table, how far away, horizontally, should the mini-launcher be placed?

If one solves it by finding the time it takes the monkey to fall to the 15 cm height, the time =0.473s, if one solves if find the time it takes the monkey to have a change in height o 15 cm, the time is  0.464s, and it one graphs it (or solves it kinematically), the time is 0.48 s and the two collide at a height of 11.8 cm.  I was perplexed by this so I sent it out to a few colleagues from of Phox Share group.  One of them replied (4 times) and in the ned realized my mistake.  The monkey and hunter demo makes two assumptions, (1) the two are released at the same instant, (2) the hunter aims at the monkey.  The 30o angle is does not aim at the monkey when it is at a height of 1.25m, it’s close which is why the times turned out so close.  I proposed this to my 3 sections and asked about the problem.  One student in my mod 2 class saw it right away! AWESOME learning experience, and nice for all the students to see that I still make mistakes too.

General Physics:

We reviewed the ramp lab and then used the same video analysis sequence I used with my advanced kids to transition from position and velocity graphs to acceleration graphs.  Al qualitative right now.

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