# Talk:Waves

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# Response to Checklist

You've done some great work on this page, but there are some areas that still need some work. See my comments below in red AnnaP 16:07, 15 July 2011 (UTC)

## References and footnotes

• All images no matter I created or borrowed, I left messages. But for two images I searched from google that I cannot find the author, I just leave the url.
• Direct quotes from textual sources are cited.
• References for text are at the end of the page, with links.

## Good writing

### Context (aka Generating interest aka Who cares?)

• The page I made it specificly for middle school kids & high school kids, who have a basic idea what trigonometric function is.
• I do think that you could use a bit more information in the Why It's Interesting section. How about adding something about other things that are waves, like earthquakes?
Flora 16:55, 15 July 2011 (UTC)I moved the application section to Why Interesting, and also added some information and images about earthquake. I hope this will be better.

### Quality of prose and page structuring

• At beginning part, I introduce the graph of sine wave, and talks a little bit history about it.
• The purpose of each section is clearly relevant to the purpose of the page as a whole.
• I don't have a specific thesis, I just follow close to the titles of the sections.
• Within the "More Mathematical Expalanation" section, the heaviest math is placed as late as possible within this section. If readers see math they don't understand, they may simply skip the section entirely instead of looking later for material they do understand. I hide each subsections, so that readers can choose which section they want to look at.
• I feel like your section on Sine curve properties needs just a bit more. Can you give an example of why the sine function is odd? Maybe make a picture of the graph and label corresponding points (say sin(2) and sin(-2) ) to explain the idea of an odd function better?
Flora 18:42, 15 July 2011 (UTC)I realize that this section may make confusion because of the title. I talk specifically about property of being periodic and odd. So I change the title to Periodic & Odd. Also I added two balloon to explain periodic and odd. Actually a function is odd means that $-f(x)=f(-x)$. I hope it makes this section better.
• Your "Translate Trigonometric functions" section doesn't fit very well. While it's interesting that you can write all of the other functions in terms of sine, I'm not sure it fits on this page. All of your description of the sine curve is for functions that are linear in sine, yet when you write the other functions in terms of sine, you get non-linear equations, which will end up having different properties when you graph them. So, I think you could get away with just cutting this section.
Flora 17:16, 15 July 2011 (UTC)I deleted this section.
• You need some more text in your section on Sinusoidal Waves In Fourier Series to explain why that's useful and why it fits in the page.
Flora 18:24, 15 July 2011 (UTC) I add some explaination in front of this section, and I will try to add image for this.

### Integration of Images and Text

• Wherever an image or animation is used to help with an explanation, the reader is explicitly instructed to refer to the image.
• The text explicitly points out what the reader should observe in a picture.
• When you talk about getting the other functions through Fourier series, can you create images to go along with them? For example, if you plot the first two terms of the series, you get something that's sort of like what you want. If you plot the first five terms, it looks quite a bit like what you want, and if you plot the first 20, it's a very good fit. That explains why they can be used even without taking the sum to infinity. Creating those plots in Mathematica or Matlab shouldn't be too hard

Flora 18:25, 15 July 2011 (UTC)I added image for non-sinusoidal waves. I will try to add images for sine and cosine also.

### Connections to other mathematical topics

• Wherever possible, relationships between the content of this page and of other topics/ideas in mathematics are identified and explicitly described. I made a section see also, and put related topic pages there.

### Examples, Calculations, Applications, Proofs

• I put bunch of images to help reader understand what I am talking about.
• Do not have difficult proofs.
• Have application but a section still need future work.
• In your first example, when you compare the two graphs, can you make sure that you list the two functions in each graph above each graph instead of below? That'll make it easier for the reader to follow what you're doing. Also, you're calling several different functions f(x). You should give them different names. You can let your original function be f(x) and then refer to it as f(x) instead of "the original function." You can then call your other functions g(x), h(x), etc.
Flora 17:13, 15 July 2011 (UTC)Thank you for your suggestion. I have fixed this

### Mathematical Accuracy and precision of language

• The goal is always that all statements, equations, and mathematical terminology are free of errors.
• Statements are made as precise as they can be without overwhelming the reader with too many words or dense symbols (and are always precise enough to rule out major ambiguity).
• In your General form of a sine wave section, you don't define $\nu$. Add another bullet point to do that.
Flora 17:09, 15 July 2011 (UTC)Sorry, $v$ should be $c$. I have fixed that.
You still use $\nu$ under "Useful formulas transformed by a general sine function:" so it needs to be defined.
I'm sorry, all the v should be c. I have changed them.
• In your non sinosoidal wave section, make sure to define things like the floor, duty, saw and sgn functions. I'm familiar with floor, even I am not familiar with the other ones.
Flora 18:22, 15 July 2011 (UTC) I fixed this part. I explain what floor is first, and try to avoid duty and saw. Delete sgn function part. I hope this is better.

## Layout

• Text is in short paragraphs, and broken up by relevant images throughout.
• have bunch of hide and mouse over items.
• To whatever extent possible, pages do not have large, awkward chunks of white space.
• When text wraps around images, images don't force dramatically different "margins" for consecutive lines of text.
• No image in one section of a page vertically aligns with the text or a heading of a different section.
• In hidden text, none of the preview text appears as weird computer code (see Wiki Tricks for help on this).
• The page has been viewed at a few different window sizes to make sure funky things don't happen.

# Discussion

Hey, my name is Kate. I saw this page on Recent Changes, and I just wanted to let you know that a couple of us here at Swat have been working on related topics. Richard's written a page on the Law of Sines, and Harrison and I have been working on a page called Basic Trigonometric Functions. Looking at what you've got so far, it looks like you're focused on graphing and transformations, which we didn't talk about, so it looks like our pages can fit well together. I'm going to add a link to this page on the Basic Trig page, and I was thinking maybe you'd like to read through our pages and do the same? -Kate 20:23, 31 May 2011 (UTC)

Can't wait! -Richard 6/8

Flora 16:51, 13 June 2011 (UTC) I have changed the links, you can see if that works.

Hey, Flora,

Have you given anymore thought to the title of the page? We figured a better way to rename pages I think. Send me an e-mail and I can get better instructions for you.

Richard 6/23

• You do a really great job at going through and introducing all the different types of waves.
• You're main image is really cool, but you don't really discuss anything further about it in the page.

Because actually the image is too abstract to explain, and it is just a random graph of a sine function. I use the graph of all trig function try to show how trig graphs look like.

• The Table of Contents is way too long. It's less intimidating for a reader to see a page with fewer sections. Maybe consolidate some of the sections.
One way to do this might be to add some of the stuff about periodic functions and sinusoidal waves into the basic description because that's really the math part that you want to describe later?

I fixed this problem by just not use level 1 headline.

• You also have a lot of stuff hidden. If it's something that's only a sentence long, like when you have "Click to reveal the detail", I think it's just as good to keep it unhidden.

I fixed this

• It seems like you have a lot of bolded words that don't need to be. ex: "mathematics", "transfer of energy" in basic description. You've also got some that should be bolded or a mouseover. ex-"equilibrium" in the mechanical waves section. Think of what words you would define in a glossary, then bold/make a mouseover for them. That's how I think of it at least...

I tried to fix some of them, and use some bubble to explain words.

• There's a lot more you could do with the Why It's Interesting section: you talk about ocean waves earlier and that might be able to make for some cool pictures/diagrams.
• Law of Sines and Law of Cosines should probably not be in the see also section. They are more about geometry.

Fixed

• A lot of your references are from Wikipedia.

I fixed some but not all of them, I will look up for some better resourses.

### Intro

• The opening sentence might say "function" or "composition" instead of "combination".

Fixed

• Make the intro more inviting, something to hook the readers in, something really interesting. The Monty Hall Problem has a really good one.

### Basic Description

• I was confused by the first sentence of the second paragraph. Maybe make it more basic? (I've never really had physics other than basic mechanics so I might not be the best judge for this)  ::"One type of wave is a mechanical wave, which propagates through a medium in which the substance of this medium is deformed."

• You've got some pronoun confusion here. Which things are you talking about?
When air molecules collide with their neighbors, they also bounce away from them (restoring force).

I changed this part to more mathematics, and move the physical wave down to the application part, I hope this works.

### MME: Mechanical Waves

• I think a picture would be really great when you talk about transverse and longitudinal waves. Use the ocean maybe? It adds an element of fun.'
• Delete the second "here":
"Even though the waves discussed here will refer to travel in a medium, the mathematics introduced here can be used to analyze properties of non-mechanical waves."
• The subsection "what cause a wave" should be "what causes a wave"

I put this part in application, and I'll try to find a picture to show the wave.

### History of the Sine Curve

• Instead of having that sentence at the end that says "for more information...", maybe make a blue link for the word "sine" earlier on, like this sine. The code is [[Basic Trigonometric Functions|sine]].

I fixed this, I put the trigonometric link in front of the history part.

### Basic Graph

• I think you should define it as a periodic function right up front, maybe in the initial paragraph next to the figure.
• I'd combine this with the section below.

I put this section with history section to the basic description, because they are easy to understand

### General Form

• I don't think "sine function" should be bold here.
• Is there more on wave speed?
• In the Frequency definition, it's not clear what a cycle is.

Fixed

### Change the Amplitude

• Bold range. And isn't it the range related to amplitude mathematically?

Fixed

### Change of period

• Don't hide the detail.

Fixed

### Change of Phase Shift

• Delete "This is what is happening here."

Fixed

### Sine Curve Properties

• This section might make more sense before you talk about the graph.

Fixed

### Other trig functions in terms of sine

• long section title.

Fixed

• What are the other useful equations and why are they relevant? I'd describe them?

actually they are formulas transformed by a general sine function. I moved them to general form section. I hope that makes more sense.

### Fourier

• Combine the fourier series section and the sinusoidal waves in fourier series section. It could help with the TOC.
• This section was a little confusing to me.

# Waveforms

Flora 16:51, 13 June 2011 (UTC) I will add some explaination to the waves, and what is non-sinusoidal waves. And some explaination about the graphs.

# Sine Wave Generation

This part is what I need to work on most, but physics is kinda difficult. I will try to revise later.

• You've done a nice job explaining waves so far. My comments are sometimes just minor and additional suggestions. It's okay if you don't agree with me.
• You might want to be more consistent about when you use math font and when you use regular writing.
• I know you've fixed some, but I still can see a lot of references from wikipedia. Try to avoid using wikipedia for your other pages.
• You have a lot of hidden contexts. Sometimes you don't need to hide them. If you want to show us the structure of your page, we can just look at the content.
• If there are some minor grammar errors, I just edit them for you.
• Like how you arrange the pictures and contexts. I don't feel the page crowded.

## Intro & Main Image

• The main image is awesome. Intro is simple and clear.
• Love the name "Flame," very vivid. Maybe you could change The creator of this image calls it "Flame". into This main image is called "Flame." to make it more like an introduction. It's really minor. No big a deal.

Fixed

## Basic Description

• The first line "phenomenon" should be "phenomena (pl)." I changed it for you.
• I think it is a good description. The only thing I might suggest is that you can make the figure - circle- a little bit bigger.

### Basic Graph of the Sine Function

• Note that some people may not know what $\varphi$ means and you haven't shown us the basic form of sine yet.

Fixed

## MME

### Sinusoidal Waves

• You did a very good job explaining the symbols. I think you could add an image showing how to tell the amplitude from a graph, which part is the wave length, and so on. It makes it easier to understand and remember.
• You could add more things to illustrate the sine curve in one dimension and 2 or 3D. I feel like you didn't discuss this part thoroughly. If they are complex, consider give us simplified pictures. Any way you like, but please talk more about this part.

I will leave a message for future direction, because I don't think I have time to make more.

• The second useful formula :$y(x,t)=A \sin 2 \pi(\frac{t}{T}- \frac{x}{v})$. I assume you got it from the first formula and change $f$ into $\frac{1}{T}$. Then shouldn't it be like this: $y(x,t)=A \sin 2 \pi(\frac{t}{T}- \frac{x}{vT})$ ?

Fixed

#### Sine Curve Properties

• Inform the readers what $I$ in $k \in I$ is.

Fixed

Should't integers be denoted as $\mathbb{Z}$?
• You don't really need the three bullet points here. The equations has already stood out.

Fixed

• When you say "Both functions are created ...", which two functions are you referring to? Try to make it clear that you mean these two $sin (-x)$ and $- sin(x)$.

Fixed

#### Explore The Graph of Sine Function

• Alright, I'm being picky again. :) Did you notice that the three graphs are in different sizes? And the third one is stretched so much that they are barely "curves."

I'm sorry about that, but it is too hard to change it. I made the image on Derive, and the graph itself is not very clear. and if I want to show the change, I have to magnify the image.

It's totally fine.
• Change of the phase shift section: To make it more complete, tell us how can you tell if it will shift to the right or to the left by checking the plus or minus sign "+" "-".

Fixed

#### Translate Trigonometric Functions

• Too much white space here. Consider using a table or columns.

Fixed

• To be honest, I don't know why you list those equations here. Just for reference?

I add some explanition. I just want to say that every trigonometric function is a sine function, so we do not need to study all of them.

#### Graphs of Other Trignometric Functions

• I suggest you make the cosine graph bigger or it is good as it is now.

Fixed

#### Non-sinusoidal Waves

• I feel like you could add more explanation about these three graphs.

I add this suggestion to future direction.

## Fourier Series

• I don't think Fourier should be boldfaced here. It's just a name not a math term.

### Sinusoidal Waves In Fourier Series

• Those "fancy" equations are confusing. You may need more words to explain them. Make sure that everything you have on the math page is understandable and clear otherwise don't put them on.

### Non-Sinusoidal Waves In Fourier Series

• Same. The equations are confusing.

# Application of Waves

## Waves In Nature - Mechanical Waves

• The first sentence: Physical waves, or mechanical waves, form through the vibration of a medium, be it a string, the Earth's crust, or particles of gases and fluids. What does '"be it a string" mean?
• This article introduces these wave properties, but will not address how to apply them in specific situations in physics. This article? I think you don't really need this sentence.
• Like What Causes A Wave section.

Fixed