Date: Fri, 17 Apr 1998 08:03:26 EDT From: Donald Rosenthal Subject: P12 - DR: Some Short Questions 1. In your paper you state: "Students carry out five or six different experiments in each of the fall and spring segments of the physical chemistry laboratory course. . . . The first semester (LabNet) site contains information about seven experiments." ^^^^^ In any given semester are some of these experiments not performed by any of the course students? 2. ". . a computer-based "experiment" was added to the course to teach students about error analysis and statistics . . ." Can you tell us more about this experiment? Is it available on the web? 3. "Much of the . . information is textual . . Most students still preferred to print out large sections of the site to keep a hard copy . . ." Wouldn't it be as convenient or more convenient to make these materials available to the students in printed form? The students could look the material over before coming to the recitation. 4. What experiments do the students perform in the second semester? 5. The theory involved in some of these experiments is somewhat advanced. Are these topics considered in the lecture course? I suppose some students perform the experiment before the topic is considered in the lecture course. Is this a problem? 6. I looked at the Gas Viscosity experiment. The nature of the pre-lab and final report is not clear to me. What sort of laboratory reports and pre-labs do you require? Do you require any sort of pre-lab (preliminary) report? What software do students use to analyze their data? [ Part 2: "Included Message" ] Date: Mon, 20 Apr 1998 07:29:00 EDT From: to2 Subject: Paper 12 - TOH: graphic formats I enjoyed reading your paper (#12). The idea of annotating digital photographs with clarifying markings is a fine one and falls into the "why-didn't-I-think-of-that" category. One question: In the section "Use of GIF's on the Site" you say: "Photographic images in the GIF (and sometimes JPEG) format are used...". How do you decide when to use GIF and when to use JPEG format? (I usually use JPEG for digital photographs of real objects and GIF for computer- generated drawings, charts, graphs, etc). Tom -------------------------------------------------- Tom O'Haver Professor of Analytical Chemistry Department of Chemistry and Biochemistry and Maryland Collaborative for Teacher Preparation The University of Maryland at College Park to2@umail.umd.edu http://www.wam.umd.edu/~toh [ Part 4: "Included Message" ] Date: Mon, 20 Apr 1998 09:51:40 -0400 From: George Long Subject: Time required to create this material Gabriella, My question concerns the time required to produce such material. I gather a significant amount of time was invested in creating the website, and as you move to the more interactive website, there will be a huge amount of time spent for creating the material. At some point, won't the time/student ratio will make it unreasonable, if not impossible to do this kind of thing. In particular, for a class like P-Chem that traditionally has lower enrollment. Do you forsee any benefits that make the time investment worthwhile (beyond what you gain from learning how to create a useful site) **************************************************************************** Dr. George R. Long grlong@grove.iup.edu http://www.iup.edu/~grlong/ Department of Chemistry Indiana University of PA Indiana PA, 15705 **************************************************************************** [ Part 6: "Included Message" ] Date: Mon, 20 Apr 1998 11:51:43 -0600 From: Gabriela Weaver Subject: Re: P12 - DR: Some Short Questions > 1. In your paper you state: > "Students carry out five or six different experiments in each of > the fall > and spring segments of the physical chemistry laboratory > course. . . . The first semester (LabNet) site contains > information about seven experiments." > ^^^^^ > > In any given semester are some of these experiments not performed > by any of the course students? > Although the "Speed of Sound" and "Speed of Light" experiments are presented as two different experiments on the site, they were carried out by students in the same lab period and turned in as one experimental write-up. They are both short experiments, and my goal in having students do them was to introduce them to the lasers and elctronics they would be using the subsequent semester in more advanced experiments. In general, all students do all of the experiments assigned for a given semester. As I mentioned, though, they don't do them in the same order. The selection of experiments that students do during the fall semester has changed very slightly from year to year, with maybe one experiment being changed. > 2. ". . a computer-based "experiment" was added to the course to > teach students about error analysis and statistics . . ." > > Can you tell us more about this experiment? Is it available on the > web? It isn't currently available on the Web but, since I wrote it, it would be very easy for me to convert it to a Web format. I'd be happy to do so if there is interest. I put the word "experiment" in quotes because it is really more of an exercise intended to introduce students to some of the concepts of statistics and error analysis. It goes over precision/accuracy, sources of error (random/ systematic), mean, median, probability, the gaussian distribution, normalized distributions, the standard deviation, confidence intervals, using the total differential to calculate propagated error, least squares fitting and the errors associated with the slope and interecept, and how to report relative errors. > > 3. "Much of the . . information is textual . . > Most students still preferred to print out large sections of the > site to keep a hard copy . . ." > > Wouldn't it be as convenient or more convenient to make > these materials available to the students in printed form? > The students could look the material over before coming to > the recitation. > The course was run a little differently this (spring) semester. Students did, in fact, look at the material on the Web before they came to recitation. In previous years we did hand out the material in printed form. However, printed form won't let me take advantage of some of the graphical capabilities of the Web which are specifically what I'm trying to use to enhance the students' recitation experience. Also, students often read what they need to on-line, and print out those parts they want to have access to repeatedly, like the procedures. I was recently able to assess the LabNet site by survey and by interview with the students. (These results are recent enough that I was not able to include them in the paper on ChemConf). Among the things I discovered is that students very much liked having the Web version available more than they liked having handouts of the same material. They felt that the hyperlinked environment of the Web made it easier to get to the information they wanted and they felt that the graphical additions were helpful to their understanding of the materials and procedures. > 4. What experiments do the students perform in the second semester? The second semester experiments have been changing pretty extensively since I took over the lab because I have slowly been acquiring lasers and integrating them into the curriculum. This year, students did the rotational-vibrational spectrum of HCl/DCl (a classic), the UV and visible absorption spectra of iodine and bromine, the absorption spectra and molecular modeling of cyanine dyes, fluorescent lifetimes and quencher effects carried out with our pulsed laser, and a molecular modeling experiment to determine Raman-active and IR- active vibrational modes. The last two experiments were added this year. The last experiment was carried out completely on our SGI workstation using Spartan; however, I intend for it to include a hands-on Raman and IR component next year, once we take delivery of our new CW laser. > > 5. The theory involved in some of these experiments is somewhat > advanced. > Are these topics considered in the lecture course? > > I suppose some students perform the experiment before the topic > is considered in the lecture course. Is this a problem? I do make an effort to tie the lab concepts to the lecture concepts, and vice versa. However, the specific lab topics aren't always covered in depth in the lecture course. In those cases the recitation, and LabNet, will need to provide students with the information they need. You have hit on an important issue, though. Some students do indeed carry out the experiment before the material is covered. LabNet was created to try to alleviate the problem of presenting the background material necessary for each student since we are parallel processing the experiments in the labs. But, there is the added issue that some students might carry out an experiment on a topic, such as ro-vibrational spectra, before we get to that in lecture. The experiments have been organized, relative to the order of lecture topics, to minimize the chance of this occurring. When it does happen, I personally don't think of it as a problem. Having students work through concepts experimentally before they delve into the theory might actually strengthen their understanding of those concepts in the long run. I don't think that laboratory necessarily needs to follow lecture at all times, but that sometimes the reverse might be a better approach. I talk to my students about this and, so far, they have no problems with that approach in this level of chemistry class. (On the other hand, I have seen students complain about it bitterly in courses such as general chemistry.) > 6. I looked at the Gas Viscosity experiment. The nature of the > pre-lab and final report is not clear to me. > > What sort of laboratory reports and pre-labs do you require? > > Do you require any sort of pre-lab (preliminary) report? > > What software do students use to analyze their data? > First, let me address your comment about the gas viscosity experiment. The gas viscosity experiment is perhaps the one with the most difficult theory and procedure of all the experiments that our students carry out. I'm not particularly happy with the current state of the LabNet page on this experiment and it will be among the revisions that will go on this summer. However, this experiment has always required me to spend a lot of individual time with students going over particular details with them. Having the LabNet site allowed students to get through all the material they did understand and then come to me for help with the sections that were not clear to them. They felt this was helpful because different students had problems understanding different sections of the lab, and I could focus on getting them over their specific hurdles. Now, regarding prelabs and reports: I require a relatively minimal pre-lab from students. It consists of a summary in their own words of the purpose and theory of the experiment they will perform, a listing of the equations they will need in analyzing their data, and tables prepared ahead of time that they will use when taking their data. I have found that students cannot provide these things and cannot do them well unless they have carefully read the material for the experiment and *understand* what they will be doing. The data tables are particularly telling with respect to their level of undertanding of the procedures and instruments they will be using. I am hoping to add some pre-lab questions on LabNet this summer. Students' answers to these questions will be sent to me electronically when they actually do the LabNet prelab. The remainder of the pre-lab is done in the students' notebooks. I check these notebook pre-labs when students come into lab each week and the prelab is part of their grade. I go over things with them that I feel they might not understand before they start the lab. As for the laboratory report, each experiment requires different types of anlyses and explanation. Most involve fitting and reducing data in a number of ways, comparing to literature values, and discussing the meaning of their results as well as the sources of error. Students often use Excel for their anlyses, some of them have started using MathCad since I introduced it into the course this year, and a few students have used other spreadsheet programs. Gabriela C. Weaver Assistant Professor University of Colorado at Denver Chemistry Department Campus Box 194 P. O. Box 173364 Denver, CO 80217-3364 Phone: (303) 556-3201 Fax: (303) 556-4776 [ Part 7: "Included Message" ] Date: Mon, 20 Apr 1998 12:01:09 -0600 From: Gabriela Weaver Subject: Re: Paper 12 - TOH: graphic formats > I enjoyed reading your paper (#12). The idea of annotating > digital photographs with clarifying markings is a fine one and falls > into the "why-didn't-I-think-of-that" category. > > One question: In the section "Use of GIF's on the Site" you > say: "Photographic images in the GIF (and sometimes JPEG) format are > used...". How do you decide when to use GIF and when to use JPEG > format? (I usually use JPEG for digital photographs of real objects > and GIF for computer- generated drawings, charts, graphs, etc). > > Tom > -------------------------------------------------- > Tom O'Haver > Professor of Analytical Chemistry > Department of Chemistry and Biochemistry > and Maryland Collaborative for Teacher Preparation The University > of Maryland at College Park > to2@umail.umd.edu > http://www.wam.umd.edu/~toh > > Tom, many of my photos are in gif format for the simple reason that, at the time I converted them into digital images, I didn't have software that would save them in another format. Now I choose whichever format gives me the most compressed image with reasonable quality - I've found this is usually JPEG for photographs. Gabriela C. Weaver Assistant Professor University of Colorado at Denver Chemistry Department Campus Box 194 P. O. Box 173364 Denver, CO 80217-3364 Phone: (303) 556-3201 Fax: (303) 556-4776 [ Part 8: "Included Message" ] Date: Mon, 20 Apr 1998 12:10:32 -0600 From: Gabriela Weaver Subject: Re: Time required to create this material > Gabriella, > > My question concerns the time required to produce such material. I > gather a significant amount of time was invested in creating the > website, and as you move to the more interactive website, there will be > a huge amount of time spent for creating the material. At some > point, won't the time/student ratio will make it unreasonable, if > not impossible to do this kind of thing. In particular, for a class > like P-Chem that traditionally has lower enrollment. Do you forsee > any benefits that make the time investment worthwhile (beyond what > you gain from learning how to create a useful site) > > ************************************************************************** > ** > Dr. George R. Long grlong@grove.iup.edu http://www.iup.edu/~ > grlong/ Department of Chemistry > Indiana University of PA > Indiana PA, 15705 > > ************************************************************************** I was able to create this site because I received an internal (University of Colorado) grant to do so. That grant money was spent primarily on paying salaries for the students who actually did the programming for the site. My time was usually spent telling them what should be on the site and then editing the site. I also did most of the graphics and videos, and students did the animations. If I did not have the grant to make the LabNet site I would either have had to do the programming myself or find another way to compensate students to do the work. In the latter case, they might be able to do it as a for-credit independent study project or as part of some work-study. In the former case, you are absolutely right that I could not actually find that much time in the day to do it myself. However, because our course is not expected to change too dramatically from year to year, the effort is essentially all on the front-end. Once the site is up and running, it should take minimal work and minimal revisions to keep it updated. I expect that it will take no more time to keep the site up and running than it used to take me to prepare a lecture for the recitation. Gabriela C. Weaver Assistant Professor University of Colorado at Denver Chemistry Department Campus Box 194 P. O. Box 173364 Denver, CO 80217-3364 Phone: (303) 556-3201 Fax: (303) 556-4776 [ Part 9: "Included Message" ] Date: Mon, 20 Apr 1998 14:50:32 -0400 From: Leon Combs Chemistry Subject: Phys Chem labs I enjoyed reading the paper by Dr. Weaver and appreciated it for I have struggled with the same problem for some years. The problem being that we have seven or so experiments going on simultaneously. Many years ago I and a graduate student put together a set of audio-video slides (remember the player which allowed keying of slide presentations with an audio tape?) for the students to watch/listen before the lab. Then I moved to my present location where most students work off campus (no dorms, 13,000 students) and I and some undergraduate students put together a set of video tapes demonstrating each experiment with especial attention to the more difficult aspects of the experiments. The students had to go to the library to view the tapes. Then I added a web page with some pre-lab questions which they would have to answer and send to me before the lab. Now I am adding streaming video to the web page so that they can watch at home and then answer the pre-lab questions and send them to me. They prepare their lab reports using MathCad. I am reasonably pleased with how my approach has evolved over the years, and I am pleased to see someone else doing something very similar. My streaming video site will not be ready until this summer, but if you send me an e-mail address I will be glad to send you the address later. I don't want to take anything away from Dr. Weaver's paper -- excellent work. Leon Leon L. Combs, Ph.D. Tel: 770-423-6159 Professor and Chair FAX: 770-423-6744 Department of Chemistry lcombs@ksumail.kennesaw.edu Kennesaw State University http://science.kennesaw.edu/~lcombs 1000 Chastain Road CARPE DIEM ---- CORUM DEO Kennesaw, GA 30144 [ Part 10: "Included Message" ] Date: Mon, 20 Apr 1998 16:41:00 -0400 From: Jimmy Reeves Subject: DR: Some Short Questions [The following text is in the "iso-8859-1" character set] [Your display is set for the "ISO-LATIN" character set] [Some characters may be displayed incorrectly] Gabriela et al You write: It isn't currently available on the Web but, since I wrote it, it would be very easy for me to convert it to a Web format. I'd be happy to do so if there is interest. I put the word "experiment" in quotes because it is really more of an exercise intended to introduce students to some of the concepts of statistics and error analysis. It goes over precision/accuracy, sources of error (random/ systematic), mean, median, probability, the gaussian distribution, normalized distributions, the standard deviation, confidence intervals, using the total differential to calculate propagated error, least squares fitting and the errors associated with the slope and interecept, and how to report relative errors. My response: This sounds like a really good idea to me, especially if it includes "real data" from a "typical experiment" that the students can chew on. My experience (possibly dated, but I doubt it) is that error analysis in general and the dreaded propagation of errors in particular are extremely tough things for students to learn to do properly, and an exercise like this would benefit not only P Chem Lab, but Analytical Courses as well. You say: You have hit on an important issue, though. Some students do indeed carry out the experiment before the material is covered. LabNet was created to try to alleviate the problem of presenting the background material necessary for each student since we are parallel processing the experiments in the labs. But, there is the added issue that some students might carry out an experiment on a topic, such as ro-vibrational spectra, before we get to that in lecture. The experiments have been organized, relative to the order of lecture topics, to minimize the chance of this occurring. When it does happen, I personally don't think of it as a problem. Having students work through concepts experimentally before they delve into the theory might actually strengthen their understanding of those concepts in the long run. I don't think that laboratory necessarily needs to follow lecture at all times, but that sometimes the reverse might be a better approach. I talk to my students about this and, so far, they have no problems with that approach in this level of chemistry class. (On the other hand, I have seen students complain about it bitterly in courses such as general chemistry.) My response: You are exactly correct about this being an important issue; one can even envision a P Chem experiment intentionally designed to teach the concept by discovery, so that follow-up in lecture builds on the surprises encountered in the lab. One experiment that lends itself to this is the freezing point of a mixed solid (naphthalene and biphenyl is the experiment I used to do) in which you give them the melting points of the two pure solids and ask them to predict the melting point of a mixture. When they pick the average between the two, and measure a very different result, all kinds of valuable discussions become possible. Judiciously applied, discovery based labs of this type might help connect the results of lecture and lab for students. ************************************************ Dr. Jimmy Reeves Associate Professor of Chemistry University of North Carolina at Wilmington 601 S. College Rd. Wilmington, NC 28403 Office: 910-962-3456 Fax: 910-962-3013 WWW: http://www.uncwil.edu/people/reeves/ ******************************************************** [ Part 11: "Included Message" ] [ Part 12: "Included Message" ] Date: Mon, 20 Apr 1998 15:19:32 -0600 From: Gabriela Weaver Subject: Re: DR: Some Short Questions > > My response: > > This sounds like a really good idea to me, especially if it includes > "real data" from a "typical experiment" that the students can chew on. > My experience (possibly dated, but I doubt it) is that error analysis > in general and the dreaded propagation of errors in particular > are extremely tough things for students to learn to do properly, and > an exercise like this would benefit not only P Chem Lab, but > Analytical Courses as well. > > > ************************************************ > Dr. Jimmy Reeves > Associate Professor of Chemistry > University of North Carolina at Wilmington > 601 S. College Rd. > Wilmington, NC 28403 > > Office: 910-962-3456 > Fax: 910-962-3013 > WWW: http://www.uncwil.edu/people/reeves/ > ******************************************************** > There is a problem included in the exercise which uses "real data," i.e. data that I specifically designed to be non-ideal. As part of the analysis, students need to identify the outliers by examining the residuals and justifying their selection of which points to throw out. Gabriela C. Weaver Assistant Professor University of Colorado at Denver Chemistry Department Campus Box 194 P. O. Box 173364 Denver, CO 80217-3364 Phone: (303) 556-3201 Fax: (303) 556-4776