Wednesday, May 27, 2009
Poster Session #2 Wednesday 6:30 pm
The second poster session was tonight consisting mainly of Mark and Nick's recitation sections as well as groups from Dr. Dutta and Dr. Cuthberts class. Again, things went very well and I really appreciate the enthusiasm shown by all the groups. Keep up the great work!
Lecture #25, Wednesday, May 27th
Today I started lecture discussing the relationship between the cell potential and the Gibbs free energy of a reaction, then discussed the influence concentration has on the cell potential and we derived the Nernst equation. I went over several examples of calculating the cell potential under nonstandard conditions.
On Friday we will discuss electrolysis and start talking about batteries, fuel cells, and photovoltaic cells.
Be sure to be keeping up with the electrochemistry homework sets posted on carmen, as next week's quiz will be primarily electrochemistry.
On Friday we will discuss electrolysis and start talking about batteries, fuel cells, and photovoltaic cells.
Be sure to be keeping up with the electrochemistry homework sets posted on carmen, as next week's quiz will be primarily electrochemistry.
Poster Session #1: Tuesday May 26th
The first poster session was held in the Physics Research Building at 6:30 pm and it went very well. I am glad to see the enthusiasm and sense of pride as you present your research projects. It is a true privilege to be able to have the opportunity to participate in a poster session like this and I am delighted to be part of the program.
The National Science Foundation also had representatives in attendance and I could definitely tell they were impressed by the presentations. Great job for the first night!
The National Science Foundation also had representatives in attendance and I could definitely tell they were impressed by the presentations. Great job for the first night!
Lectures #23 and #24 Wed, May 20th and Fri, May 22nd
May 20th is my sister's birthday. So a special shout out to my sister Anita and a Happy 26th Birthday :) I wish I lived closer to home so I could get to see you more.
I started the introduction of electrochemistry by outlining the two processes we will be using in Exp #28 and Exp #29. They are the generation of an electric current from a chemical reaction and the use of an electric current to produce a chemical change. The first is referred to as a galvanic or voltaic process and occurs spontaneously. The second is an electrolytic process and is not spontaneous. We will investigate voltaic cells in Exp #28 and electrolytic cells in Exp #29.
We then discussed cell potential and talked about how everything is standardized to the hydrogen electrode. We talked about oxidation/reduction (redox) reactions and how to describe a galvanic cell. We went through several examples of these cells and be sure you know how to analyze them as they will come up in the final as well as Exp #28 and #29.
I started the introduction of electrochemistry by outlining the two processes we will be using in Exp #28 and Exp #29. They are the generation of an electric current from a chemical reaction and the use of an electric current to produce a chemical change. The first is referred to as a galvanic or voltaic process and occurs spontaneously. The second is an electrolytic process and is not spontaneous. We will investigate voltaic cells in Exp #28 and electrolytic cells in Exp #29.
We then discussed cell potential and talked about how everything is standardized to the hydrogen electrode. We talked about oxidation/reduction (redox) reactions and how to describe a galvanic cell. We went through several examples of these cells and be sure you know how to analyze them as they will come up in the final as well as Exp #28 and #29.
Lecture #22 Monday, May 18th
Day of Midterm Exam #2
Today I introduced the very last unit of our class, which will look into alternate forms of energy. To start the introduction, I played a clip (the 23:25 mark) form a speech given by President Obama where he outlined the need for coming up with renewable energy.
I also highlighted the key points from a lecture given by Dr. Daniel Nocera, The Henry Dreyfus Professor of Energy and Professor of Chemistry, at MIT. Dr. Nocera's research has a large focus on chemical energy conversion, which is based on the foundations of electrochemistry, which will be the next main topic discussed in class.
Nocera's lecture is posted on carmen and it describes the energy crisis we are currently facing, and gives an idea of how much time we have left using our current fuels. The key I wanted to emphasize from his talk is that there is so much potential energy stored in a chemical bond and if we can somehow figure out a way to utilize it, we will solve the worlds energy crisis.
This helped set the stage for the importance of the upcoming electrochemistry unit, as electrochemistry is the study of the conversion between chemical and electrical energy.
Today I introduced the very last unit of our class, which will look into alternate forms of energy. To start the introduction, I played a clip (the 23:25 mark) form a speech given by President Obama where he outlined the need for coming up with renewable energy.
I also highlighted the key points from a lecture given by Dr. Daniel Nocera, The Henry Dreyfus Professor of Energy and Professor of Chemistry, at MIT. Dr. Nocera's research has a large focus on chemical energy conversion, which is based on the foundations of electrochemistry, which will be the next main topic discussed in class.
Nocera's lecture is posted on carmen and it describes the energy crisis we are currently facing, and gives an idea of how much time we have left using our current fuels. The key I wanted to emphasize from his talk is that there is so much potential energy stored in a chemical bond and if we can somehow figure out a way to utilize it, we will solve the worlds energy crisis.
This helped set the stage for the importance of the upcoming electrochemistry unit, as electrochemistry is the study of the conversion between chemical and electrical energy.
Lecture #20 and #21 Wed May 13th and Fri May 15th
The three laws of Thermodynamics were covered and entropy and spontaneous reactions were introduced. We talked about the entropy of the universe and the entropy of a system.
Gibbs Free Energy was introduced and we discussed the relationship between free energy, entropy, and enthalpy. I touched on Experiment #32 (which we will not perform in this class) and how free energy is related to the equilibrium constant, k. This value can be experimentally determined via an acid/base titration.
Lastly, the chelate effect was analyzed as the magnitude of the formation constant can be analyzed by looking into the entropy of the reaction occurring.
Gibbs Free Energy was introduced and we discussed the relationship between free energy, entropy, and enthalpy. I touched on Experiment #32 (which we will not perform in this class) and how free energy is related to the equilibrium constant, k. This value can be experimentally determined via an acid/base titration.
Lastly, the chelate effect was analyzed as the magnitude of the formation constant can be analyzed by looking into the entropy of the reaction occurring.
Monday, May 11, 2009
Exam #2 Review Session
The review session for the second exam will take place from 5:00 - 6:48 pm on Friday, May 15th.
Also, in addition to the regularly scheduled office hours I will be holding extra office hours on Tues and Wed evening from 7 - 9 pm.
This weeks quiz will be a take home quiz distributed as soon as we decide on the content of the final report. It will most likely consist of the questions to be addressed from phase 1 of the final REEL project.
The exam will be made up of questions pulled from the content of REEL labs 1, 2, 3, and 4. I am currently working on making up a summary of the content from REEL labs 1 and 4 to give you a comprehensive review sheet for all the REEL labs.
Also, in addition to the regularly scheduled office hours I will be holding extra office hours on Tues and Wed evening from 7 - 9 pm.
This weeks quiz will be a take home quiz distributed as soon as we decide on the content of the final report. It will most likely consist of the questions to be addressed from phase 1 of the final REEL project.
The exam will be made up of questions pulled from the content of REEL labs 1, 2, 3, and 4. I am currently working on making up a summary of the content from REEL labs 1 and 4 to give you a comprehensive review sheet for all the REEL labs.
Lecture #19, Monday, May 11th
Today we continued with Chapter 19, which is Chemical Thermodynamics. I highlighted the key points from sections 19.1 through 19.4 of the text book. Be sure to read those sections. If you want to get ahead of the game for Wednesday's lecture read sections 19.5 and 19.6.
Based on several requests from students, I posted a few things on carmen to guide you in writing your final REEL research paper. The first document is an article from an old edition of the Journal of Education giving you a good idea of how to write with a scientific style. The second is the journal article I highlighted in class last week. The third is the final REEL report submitted by Derek Smith, who was a student in the class last year. His report was the best report submitted by the 300 students and is an excellent guide for how the paper should be put together.
Based on several requests from students, I posted a few things on carmen to guide you in writing your final REEL research paper. The first document is an article from an old edition of the Journal of Education giving you a good idea of how to write with a scientific style. The second is the journal article I highlighted in class last week. The third is the final REEL report submitted by Derek Smith, who was a student in the class last year. His report was the best report submitted by the 300 students and is an excellent guide for how the paper should be put together.
Friday, May 8, 2009
Lecture #18, Friday, May 8th
Today I outlined the overview of the REEL research projects. There are two main themes present in the project. #1 In REEL 4 we saw that cations with an ns2 cation or a Ag+ can effectively reduce the band gap. We want to investigate what will happen when we form a solid solution between end members containing these cations. More importantly, we want to see how the band gap changes as we change the4 composition of x. Does the band gap consistently change as we go from x = 0.1 to x = 0.9, does it lie very close to end member A, or does it lie close to end member B? There might be rare cases where the band gap of a solid solution falls outside the band gap of the end members. This could be a consequence of forming a two phase mixture or a compound with impurities, or it could be because there is a rare case. What you will have to do is prove to us if you have a two phase mixture or a solid solution based upon your XRD pattern.
We also want to look at various effects of putting a transition metal with valence d electrons in a solid solution. Do the absorption bands resulting from the d to d transitions stay at the exact same absorbance, or do they move to the left or to the right?
Next, we started with the Thermodynamics unit and will continue with that later next week. I hope everyone has a great mother's day weekend. Don't forget to tell your mom how much you care about her. You never know when your last opportunity to do that will be.
See you in class on Monday, Dr. Fus
We also want to look at various effects of putting a transition metal with valence d electrons in a solid solution. Do the absorption bands resulting from the d to d transitions stay at the exact same absorbance, or do they move to the left or to the right?
Next, we started with the Thermodynamics unit and will continue with that later next week. I hope everyone has a great mother's day weekend. Don't forget to tell your mom how much you care about her. You never know when your last opportunity to do that will be.
See you in class on Monday, Dr. Fus
Wednesday, May 6, 2009
Relay For Life
Relay for Life is taking place at Fred Beekman Park (West Campus) from Sat at noon until Sun at noon. Check out the following web page for details
http://www.chemistry.ohio-state.edu/~mstoltzf/HOPE/
I still have a few T-shirts available and I encourage everyone who bought a shirt to please wear them to class on Friday. Hope to see everyone out there, Dr. Fus
http://www.chemistry.ohio-state.edu/~mstoltzf/HOPE/
I still have a few T-shirts available and I encourage everyone who bought a shirt to please wear them to class on Friday. Hope to see everyone out there, Dr. Fus
Indian Student Association Elections
Indian Students Association (ISA) have elections coming up.
• The voting goes on for 3 days, starting Friday(May 8th) to Sunday(May 10th)
• Every Indian is allowed to vote from their osu/buckeyemail id once.
Use your lastname.#@osu.edu/ lastname.#@buckeyemail.osu.edu id to mail your votes
To: isabuckeyes@gmail.com
Subject Line: ISA Elections
In the body write your votes,
President: Romel Somavat
Vice President: Sonya Jindal
Treasurer: Aditya Uppukonduru
Thank you for your support!
• The voting goes on for 3 days, starting Friday(May 8th) to Sunday(May 10th)
• Every Indian is allowed to vote from their osu/buckeyemail id once.
Use your lastname.#@osu.edu/ lastname.#@buckeyemail.osu.edu id to mail your votes
To: isabuckeyes@gmail.com
Subject Line: ISA Elections
In the body write your votes,
President: Romel Somavat
Vice President: Sonya Jindal
Treasurer: Aditya Uppukonduru
Thank you for your support!
Lecture #17, Wednesday, May 6th
After blasting Lil' Wayne and the Game's My Life I started lecture on solid state synthesis. I reiterated why we have to grind samples for extended periods of time and emphasized the fact that we have to PROVE the identity of the synthesized product. This is done by properly interpreting an XRD pattern.
We went through various scenarios of the attempt to synthesize BiVO4 by reacting Bi2O3 with V2O5. At room temperature only the starting materials exist and we see two distinct structures in the XRD pattern. As we gradually heat the reactants we see the peaks originating from the starting materials begin to get weaker and peaks from BiVO4 begin to form. As heating progresses, the BiVO4becomes a pure homogeneous phase. Something happens though when we heat to higher temperatures. The XRD pattern reveals there are additional peaks, which tell us something is going on. What is happening is when the synthetic temperature gets over 475 degrees the BiVO4 converts over to another structure type. Using X-ray diffraction we can monitor the temperature this transition occurs.
I also discussed the capabilities and limitations X-ray diffraction and UV-Vis spectroscopy. An X-ray diffractometer can tell us which crystal structure(s) is/are present, but it cannot tell us the color of a compound. A UV-Vis spectrometer can tell us which excitations are responsible for the color of a compound, but we cannot verify a structure using UV-Vis. When both of these instrumentation are combined together they can be extremely powerful in determining structure-property relationships, or how changing a crystal structure can have an impact on the color of a compound.
We went over several examples from class and showed how combining XRD and UV-Vis can give us very valuable information. I then discusses how the valence electron count on the cation has an impact on the band gap of a solid. On Friday we will discuss various ways to manipulate the band gap of a solid and go into the details how an extended solid differs from a discrete molecule. We will also discuss the impact of choosing a transition metal for the cation, and how its d orbitals will affect the color of a compound. I will see everyone in class on Friday, Dr. Fus
We went through various scenarios of the attempt to synthesize BiVO4 by reacting Bi2O3 with V2O5. At room temperature only the starting materials exist and we see two distinct structures in the XRD pattern. As we gradually heat the reactants we see the peaks originating from the starting materials begin to get weaker and peaks from BiVO4 begin to form. As heating progresses, the BiVO4becomes a pure homogeneous phase. Something happens though when we heat to higher temperatures. The XRD pattern reveals there are additional peaks, which tell us something is going on. What is happening is when the synthetic temperature gets over 475 degrees the BiVO4 converts over to another structure type. Using X-ray diffraction we can monitor the temperature this transition occurs.
I also discussed the capabilities and limitations X-ray diffraction and UV-Vis spectroscopy. An X-ray diffractometer can tell us which crystal structure(s) is/are present, but it cannot tell us the color of a compound. A UV-Vis spectrometer can tell us which excitations are responsible for the color of a compound, but we cannot verify a structure using UV-Vis. When both of these instrumentation are combined together they can be extremely powerful in determining structure-property relationships, or how changing a crystal structure can have an impact on the color of a compound.
We went over several examples from class and showed how combining XRD and UV-Vis can give us very valuable information. I then discusses how the valence electron count on the cation has an impact on the band gap of a solid. On Friday we will discuss various ways to manipulate the band gap of a solid and go into the details how an extended solid differs from a discrete molecule. We will also discuss the impact of choosing a transition metal for the cation, and how its d orbitals will affect the color of a compound. I will see everyone in class on Friday, Dr. Fus
Monday, May 4, 2009
Lecture #16, Monday, May 4th
I started lecture today by analyzing what would result if we attempted to make a solid solution between NaCl and KCl. Since Na+ and K+ are fairly close in ionic radii a complete solid solution can exist, which has the rock salt structure. The evidence supporting this claim is proper interpretation of the X-ray diffraction pattern.
In your research project we don't know the answers to the questions we are trying to ask. We have to PROVE our conclusions are true. In order to do this you need to use the advanced instrumentation (XRD and UV-Vis) and be able to interpret what these machines are telling us. The main thing we will be analyzing in REEL lab #4 is if a solid solution formed or you have a 2 Phase mixture and what electronic excitations are giving rise to the color in your solid solutions.
Now going back to the lecture topics, we next looked at the solid solution between LiCl and RbCl, and found that the Li0.5Rb0.5Cl was not a solid solution at all, rather a two phase mixture. This was determined from the direct interpretation of the XRD pattern. There were peaks present in the pattern from both the structures of LiCl and RbCl and from that we determined two phases were present.
At this point in lecture our special guest, President E. Gordon Gee arrived to talk to you about the importance of research in our University community and in today's society. As President Gee looked up and pointed at the periodic table his first response was "Now that's what made me a lawyer. Organic Chemistry."
A few comments/facts President Gee said that stuck out to me...
He was able to rattle off the exact number of students enrolled at Ohio State and he listed us as the #9 school in terms of the amount of money earned from research grants. This tells me that everyone has the opportunity to do research in some capacity.
He also touched on how many options students have here at Ohio State. Not only from majors to choose from, but there are extraordinary faculty members here that you have the opportunity to learn from and collaborate with. Take advantage of this.
President Gee also pointed out how different the academic setting is from when he was in school. Years ago students came to college, had a big party, joined a fraternity or sorority, sang kum ba ya, and in four years they had a job. Today's academic climate has changed and more and more focus is on research.
He also shared with us a conversation he had with the Ambassador for education from China. One of the questions in his discussion was "What are you doing to make your students more creative?" It is creativity and the ability to think critically that will separate you from the rest of your peers. I hope the REEL project really emphasizes these points and challenges you to creatively think for yourself. It is a different train of thought than following a 30 step process and getting an answer that you know should be correct. It is a research train of thought and rather than asking "Is this right?" you are now being able to prove to me and your TA that you arrived at a correct conclusion.
I hope you could take something away from what President Gee has to say. We are very privileged to have him as our President and it is great to know that he cares for the students enough to come in and talk and try to encourage and motivate and inspire us to get involved with research. I would encourage all of you to check out the web page of the Undergraduate Research Office (URO) and it is my goal to get all of you matched up with a professor you could do research with in your major field. This is an excellent place to start in terms of looking for research here at the University.
On day #1 of the REEL lab this week the main objective is to collect an XRD and diffuse reflectance spectra of all your compounds. On day #2 of this week we will analyze them and try to determine the reason why the solid solutions exist the way they do and to figure out the reason for the variation in color across a solid solution series.
After tomorrow's lab I will update the blog with the results obtained from the XRD and UV-Vis and Wednesday's lecture will go into detail with specific examples collected during Mon and Tues.
There is also a quiz on Wed/Thurs of this week. Be sure to look over the questions I posted on carmen for REEL labs #2 and #3. They will make up a large portion of the quiz.
I hope everyone enjoyed President Gee's comments today. See you in class on Wed, Dr. Fus
In your research project we don't know the answers to the questions we are trying to ask. We have to PROVE our conclusions are true. In order to do this you need to use the advanced instrumentation (XRD and UV-Vis) and be able to interpret what these machines are telling us. The main thing we will be analyzing in REEL lab #4 is if a solid solution formed or you have a 2 Phase mixture and what electronic excitations are giving rise to the color in your solid solutions.
Now going back to the lecture topics, we next looked at the solid solution between LiCl and RbCl, and found that the Li0.5Rb0.5Cl was not a solid solution at all, rather a two phase mixture. This was determined from the direct interpretation of the XRD pattern. There were peaks present in the pattern from both the structures of LiCl and RbCl and from that we determined two phases were present.
At this point in lecture our special guest, President E. Gordon Gee arrived to talk to you about the importance of research in our University community and in today's society. As President Gee looked up and pointed at the periodic table his first response was "Now that's what made me a lawyer. Organic Chemistry."
A few comments/facts President Gee said that stuck out to me...
He was able to rattle off the exact number of students enrolled at Ohio State and he listed us as the #9 school in terms of the amount of money earned from research grants. This tells me that everyone has the opportunity to do research in some capacity.
He also touched on how many options students have here at Ohio State. Not only from majors to choose from, but there are extraordinary faculty members here that you have the opportunity to learn from and collaborate with. Take advantage of this.
President Gee also pointed out how different the academic setting is from when he was in school. Years ago students came to college, had a big party, joined a fraternity or sorority, sang kum ba ya, and in four years they had a job. Today's academic climate has changed and more and more focus is on research.
He also shared with us a conversation he had with the Ambassador for education from China. One of the questions in his discussion was "What are you doing to make your students more creative?" It is creativity and the ability to think critically that will separate you from the rest of your peers. I hope the REEL project really emphasizes these points and challenges you to creatively think for yourself. It is a different train of thought than following a 30 step process and getting an answer that you know should be correct. It is a research train of thought and rather than asking "Is this right?" you are now being able to prove to me and your TA that you arrived at a correct conclusion.
I hope you could take something away from what President Gee has to say. We are very privileged to have him as our President and it is great to know that he cares for the students enough to come in and talk and try to encourage and motivate and inspire us to get involved with research. I would encourage all of you to check out the web page of the Undergraduate Research Office (URO) and it is my goal to get all of you matched up with a professor you could do research with in your major field. This is an excellent place to start in terms of looking for research here at the University.
On day #1 of the REEL lab this week the main objective is to collect an XRD and diffuse reflectance spectra of all your compounds. On day #2 of this week we will analyze them and try to determine the reason why the solid solutions exist the way they do and to figure out the reason for the variation in color across a solid solution series.
After tomorrow's lab I will update the blog with the results obtained from the XRD and UV-Vis and Wednesday's lecture will go into detail with specific examples collected during Mon and Tues.
There is also a quiz on Wed/Thurs of this week. Be sure to look over the questions I posted on carmen for REEL labs #2 and #3. They will make up a large portion of the quiz.
I hope everyone enjoyed President Gee's comments today. See you in class on Wed, Dr. Fus
Lecture #15, Friday, May 1st
Can you really believe we are half way through the quarter already?
Today we discussed more about X-ray diffraction and went over some key details of what you need in order to interpret an XRD pattern.
WHEN INTERPRETING AN XRD PATTERN YOU MUST ACCOUNT FOR EVERY SINGLE PEAK IN THE PATTERN!
I cannot stress that point enough. When we are analyzing whether a solid solution forms or whether the compound is a two phase mixture we need to look at all the peaks in the XRD pattern. Further analysis of the pattern tells us how the unit cell is changing when we replace one ion with another. This leads to an important relationship from Bragg's Law:
As the spacing between planes gets larger the peaks in an XRD pattern shift to lower angle, or shift to the left.
The same relationship holds when the spacing between planes gets smaller, as the peaks shift to the right.
As a chemist, we can manipulate the spacing between the planes by substituting a cation/anion with a smaller or larger atomic radii. By doing this we will be able to influence the bonding and more importantly the color of a compound.
Another thing about X-ray diffraction is that you need to have a crystalline sample in order to obtain a diffraction pattern. When I was talking about X-ray diffraction last quarter I received this e-mail from former student Asher Kay:
"I was watching Alton Brown's Good eats on the food network and he was making fudge. He wanted to study the crystal structure of the finished fudge and got a person who studies crystal structures( I can't remember the name) to use an X-ray Diffractometer, and Bragg's law to study the diffraction pattern. As it turns out the structure is identical to the sugar crystals that were used to make the fudge. Actually, making fudge is a very chemically intensive task. It is very important to control the temperature to make sure the super saturated solution of fudge does not re precipitate in the form of grainy crystals. Also, you cannot allow crystals to form on the sides of the pot or it will be all over."
When the X-ray patterns of the fudge were analyzed, it didn't matter if you had chocolate fudge, peanut butter fudge, or any combination of the two, all the XRD patterns looked the same. The reason for this is that the only crystalline material in the fudge is sugar. Therefore all the peaks will look the same even though the fudge was different. This story helps emphasize what information we can obtain from an X-ray diffractometer. We can tell which crystal structures are present and the only samples we can use are crystalline materials.
On Monday we will have a special guest in class and I will finish up on solid solutions and emphasize how they relate to a phase diagram.
Hope everyone has a great weekend, Dr. Fus
Today we discussed more about X-ray diffraction and went over some key details of what you need in order to interpret an XRD pattern.
WHEN INTERPRETING AN XRD PATTERN YOU MUST ACCOUNT FOR EVERY SINGLE PEAK IN THE PATTERN!
I cannot stress that point enough. When we are analyzing whether a solid solution forms or whether the compound is a two phase mixture we need to look at all the peaks in the XRD pattern. Further analysis of the pattern tells us how the unit cell is changing when we replace one ion with another. This leads to an important relationship from Bragg's Law:
As the spacing between planes gets larger the peaks in an XRD pattern shift to lower angle, or shift to the left.
The same relationship holds when the spacing between planes gets smaller, as the peaks shift to the right.
As a chemist, we can manipulate the spacing between the planes by substituting a cation/anion with a smaller or larger atomic radii. By doing this we will be able to influence the bonding and more importantly the color of a compound.
Another thing about X-ray diffraction is that you need to have a crystalline sample in order to obtain a diffraction pattern. When I was talking about X-ray diffraction last quarter I received this e-mail from former student Asher Kay:
"I was watching Alton Brown's Good eats on the food network and he was making fudge. He wanted to study the crystal structure of the finished fudge and got a person who studies crystal structures( I can't remember the name) to use an X-ray Diffractometer, and Bragg's law to study the diffraction pattern. As it turns out the structure is identical to the sugar crystals that were used to make the fudge. Actually, making fudge is a very chemically intensive task. It is very important to control the temperature to make sure the super saturated solution of fudge does not re precipitate in the form of grainy crystals. Also, you cannot allow crystals to form on the sides of the pot or it will be all over."
When the X-ray patterns of the fudge were analyzed, it didn't matter if you had chocolate fudge, peanut butter fudge, or any combination of the two, all the XRD patterns looked the same. The reason for this is that the only crystalline material in the fudge is sugar. Therefore all the peaks will look the same even though the fudge was different. This story helps emphasize what information we can obtain from an X-ray diffractometer. We can tell which crystal structures are present and the only samples we can use are crystalline materials.
On Monday we will have a special guest in class and I will finish up on solid solutions and emphasize how they relate to a phase diagram.
Hope everyone has a great weekend, Dr. Fus
Lecture #14, Wednesday, April 29, 2009
The exam #1 average was a 63.1%. It was a very difficult exam and I was pleased by the results of most students.
We continued on with X-ray diffraction and REEL labs #2 and #3. In REEL #2 we first introduced the concept of diffraction. To learn a little bit more about the concept of diffraction I send you to this youtube link featuring University of Minnesota physics professor Jim Kakalious, who was a science consultant for the Warner Brothers film Watchmen. In Watchman Dr. Manhattan has amazing super powers. Dr. Kakalious outlines which physics phenomena are responsible for these super powers. In the movie Dr. Manhattan can appear in more than one place at once and Kakalious asks how he could possible do this. This can be explained by discussing diffraction. At the 2 min 10 sec mark in the clip diffraction is discussed, which is a signature of the wave phenomena of light.
The one thing I want to emphasize is how on earth can a collection of dots from a diffraction pattern relate to structures of solids. Diffraction can tell us the similarities and differences on the slides we used in the optical diffraction part of REEL #2. X-rays can be used to do the same thing with a crystal structure. X-ray diffraction will tell us what structure or structures are present in a given sample and when we progress to REEL 3 & 4 this will be very important to determine.
On Friday's lecture we will start talking about solid solutions and how they are formed.
We continued on with X-ray diffraction and REEL labs #2 and #3. In REEL #2 we first introduced the concept of diffraction. To learn a little bit more about the concept of diffraction I send you to this youtube link featuring University of Minnesota physics professor Jim Kakalious, who was a science consultant for the Warner Brothers film Watchmen. In Watchman Dr. Manhattan has amazing super powers. Dr. Kakalious outlines which physics phenomena are responsible for these super powers. In the movie Dr. Manhattan can appear in more than one place at once and Kakalious asks how he could possible do this. This can be explained by discussing diffraction. At the 2 min 10 sec mark in the clip diffraction is discussed, which is a signature of the wave phenomena of light.
The one thing I want to emphasize is how on earth can a collection of dots from a diffraction pattern relate to structures of solids. Diffraction can tell us the similarities and differences on the slides we used in the optical diffraction part of REEL #2. X-rays can be used to do the same thing with a crystal structure. X-ray diffraction will tell us what structure or structures are present in a given sample and when we progress to REEL 3 & 4 this will be very important to determine.
On Friday's lecture we will start talking about solid solutions and how they are formed.
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