This unit is a response to the need to clarify some of the basic language we will be using in this course.
In the event that any external links are broken or outdated please let me know as soon as possible.
At it's heart physics, like pretty much everything, is a search for rules that we can reliably use to predict what will happen in some circumstance. The link above provides a visual representation of how this search for rules takes place in physics (this particular form is the ISLE process).
The core idea to think about is whether it is possible to know that any rule is 'True' (as in can't be wrong) using this process? The first 11 minutes of this commencement address from Tim Minchin contains some excellent advice along with a succinct definition of science that both answers this question and aligns with the ISLE process.
We all build models of the world to help us understand and anticipate what is happening around us. We often meet people who have different models of the world than we do which is often described as 'seeing the world differently'. Models are important in helping us represent the world we are trying to understand without overwhelming us with complexity. Models are typically simplified versions of the world with limitations that we have to understand. The article linked above will give you a good sense of how models are used in physics.
Activity: What is a model that you have about the world?
People often think of physics as being a scary form of mathematics and while there may be some truth to that dimensions and units are one of the fundamental differences between science and pure math. Everything in physics seeks to describe some measurable feature of the universe and as such every mathematical symbol has dimensions/units attached to it because of what it describes. Dimensions/Units are a tool for checking the validity of an expression or result. Because of this it is important to keep track of units as we work in physics and to distinguish between fundamental units and derived units. Temperature, distance, and time are examples of fundamental units. Force, density, and energy are examples of units that are constructed from the basic units. For this class we will work entirely in the ISU (metric) system so if you are not familiar with the ISU please explore them a little.
Activity: What basic units make up the units for acceleration? Start with the definition of acceleration from MTH 251 and consider the units upstairs and downstairs.
HW: Concepts
Using data derived from your personal experience determine the density of snow in kg/m3. Provide sketches and estimated meaurements along with all conversions needed to make this determination. Provide the data for which you believe this calculation is valid. Compare your result to the density of water, 1000 kg/m3 and balsa wood at 160 kg/m3 and justify the reasonableness of your answer.
Unit Conversion like a physicist:
If you need a reminder of the sort of thing we are doing with unit conversions then this video may be helpful. If you have taken Chemistry with any of our COCC faculty the ladder method of unit conversion you used is essentially the same and is welcome in this class.
HW: Concepts
Convert 30 m/s (65 mph) to that classic British unit - furlongs/fortnight. Make this conversion through a series of individually simple conversions some of which you will need to look up. m to furlongs will not be considered a simple conversion.
[1.80.105 f/f]
In physics and engineering we use conceptual and mathematical models to attempt to describe the world around us. The effectiveness of our models is tested and confirmed by how well they match the observed behavior of the world. In the end, the precision of that agreement is very important. In math classes problems generally have a very specific answer. 2 + 3 = 5 and not 5.3. All of this leads to a natural tendency to keep track of many digits in our calculational work. The underlying reality is that, except in mathematics, all numbers ultimately represent a measurement and have some level of uncertainty. When we use those numbers in a calculation we need a way to keep track of the impact of the underlying uncertainty on the result. While this is all important to primary purpose of this class is to develop basic conceptual models of physics that apply in a wide range of circumstances. In most cases in this class we will be unconcerned with high levels of precision. Most of the time if you keep 2 decimals or at most 4 significant figures you will be in good shape in this class. Be aware that if you provide an answer that has an unreasonable number of digits it will be rejected.
HW: Concepts
How many significant figures does each number in the 8x row have? Do all of the numbers in a particular column have the same number of significant figures? Do all of the numbers in a column have the same precision?.
[2,3,5,2,5,2,5,3,3,4,4,no yes]
Physics Problem Solving (I, II):
Here are three perspectives on problem solving in physics. The first is a YouTube which is a good start, the second is a thoughtful though somewhat lengthy description of the same thing with more detail, and the last is my hero's perspective (Rhett Allain) on what we should also be doing. The following method is NOT recommended:)
Homework Format:
Here is the basic problem solving framework we will be using. Expert problem solving is a rich topic for discussion and we will only scratch the surface at this point. The linked framework includes some examples of student work as well as examples of more structured engineering HW formats that will be required in your future. The basic message is to take the time in your homework to be as clear as possible at each step of the process and not to focus on whatever answer answer you think you are supposed to get.
Class Process:
Each year I find myself searching for a better way to both support and challenge you in your learning. I am not a great fan of formal timed tests though I acknowledge that they are a remarkable tool for focusing the mind. Here is how I'm planning to implement this class (at least for the time being).
Explore a topic:
We will (hopefully) begin a new topic each week. I will expect that you have spent some time (at least an hour or so) going through the breadcrumbs for that topic ahead of time and considering the questions that are posed. I will endeavor to use the class time to actually offer questions and problems that are based on the material in the breadcrumbs to develop your understanding.
Each time we gather for class there will be an opportunity to ask questions about earlier HW problems or content from previous classes. I reserve the right to not answer questions if you can't show me some meaningful work on the problem:)
Activities indicated with this label, Activity:, will typically indicate a task that will be done in groups during class time. In f2f classes this will be done with the other students at your table. In a remote classroom breakout rooms are likely. Depending on the available time some of these may be skipped or addressed with the entire class. Feel free to explore them ahead of time on your own.
Homework:
Homework usually follows that development of new conceptual tools. In a standard classroom this would normally be assigned each week for students to work on independently. As part of the redesign of this class for remote learning I have embedded homework problems in the breadcrumbs for each day. Create your solution to those problems and submit it to the LMS as a pdf or other legible document. As you can see in this breadcrumb the homework problems will be identified with a HW: [name] label and problem will be inset from the rest of the text. Your solutions should follow the problem format described above.
Unit Assessments:
Once we have explored a topic and you have completed the homework then I will pose a question for you based on the material. While I sometimes implement this as a quiz the loss of class time is often excessive. As a result these questions are often offered as take home problems for you to work on individually and independently. Like other work in this class your solution should meet all the expectations of physics problem solutions. Once an assessment has been given I reserve the right to ask you to redo the problem (with different numbers) in class without warning and with limited time.
Note that the Unit Assessment takes place roughly the week after you have completed the homework for that topic. Many topics in physics stick around and become part of the baseline for the next topic so you will get lots of practice. My intention is to assure you have some time to work out your understanding before you are 'tested' on it.
Labs:
Labs are a time to explore a topic in an applied setting and take data. There will often be specific challenges embedded in the lab. Your lab reports will be generated in a python notebook and will nearly always involve the production of plots and data analysis using python code. Python notebooks also support LaTeX, a markup language widely used in science and engineering, for the written portions of your lab. Lab reports will be created by each individual student outside of the lab and submitted to the LMS within the week following the lab. We will talk more about lab expectations in lab.
Scientific Abilities:(pending)
As discussed in the grading policy these are broader skills that we are working to learn as we also learn about physics. These include problem solving skills, data presentation skills, communication skills, and skills using particular conceptual frameworks in physics. These skills are embedded in the other activities that are described above. I will generally let you know what part of another assignment I am assessing for your Scientific Abilites in advance but I also reserve the right to adapt to what I see crossing my desk at any point.
Assignment: HW: Concepts
Turn in the various (3) homework problems in this breadcrumb. The full problem solving format is a little bit of overkill for these problems but be sure to organize your work clearly.
Assignment: Reading
Go on to Estimation breadcrumb to move to our discussion of the importance of estimation and a methodology for doing so.
