Blog Post 2-15-12

Good morning NTSC'ers:

I hope everyone is well.  It was my impression that people understood the intent and goals of yesterday's lab.  I am hoping that is true!  And not just deceiving myself.  Here is a couple of items that, I think, underlay the work we have been doing.

1-We have been using models quite a bit and that is very common in scientific endeavors.  The natural world is a messy place and we are saddled with making as good approximations of natural processes.  That has not been to bad a place to be so far; the only "natural" data that we collected was with the sandbags and that was a pretty controlled setting.  To be explicit, the Walking Man is certainly a model and we have used that to understand how to use different equations related to motion, understand the difference between instantaneous and average velocity, understand constant acceleration and interpret graphs of distance, velocity and time.  You should start to feel comfortable with all of these terms and concepts.

The other model we have been using are graphical - a good model for constant velocity is a straight line model (y = mx + b) where m = velocity.  For constant acceleration, the best model is a curve (exponential) line that reveals that velocity is increasing as shown by the steepening slope of the line.  I wonder what a plot of changing acceleration looks like?

2- The second item is to keep our eye on our process - that is the process of science.  While you are working do some metacognating.  Think about where you are in your intellectual process: are you asking questions?  are you collecting data?  or reflecting on findings?  How about communicating?  I would like to think that a fundamental outcome from our work  are experiences with doing authentic scientific work, that is breaking out of our experiences with more linear thinking and doing into a mode of more divergent and non-linear process.

Tomorrow in class we will go more vertical.  We have been exploring horizontal motion, which is easier to observe and measure.  Now as we go vertical we have objects that move at a much higher velocity (is it a constant acceleration?) and therefore harder to measure.  This was a fundamental problem with early investigators (Aristotle, Galileo) who lacked the technology to make accurate measurements.  We will explore new models (equations) that we can use to understand vertical motion (called freefall) and use technology to document our observations.  After freefall, we will start to look at Newton's Laws of Motion that provide the framework for understanding motion, at least on the macroscopic scale.

See everyone tomorrow.

Thanks

Matt