# Days 101-109: Playing the Catch-up Game yet Again

WOW, falling a bit behind here, I hate that! Almost two weeks since my last post, that’s bad… well enough ‘poor me’ BS.  Rather than give a day-by-day post, I’ll give the highlights…. well, highlights as I see them.

When I last posted I had used a Schoology Poll to see what problems from our Radial force and acceleration practice sheet they wanted to see.  It worked only so-so because no all the students voted. I do think I will try it agin though.

The UCM summative test followed the next day.

Into the next Unit– energy.  I used this problem to introduce it:

I used it to generate a need for our energy concepts — this is a really long ass problem using kinematics and dynamics, but pretty short with energy concepts.  When we discuss the ‘problem’, the need/desire for a shorter way comes out loud and clear.  This is one of the motivations for energy… I treat it as yet another problem solving approach that the students can use. Much like solving kinematic problems with a velocity-time graph.

We used the wealth analogy to build the basic way we think of energy.. a conserved quantity capable of producing a change in a system… that we can picture with energy pies and energy bars.  I use a snippet of Feynman’s lecture on energy conservation and the ‘blocks’ as an introduction to drawing energy bars.  We even have REAL energy blocks:

The original idea for the energy blocks was shared at one of our Phox Valley Share meetings many years ago.  I have multiple sets so when we are learning the different energy assets, we use them and I also use them with the relationships developed in some energy experiments (for a later post).

We practiced with energy bars and pies, took an assessment, then did an experiment looking at the relationship between the force exerted on a spring and the change in length of the spring.  Yep, a Hooke’s law experiment, although that name is not given until we have WB’ed the results. I use the Pasco colored springs sets.. known ‘k’ values to compare our slope to once we have defined it.

This led us into the activity we have been working on for the last few days.  It is an independent research experiment related to Hooke’s law.  Essentially, the students must come up with some change to make and use gathered data to determine how the change effected the spring constant.  For example, maybe two springs in parallel or two in series, how the length of the spring affects the ‘k’ value.  ( I made sets of springs containing 6 springs by cutting up and old snakey spring).

This is what the students are working on right now.  As part of the assignment, they will be creating a presentation to post on our Schoology course page.  They will be required to comment on at least three other experiments.

General Physics:

We finished the balanced forces unit today– summative test.  Along the way, we completed a static equilibrium with tension forces activity.  Using this set up:

the students use the force given by the force sensor (a WDSS) and the angles (measured with a protractor form a picture they snapped) to predict the mass of the candy bar.

We also completed the same frictional force experiment I posted about with the Advanced classes.

Tomorrow, we start the unbalanced forces unit.  We will be doing the Modified Atwood experiment to develop N2L.

OK, so caught up.. not pretty but caught up… at least for now.