Cuesta College, San Luis Obispo, CA
Students have a bi-weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.
The following questions were asked on reading textbook chapters and previewing presentations on electromagnetic waves and redirecting light (reflection and refraction), along with advice from students from the previous semester, and videos on the flipped class mode of instruction used in this course.
Selected/edited responses are given below.
Describe what you understand from the assigned textbook reading or presentation preview. Your description (2-3 sentences) should specifically demonstrate your level of understanding.
"Visible light (what our eyes can perceive) only takes a small portion of the electromagnetic spectrum and the rest can only be recorded through the use of certain instruments."
"That wave speed and wavelength are affected by change in medium but how frequency is not. Previously I didn't quite understand why but it makes more sense when you say it, because it's from a source (I thought of it like a projector or flashlight being the source)."
"One thing I did understand was the independent and dependent variables for electromagnetic waves. The wavelength is dependent on the speed and frequency of the waves. The speed is independent and set by the medium and the frequency is independent and set by the source."
"Light changes its speed as it passes through different things. The index of refraction helps calculate the speed. Light travels quickest through a vacuum and slower through other materials."
"Indices of refraction describe the speed at which light moves through a medium. In a vacuum n = 1 and the speed of light equals the maximum. In other mediums, light moves slower and n > 1."
"That reflection is light bouncing off a surface where refraction is light bending because it travels through materials with different indices of refraction."
"There are two ways to redirect light, one is to reflect the light which means that the light will bounce off the surface and leave at the same angle in which it first interacted with the surface. The other way is by refracting the light."
"If light travels from smaller refractive index to larger, the refracted ray is bent towards the normal. If on the other hand, light travels from larger refractive index to smaller, the refracted ray is bent away from normal. this relationship is known as Snell's law of refraction."
Describe what you found confusing from the assigned textbook reading or presentation preview. Your description (2-3 sentences) should specifically identify the concept(s) that you do not understand.
"How a light wave has the same frequency as it travels from one medium to another medium."
"When it came to refraction, I was having a difficult time comprehending the concept behind Snell's law. The equation shown did not help much with the explanation, but the simple 'fast-to-slow' and 'slow-to-fast' phases helped get the point across bluntly."
"The 'fast-to-slow' and 'slow-to-fast' phrases were a bit confusing. Although it was mostly trying not to mix them with each other."
"Snell's law came off a little bit confusing since the concept makes sense, but applying numbers kind of throws me off, so some examples in class might clarify my concerns. The index of refraction equations make sense, however some examples in class would be helpful in getting a better understanding in solving. Essentially the ideas make sense, but once they are thrown into math-like equations, I can have a hard time translating, so tutorial-like demonstrations can help clarify the transfer."
"Refraction is a little confusing for me, just being able to comprehend what is happening. I know what refraction looks like in different scenarios, but I have a hard time with being able to understand what exactly is happening with the light."
"I experienced difficulty trying to interpret the Snell's law slides. I was hoping the diagrams that accompanied the laws would be beneficial but I don't think I completely understand their relationship or where sine comes into play. I could use so extra time in class explaining this law."
air. ******************************** [32] water. **** [4] (There is a tie.) [0] (Unsure/guessing/lost/help!) ** [2]
(Only correct responses shown.)
speed v: decreases [71%]
frequency f: remains constant [63%]
wavelength λ: decreases [50%]
For the above example of light incident in air being transmitted into plastic, __________ has the greater index of refraction.
air. ***** [5] plastic. **************************** [28] (There is a tie.) [0] (Unsure/guessing/lost/help!) ***** [5]
(Only correct responses shown.)
speed v: increases [53%]
frequency f: remains constant [66%]
wavelength λ: increases [58%]
For the above example of light incident in plastic being transmitted into air, __________ has the greater index of refraction.
air. ************************ [24] plastic. ******* [7] (There is a tie.) [0] (Unsure/guessing/lost/help!) ******* [7]
State your preference for denoting the inverse sine operation.
Arcsin. * [1] sin–1. ***************************** [29] (No preference.) ***** [5] (Unsure/guessing/lost/help!) *** [3]
Pick one piece of student advice from the previous semester, and discuss why you agree (or disagree) with it.
"'Stay on top of homework!' After taking Physics 205A last semester I definitely agree with the advice of doing all the work and coming to all the classes. Even if you understand the concepts, there's still more to build upon in class."
"'Always, always do the work. It's easy points and can make the difference when passing the class.' Don't procrastinate because things can really pile up which can be overwhelming. Also don't forget to do the homework because they are a fairly easy way to earn points."
"'Don't give up early on.' Physics is a tough subject and quitting will not get me anywhere. Their advice on doing the homework, going to class and to do the labs are helpful. I was doing the same thing in Physics 205A and it helped. I will try and take their advice and get study buddies to better understand the material and work together to figure out the problems. They stated to learn the website and I have been. It was confusing to first but mainly because I was not used to it. I think I have it down for the most part."
"'Try to ask questions.' My regret from last semester was having a lot of questions but never raising my hand in class when I had concerns. I also think it's important to stay on top of the homework rather than categorizing it as a second thought and waiting until 10:00 PM to do it just hours before it's due."
"'Practice, practice, practice solving all the example problems given to you. Also, it helps a lot to write out short answers on what you did.' Last semester I struggled with short answers, so I think writing them down as I do the practice problems would help a lot by the time the exams come around."
"'Actually do all the assignments because they do help a lot. I noticed that when I did the reading and homework assignments it was a lot easier to follow the next class.' I agree with this student because last semester I didn't do all the homework and I would be so lost. The times when I would try to catch up on it all, it would be too late to turn in assignments."
"'Disregard trying to read the textbook and read the blog posts carefully instead because the book is not user-friendly.' I disagree--I find the textbook helpful. It may not relate to this class as much as the online lectures, but reading the textbook before helps me familiarize myself with what the lecture is referencing. I think I will remember more if I continue to read the textbook as an introduction to topics and use the lecture to dig deeper and solidify my learning."
"'Read everything on the waiferx.com course website because there are no reminders and it is not organized like Canvas.' I agree with this comment. It took me a while to get used to understand the format of this class, so missed out on a lot of points I would have easily earned."
"'I suggest the future students take notes while reading (the night before lecture), to better understand the material. Take notes again in class!' I agree with this piece of advice a lot. Partway through last semester I started taking notes on the material I was reviewing before lecture and it really helped my comprehension during the next class period. The information was fresh in my mind and my notebook plus it helped me have confidence knowing at least a little bit about what we cover in class."
"'The grade you get is how much time you put in.' This is probably the most universal advice I've read on the page. It encompasses all aspects of being an effective student, and has rung true for most of my academic career."
Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"What are all these angles about?" (All these angles are necessary to measure the directions and changes in directions of light rays--which is what optics is all about.)
"How different is the 11th edition textbook from the 10th or 9th editions? Can a student get by by using an older version?" (The primary difference is the re-numbering of the end-of-chapter problems; you should be able to get by if refer to a classmate's current edition and renumber the problems by hand in your older edition.)
"How exactly do your lectures go? My previous instructor would just go over presentation slides, and the class felt repetitive." (Class is pretty fluid in terms of allocating time between presentation slides, lectures, examples, worksheets, and problem-solving; it all depends on what level of understanding/comprehension the class has and what level of introduction/challenges the class needs. Typically Physics 205A last semester had some review of a presentations slides and introductory lectures, with mostly a mix of examples, worksheets, and problem-solving.)
"I will say at first I was skeptical of the flipped classroom structure, but I have to say I very much enjoyed last semester and it is one of my favorite learning styles, because I learn best by doing it myself at home, such as going over the notes and doing the problems. This in turn has helped me in other classes."
"How was your winter break?" (It was quite relaxing. Hope you enjoyed yours as well.)
"I hope this is another great semester!" (I hope so, too!)
"I'm sorry P-dog but believe it or not, the beginning of this particular semester is actually difficult. But I can reassure you that I am still a hardworking student!"
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