----- Original Message -----
From: Ann Navin <navina@rpi.edu>
To: <siegmw@rpi.edu>; <craigk@rpi.edu>; <boycew@rpi.edu>; <huebsr@rpi.edu>
Cc: <mannik@rpi.edu>; <navina@rpi.edu>
Sent: Wednesday, March 24, 1999 5:02 AM
Subject: Spring-mass module

> Hello all,
>
> My apologies for sending you two alpha/beta test suggestions so close
> together, but I was unaware that you have two modules--the Spring-Mass and
> the Forced Spring Mass. (sorry Ryan about the HTML thing for the forced
> spring mass module, but these comments really are for Spring-Mass). And Ken
> has the Spring-Mass module listed as one of the "show-off" modules--its even
> making an appearance in a Links brochure. So I thought I should send you my
> comments for this one as well.
>
> It seems that there are some similar suggestions for both your modules, so
> you may be able to kill two birds with one stone (we can only hope). So here
> goes (and, again, this mail is lengthy, but I wanted to be thorough). Please
> contact me if you have any questions or comments: navina@rpi.edu, or ext.
> 6136 in the Links Lab.
>
> Spring-Mass
>
> links.math.rpi.edu/devmodules/mechanicalosc/springmass
>
> Content Developers: Siegmann, Boyce, Craig
>
> Programmers: Huebsch: HTML
>
> General Comments:
>
> *Interesting example of the spring-mass system--the bungee jumper. It would
> be fantastic if you could get a video clip of an actual jump (see the Drag
> Forces module).
>
> *We're trying to implement the next and prior buttons in the side navigation bar
> (please see the Links template for an example:
> links.math.rpi.edu/devmodules/template)
>
> *Modeling misspelled in the side navigation bar (it should have only one "l").
>
> *a question about the term Spring Mass: its hyphenated (Spring-Mass) in the
> title and in this module, but not on Links start page for Differential
> Equations. Is one way correct? Or preferred? Also, should Forced Spring Mass
> be hyphenated then in that module??
>
> *The functional headings (in the functional navigation bar) don't always seem
> logical with the content. For example, most pages with equation derivations
> have a "collaborate" heading. I don't see the connection. Please see the
> help page for a better explanation of how the headings and navigation are
> intended to be used.
> (http://links.math.rpi.edu/devmodules/shared/html/help.html)
>
> *any discover, application or practice pages would also add to this module.
> The discover section is meant to include "experiments" via applets that the
> students can play around with to better understand the concepts. The
> application pages are meant to give examples of real-world applications of
> the concepts--even links to other web sites that demonstrate spring-mass
> concepts are appropriate here (see the Vibrating Strings module for
> examples). The practice pages are meant to have practice problems--even if
> they aren't required as part of the module, they might be good for students
> to have access to as review or extra help.
>
> *beautiful schematics throughout the module!
>
> *great flowchart under the map!
>
> *the crib sheet is for the undamped case only--is there something to add for
> the damped track?
>
> *Is it possible to include a summary section that highlights the main points
> of the lesson and pinpoints the differences between the damped and undamped
> tracks? Many of the pages look identical between the two tracks and students
> might skip over pages thinking they've already seen them, when in reality
> there is new information about the damped spring-mass system. Perhaps have a
> series of practice problems to gauge student's levels of understanding (for
> both your benefit and the students').
>
> More Specific Comments:
>
> *html/start.html
>
> --please format the copyright information at the bottom of the page.
>
> --you don't need the "concepts" heading on this page (its appropriate to
> leave the intro with the functional navigation bar grayed out).
>
> --great image!
>
> --consider changing the second sentence in the first paragraph from : "To
> introduce the concepts of mechanical oscillations we consider the
> spring-mass system, which is simple yet convincing to explore." to : "To
> introduce the concepts of mechanical oscillations, we consider the
> spring-mass system, which is simple yet convincing when explored."
>
> --Consider rephrasing: "One example of a spring-mass system is a bungee
> jumper. In this exciting sporting event shown in the picture, the jumper is
> considered as the mass and the bungee is considered as the spring component
> while the rigid support is a bridge or a tower. In bungee jumping the motion
> is not constrained, which permits motion in more than one direction. In
> addition, there is damping so that the jumper will eventually stop. The
> effect of damping is also investigated in this spring-mass module."
>
> to: "One example of a spring-mass system is a bungee jumper, as shown in the
> photo. In this example, the jumper is the mass and the bungee is the spring
> component, while the rigid support is a bridge or a tower. In
>
> bungee jumping, the motion is not constrained, which permits motion in more
> than one direction. In addition, there is damping so the jumper will
> eventually stop. The effect of damping is also investigated in this
> spring-mass module."
>
> *html/objectives.html
>
> --modeling misspelled in the second bullet point
>
> --again, the functional navigation bar can be grayed out on this page.
>
> *html/introduction.html
>
> --the functional navigation bar can be grayed out on this page
>
> --please amend the phrase "At any time during the module you may access
> either the undamped or damped case by clicking on the appropriate track in
> the upper right hand side of the screen." to something like "At any time
> during the module, you may access either the undamped or damped case by
> choosing a track from the pull-down menu on the side navigation bar (in the
> upper-left corner of your screen)."
>
> *html/physicalsys_theory1.html
>
> --last sentence on the page: "Our physical system is made up of a mass
> attached to a rigid s upport by a spring." Delete the space in the word
> support.
>
> *html/actualbehav_case1_exper1.html
>
> --why is this a "discover" page, when its also in the side navigation as a content
> heading?
>
> *html/physicalmod_theory1.html
>
> --please format the copyright information at the bottom of the page
>
> --for clarity and emphasis on the idea of engineering judgment, consider
> rewording the passage: "The astuteness with which approximations are made at
> the outset of an investigation is the crux of engineering and applied
> mathematical analysis. The ability to make useful approximations that
> greatly simplify the system and still lead to a rapid, reasonably accurate
> prediction of its behavior is the hallmark of every successful engineer.
> This ability is engineering judgment. A list of assumptions regarding
> various aspects of the spring-mass system is given below."
>
> to: "Astute approximations made at the outset of an investigation create the
> crux of engineering and applied mathematical analysis. The hallmark of every
> successful engineer is good engineering judgment, the ability to make
> useful approximations that greatly simplify the system and still lead to a
> rapid, reasonably accurate prediction of its behavior. A list of assumptions
> regarding various aspects of the spring-mass system is given below." (with
> engineering judgment in italics).
>
> *html/physicalmod_mass_discuss1.html
>
> --is there a new image for this page? Note of "REPLACE THIS FIGURE WITH THE
> ONE SHOWING ACTUAL MASS MEASUREMENT WITH A SCALE."
>
> --is it possible to say a few words about the different parameters the
> students can choose from--I can see where students might miss the pull-down
> menu and subsequent information. The heading for the mass parameter draws
> more attention than the pull-down menu. Perhaps add a line at the bottom of
> the first explanation reminding students to choose another parameter from
> the pull-down menu at the top of the page.
>
> *html/physicalmod_spring_discuss1.html
>
> --please format the copyright information at the bottom of this page
>
> *html/mathmod_theory1.html
>
> --the first sentence: "The assumptions we have made in the Physical Model
> lead to some consequences that simplifies the Mathematical Model." should
> read: "The assumptions we have made in the Physical Model lead to some
> consequences that simplify the Mathematical Model."
>
> --the second thought bubble question has formatting problems in Netscape
> (but not in IE).
>
> --is it possible to break up this page and put some of the questions in the
> collaborate section?
>
> --again, the derivation of the equation shows up on a collaborate page. Is
> it necessary?
>
> *html/mathanalCFS_theory1.html
>
> --please format the copyright info at the bottom of this page
>
> --the phase plane box from this page--is there a plot to include? (again,
> there's a note indicating that there should be).
>
> *html/mathanal1CFS_sol.html
>
> --the first sentence: "To a solve second order homogeneous differential
> equation with constant coefficients," should read "To solve a second-order
> homogeneous differential equation with constant coefficients,"
>
> --in the middle of the page: "Then the general solution has one f the
> following forms:" should read "Then the general solution has one of the
> following forms:"
>
> --I like the "concepts" link active on the derivation pages so the student
> can get back to the concepts page easily, although I'm not sure why the
> derivations have "collaborate" as the functional heading.
>
> *html/mathanal1CFS_euler.html
>
> --please format the copyright information at the bottom of this page.
>
> *html/mathanal1CFS_trig.html
>
> --applet not working on this page--all I get is a blank box in both Netscape
> and IE.
>
> --please format the copyright info at the bottom of the page
>
> --is it possible to put some of the questions on a practice or collaborate
> page?
>
> *html/mathanalNS_theory1.html
>
> --The first paragraph has some minor grammatical errors: "A numerical
> solution is used to solve equations for dynamic systems. There are many ways
> to perform numerical analysis for dynamic systems. Below we have a block
> diagram sketched in Matlab/SIMULINK©. If you analyze the sketch carefully
> you can see that the dynamic equations are programmed in a visual format."
>
> Should read: "A numerical solution is used to solve equations for dynamic
> systems. There are many ways to perform numerical analyses for dynamic
> systems. Below we have a block diagram sketched in /SIMULINK©. If you
> analyze the sketch carefully, you can see that the dynamic equations are
> programmed in a visual format."
>
> --are students meant to link to Matlab/SIMULINK to do an exercise here? Or
> do the graph and explanation serve as examples only? perhaps a bit more
> explanation is needed to make that clear.
>
> *html/predbehav_exper1.html
>
> --I'm not sure why this page has a "discover" heading in the functional navigation
> bar.
>
> --great applet!
>
> -- Consider changing the first sentence from: "The predicted dynamic
> behavior of the spring-mass system results from an analytical solution or
> engineering simulation, so that is why it is called predicted." to: "The
> predicted dynamic behavior of the spring-mass system results from an
> analytical solution or engineering simulation." perhaps italicize the first
> instance of the word predicted (and delete the second clause) to emphasize
> that the essence of an analytical solution or engineering simulation is a
> prediction.
>
> *html/compare_case1_exper1.html
>
> --why is this under "discover" with a collaborate page? This would be
> clearer under a concepts page, with some of the "longer time" questions
> under collaborate, and the page currently under collaborate as a discover
> page.
>
> --before the second plot on the page: "Now we determine the predicted
> behavior by accounting for both the mass attached to the spring and the
> effective mass of the spring. The following picture compares plots o actual
> and predicted dynamical behaviors." Should read: "Now we determine the
> predicted behavior by accounting for both the mass attached to the spring
> and the effective mass of the spring. The following picture compares plots
> of actual and predicted dynamic behaviors."
>
> --before the third plot on the page: "The following figure compares plots of
> actual and predicted displacements, where the predictions use the dynamically
> calculated spring coefficient k along with the effective mass of the
> spring." should read: "The following figure compares plots of actual and
> predicted displacements, where the predictions use the dynamically calculate
> d spring coefficient k along with the effective mass of the spring."
>
>
> *html/compare1_collaborate.html
>
> --this might be a better "discover" page
>
> --are there applets to finish this page?
>
> *html/compare1_collaborate.html
>
> --from the middle of the page: "As we can see from the above figure, the
> actual and predicted dynamic behaviors match closely. Now let us look at for
> a later time window of same comparison." should read:
>
> "As we can see from the above figure, the actual and predicted dynamic
> behaviors match closely. Now let us look at a later time window of the same
> comparison."
>
> *Is it possible to make a mention of or highlight the differences between
> the damped and undamped versions as the students work through the damped
> track?
>
> *html/actualbehav_case1_exper2.html
>
> --again, I'm not sure I understand why this page was given a "discover"
> heading in the functional navigation bar.
>
> -- The first sentence: "The actual dynamic behavior of the undamped
> sprig mass system is presented below." should read: "The actual dynamic
> behavior of the damped spring-mass system is presented below." Assuming
> these parameters are for the damped version.
>
> *html/physicalmod_theory2.html
>
> --is it possible to make the labels for this schematic a bit bigger /
> clearer?
>
> --for clarity and emphasis on the idea of engineering judgment, consider
> rewording the passage: "The astuteness with which approximations are made at
> the outset of an investigation is the crux of engineering and applied
> mathematical analysis. The ability to make useful approximations that
> greatly simplify the system and still lead to a rapid, reasonably accurate
> prediction of its behavior is the hallmark of every successful engineer.
> This ability is engineering judgment. A list of assumptions regarding
> various aspects of the spring-mass system is given below."
>
> to: "Astute approximations made at the outset of an investigation create the
> crux of engineering and applied mathematical analysis. The hallmark of every
> successful engineer is good engineering judgment, the ability to make
> useful approximations that greatly simplify the system and still lead to a
> rapid, reasonably accurate prediction of its behavior. A list of assumptions
> regarding various aspects of the spring-mass system is given below."(with
> engineering judgment in italics)
>
> --The sentence under Damping: "Damping refers to energy-dissipation
> mechanisms, either intentional, such as dashpot, or parasitic, such as air
> friction, structural damping. In the sketch the presence of damping is
> indicated by a dashpot." should read: "Damping refers to energy-dissipation
> mechanisms, either intentional such as dashpot, or parasitic such as air
> friction or structural damping. In the sketch, the presence of damping is
> indicated by a dashpot."
>
> *html/physicalmod_mass_discuss2.html
>
> --again, is there meant to be a replacement schematic for the scale on this
> page?
>
> --also, is it possible to mention the other parameters the students should
> look at before moving on? (the reminder about the pull-down menu) Perhaps
> start with the dashpot parameter, since it is the newest information being
> introduced.
>
> *html/physicalmod_damping_discuss.html
>
> --please format the copyright information at the bottom of the page
>
> --typo in the first thought-bubble box: "How Can this graph be used to get
> the damping coefficient c?" should read: "How can this graph be used to get
> the damping coefficient c?" Other instances of can misspelled on this page
> (search and replace "can" with "can")
>
> --should the variables in the text be italicized?
>
> --are there supposed to be links associated with the "CLICK HEREs" on this
> page?
>
> *html/physicalmod_spring_discuss2.html
>
> --please format the copyright information at the bottom of this page.
>
> *html/mathmod_theory2.html
>
> --after the FBD for Newton's second law, "Now express Newton's law
> mathematically. You need to write F and a in terms of x, t, l, k, m, and any
> necessary constants, such as g." F and a should be italicized
>
> -- a bit further down the page, "How can a be rewritten? Choose one of the
> following." a should be italicized
>
> --the sentences: "To describe the problem completely it is necessary to
> specify the initial state of the system.
>
> How many initial conditions do you need?(What is the order of the
> differential equation?)
>
> What would be good choices for the initial conditions?
>
> Compare you answer with ours."
>
> should read: "To describe the problem completely, it is necessary to specify
> the initial state of the system.
>
> How many initial conditions do you need?(What is the order of the
> differential equation?)
>
> What would be good choices for the initial conditions?
>
> Compare your answer with ours."
>
> --is it possible to break some of the questions into the collaborate
> section?
>
> --The last sentence on the page is a fragment: "The differential equation
> along with the initial conditions for a mathematical model for the spring
> mass system." is this meant to say something more?
>
> *html/mathanal_theory2.html
>
> --broken link: ANALYTICAL SOLUTION
>
> *html/mathanalNS_theory2.html
>
> --is it possible to make this schematic more legible?
>
> --is it possible to include an explanation of the schematic? How is this
> schematic different from the undamped case of the SIMULINK model?
>
> *html/predbehav_exper2.html
>
> --is it possible to add a few words describing the applet? What should the
> students look for in this applet that is different from the similar applet
> in the undamped version?
>
> --again, I'm unsure as to why this has a "discover" heading in the
> functional navigation bar as it is a link on the side navigation bar (which indicates
> content).
>
> *html/compare_case1_exper2.html
>
> --this page has an old functional navigation bar (not the JavaScript script
> version)
>
> --the second sentence in the first paragraph: "The comparison of the actual
> dynamic behavior with the predictive dynamic behavior of the spring-mass
> system for the undamped case is presented here."
>
> should read: "The comparison of the actual dynamic behavior with the
> predictive dynamic behavior of the spring-mass system for the damped case is
> presented here."
>
> --is there a figure for this page?
>
> --are you missing data from this page? There are no equations for each case
> from the pull-down menu.
>
>
>
> Overall, I enjoyed this module as well. Great thought questions throughout
> the module! Fantastic schematics!
>
> Please contact me with any questions!
>
> Best regards,
> Ann
>
> Ann Navin
> Interface Designer
> Project Links: links.math.rpi.edu
> navina@rpi.edu
> 518.276.6136
>