Crystal Defects

Crystal defects is an imperfections in regular geometrical arrangements of atoms in a crystalline solid. There are 3 type of crystal defects:

1. Point defects

• Point defects are localised imperfections in crystals.
• There are three types of point defect.
• The simplest type of point defect is formed when atoms are missing from the lattice, leaving a hole, this is known as a vacancy.

 

• Alloying elements can dissolve in the basic metal in two ways. They can replace host atoms in the lattice, which creates a substitutional solid solution. The substitute or impurity atom is often larger than the atoms of the host material. This means there are strains imposed on the lattice.  

• Alternatively they may fit in the small spaces or chinks between the atoms of the host material (known as interstitial sites) creating an interstitial solid solution. Interstitial atoms are much smaller than the host material- however they are usually bigger than the interstitial site so the lattice must deform to accomodate them.

      2. Linear defects

• Linear defects occur when a crystal structure contains misaligned planes of atoms. They are referred to as dislocations since atoms are ‘dislocated’ from their position in the lattice.
• An edge dislocation occurs when an extra half plane of atoms exists in the lattice.

• The second type of dislocation is known as a screw dislocation, this is caused by a misalignment of atoms. The motion of a screw dislocation is also a result of shear stress, but the defect line movement is perpendicular to direction of the stress and the atom displacement, rather than parallel.

      3. Planar defects

• A Planar defect is a discontinuity of the perfect crystal structure across a plane.
• A grain boundaries is a general planar defect that separates regions of different crystalline orientation within a polycrystalline solid. Grain boundaries are usually the result of uneven growth when the solid is crystallising.

• A disruption of the long-range stacking sequence can produce two other common types of crystal defects, a stacking fault and a twin region. A change in the stacking sequence over a few atomic spacing produces a stacking fault whereas a change over many atomic spacing produces a Twin region. A stacking fault is a one or two layer interruption in the stacking sequence of atom planes. Stacking faults occur in a number of crystal structures, but it is easiest to see how they occur in close packed structures.

Sultan Idris Education University

UPSI was once known by the name Sultan Idris Teaching College (SITC) back in 1922. It was inaugurated by Sir W. Geogre Maxwell, the head secretary of Malay states associate on 29 November 1922.

UPSI have 2 main campus situated far from each other but still in Tanjung Malim, Perak. 4 colleges known as KZ, KAB, KHAR and KUO. The new campus finished last year and started to be functioning from then on. Our Mathematics and Science Department also moved to the new site.

New block on new campus

Another block

court at old campus

UPSI

New Campus

Main Hall

Week 13 (13 December 2012)

For this week, we are giving opportunity to study and revise physical chemistry because after the class ended we will be having a test. Thus, Mdm Asmayati told us to study for the test. Then, nothing much we did  for the week.

Also, we are given 4 forms to evaluate all of the assignments we've been doing. It's called a Rubric Form. It's require us to give ourselves marks for the assignments.

Last but not least, here a video of How It's Made: Sandpaper

sources: http://www.youtube.com/watch?v=voDJPxQ1CDU

Week 12 (6 December 2012)

For this week, we are having a second test that require us to work in pair and answer a questions about freeware and Web 2.0. What is interesting about this test is that we can make reference and find the answers   by using the internet.

A freeware is a software that is distributed without charge and which may be redistributed without charge by its users. However, ownership is retained by the developer who may change future releases from freeware to a paid product (feeware). One of the examples of freeware is Photoscape.

Tutorial video of Photoscape:

Web 2.0 is a category of new Internet tools and technologies created around the idea that the people who consume media, access the Internet, and use the Web shouldn't passively absorb what's available, rather, they should be active contributors, helping customize media and technology for their own purposes, as well as those of their communities. One example of the Web 2.0 is GeoGebra.

Tutorial video of Geogebra:

source: http://www.youtube.com/watch?v=4q6BuCAMo9U
            http://www.youtube.com/watch?v=Fn6-PoD6lgM

Week 5 (11 October 2012)

The test week (sounds weird). Well, Nothing much that we do on this week actually.  So, there’s nothing much to be said then. Just, the night before it, I’d burn a midnight oil to memorize study for the test,

We've been asked about the smart school, internet ethics and the benefits of internet, pretty much of it, on the test.

Smart school in China:

source: http://www.youtube.com/watch?v=p38vW0BCB-M

Week 11 (29 November 2012)

Mdm Asmayati didn't attend the lecture today because she been away to Malacca for some study business. But, we still need to come to the class, getting the undone assignments done. We submitted the Spreadsheet assignment entitled effect of surface area on the rate of reaction and also the individual video. Also, answered the entire forum in Myguru. 

Here some video of How its made:

source: http://www.youtube.com/watch?v=RYvlU2_8meg

Week 10 (22 October 2012)

After a week been away for a Deepavali's break, class continued. This week, we've study about the CamStudio, a software where you can capture your laptop’s screen. It is not as the Screen Capture thing.

But by this application, we can capture a video from our laptop screen. Awesome right! You can download it from here Camstudio . 

How to use CamStudio?

1. Start Camstudio and go to the "File" menu to start new projects or open old ones. Start a new one.
2. Click on the "Region" menu. This allows you to define the size and area of the screen the program will capture. Click the "Drag Corners to Pan" to move the "Box" around that you will be recording.
3. Select "Options" and click "Video Options." Select the "Compressor." You should use the "DivX" codec from the list. Turn off "Auto Adjust." Set the "Key Frames" to 30, the "Capture Frames" to 50 and the "Playback Rate" to 20. 
4. Finally, go to "Options" and click "Audio Options." Select the "Lame" codec as your audio compressor. You are now ready to record.
5. You can also make a shortcut key on the keyboard to make sure our recording didn't get interrupted. Select Options > Program Options > Keyboard Shortcut

Here a video my friend and I had made by using the CamStudio (our assignment).

Week 8 (8 November 2012)

After a week and a half holiday and also a midterm  break, it feels so good to lazy around doing nothing, great to be back to uni’s life. For this week, we learned about what we called Spreadsheet.

Basically, we learned about  what, why when to use spreadsheets, examples of spreadsheets in teaching and learning chemistry, planning chemistry lesson using spreadsheets.

In it simple word/term, spreadsheet also known as Microsoft Excel.  We use it to create graph, pie chart and to analyse some data. It helps so much by saving our time.

An example of Spreadsheet

Also, every one of us needs to find a video that explain a concept in Chemistry and then download it to give to the lecturer.  And it must be a video from Youtube. So I had chosen this video, a video about ionic and covalent bond:

source: http://www.youtube.com/watch?v=WaPxTAeW5e8

Last but not least, a little more information about the Spreadsheet assignment by Mdm Asmayati, you can find it in the notes.

Me and my teammate had choose the effect of surface area on rate of reaction as the title of our Spreadsheet assignment.

Week 6 (18 October 2012)

The lesson continued with a lecture about 3E (Engaging, Empower & Enhancing).  What is 3E? 

It is about how to acts or behave in front of your students, how to communicate with them and also to answer their questions.  Engaging is the first step to attract the students attention or build an interest on the topic we going to teach. After we’ll be able to catch theirs eye, then we move on with the scientific concept by showing them a video perhaps or doing some exercises. That is what we called Empowering student’s understanding.  Finally, how to enhance our students’ understanding? We can tell them, what are the importance of or how we apply the concept on our daily life.

More info on 3E, you can find it on the notes (your rights).

At the end of the class, we’d decided what is the title for our modelling and simulation assignment, which is an Ester.  And it’s need to be done by week 10. So, We have like a month to get it ready.

Also, we need to choose one theme for the e-forum. And by all means, we chose the classroom environment. Then, every each 4 of us need to come out with a short yet simple question that will be discussed on Myguru.

Here a video of How It made:

source: http://www.youtube.com/watch?v=_f7-Eq4H0D8

Week 3 (27 September 2012)

This blog was Born on week 3 during the class. I had never thought of doing a blog before, so I have no idea how to make one. But, thanks to the classmatesss for the help I managed to create this one then.  

We need to think of a name for the blog title and the blog site (I guess). So, then I came up with this title, chemistry’s  riddle, an inspiration I’d  got  from  English class where we have to tell the class a joke or a riddle for  every single week. 

The lists of what to be on the blog are:

•  A brief explanation about Myself
•  Picture of the Blog owner (No editing needed)
•  Career development plan 
•         Teaching Philosophy
•      Links to the Assignments
•  Reflection (every week)
•  Artifacts
•     Learning and Teaching videos

And, Mdm Asmayati will evaluate this blog on week 12 (if I’m not mistaken).

Here a video on how to create a blog:

source: http://www.youtube.com/watch?v=C0eDdVOuEIQ

Week 2 (20 September 2012)

Second week, lesson continued with how to create your own online form, then editing it, and finally analyse it into a table. So, a very simple first step, all we need is a G-mail account.  If you don’t’ have any, just create one. It is in a blink of an eye. 

Next thing is, you need to click the Drive on the above panel. Then, click on the create button, you’ll see a list of option, and click on the form button. See, very simple right? This taught and benefits me very much as I can use the knowledge in the future.

1. Create Gmail account

2. Sign in into Gmail and click on the Drive

3. Click Create and choose form

4. Fill the red circle and click save

5. Choose a theme and click on Apply and Save

6. Copy the URL (blue words) to any site you want to published the form

Before the class ended, Mdm Asmayati explained what we have to do in the preparation of the slideshow. Our group was given a Form 4 & Form 5 Chemistry topic, one of each, Chemical bond for Form 4 and Oxidation and Reduction for Form 5

These were what need to be the content of the slideshow:

• The group member’s name
• The objective of the topic
• A simple example
• Extra information
• An animation
• A video
• A little graphic

This assignment will be passed up on week 5.

Lesson ended