Fourth CSI Lesson :)

For this lesson, we did the flame test. However, before we started any hands-on activities, we were given a handout to teach us about the background knowledge of flame test.

Background on flame test:
Metals change the colour of a flame when they are heated in it. Different metals give different colours to the flame, so flame tests can be used to identify the presence of a particular metal in a sample.
Every atom consists of a nucleus with tiny electrons whizzing around it. The further away from the nucleus they are, the more energy the electrons have. If a metal atom is heated, the electrons closer to the nucleus may gain enough energy to orbit further away from the nucleus. When they fall back closer to the nucleus, they give off this extra energy as light.

Next, we moved on to the practical part of the lesson. We were given a bunsen burner, a metal loop, lab glasses, and powdered samples of: barium, lead, calcium, potassium, copper and sodium. We were to observe the light emitted when putting these powdered samples into the flame using the bunsen burner and the metal loop.

We stuck the metal loop into the containers of powdered samples and took out a little powder. Then we put the metal loop in the flame and different colours were emitted. These were our results:

On the worksheet given, we were also given some questions as food for thought:
1.) How and what is it used for in "Crime scene investigations/ forensic science?"
2.) Is flame test sufficient to identify the trace metal(s) present?
3.) If there are more than one trace metal present, is the flame test still a suitable technique to identify the trace metals?


1.) Flame analysis is based on the physical and chemical principle that atoms after being heated by flame turn to their normal energy state by giving off the excess energy in the form of light. Frequencies of light given off are characteristic for each element. Flame analysis is a qualitative test and is designed to identify the components of a substance or mixture. Quantitative tests measure the amounts of the components in a reaction or substance. The unknown to be subjected to flame analysis is either sprayed into the flame or placed on a thin metal loop, then put into the flame. Volatile elements produce intense colours. For example: sodium, it produces a very bright yellow colour.

However, as useful as it is to forensic analysis, the flame test does not work on all elements.

2.) I don't think the flame test is sufficient to identify the trace metal(s) present because everyone perceives colours differently. If the flame given out seems red to me, it may seem bright orange to another person, so i think that the flame test is insufficient to identify the trace metals because everyone has different perceptions of colours and it will be inaccurate to just identify the trace metals by observing the light emitted by the metal. -> this is my opinion, may not be true though!
Moreover, impurities or contaminants may affect the test results. Sodium, in particular, is present in most compounds and will colour the flame. Sometimes a blue glass is used to filter out the yellow of sodium.

3.) If there are more than one trace metal present, is the flame test still a suitable technique to identify the trace metals? 
No, the test cannot differentiate between all elements. Several metals produce the same flame colour. Some compounds do not change the colour of the flame at all. 

This is a detailed interpretation of the flame test:

Red
Carmine to Magenta: Lithium compounds. Masked by barium or sodium.
Scarlet or Crimson: Strontium compounds. Masked by barium.
Red: Rubidium (unfiltered flame)
Yellow-Red: Calcium compounds. Masked by barium.

Yellow
Gold: Iron
Intense Yellow: Sodium compounds, even in trace amounts. A yellow flame is not indicative of sodium unless it persists and is not intensified by addition of 1% NaCl to the dry compound.

White
Bright White: Magnesium
White-Green: Zinc

Green
Emerald: Copper compounds, other than halides. Thallium.
Bright Green: Boron
Blue-Green: Phosphates, when moistened with H₂SO₄ or B₂O₃.
Faint Green: Antimony and NH₄ compounds.
Yellow-Green: Barium, manganese(II), molybdenum.

Blue
Azure: Lead, selenium, bismuth, cesium, copper(I), CuCl₂ and other copper compounds moistened with hydrochloric acid, indium, lead.
Light Blue: Arsenic and come of its compounds.
Greenish Blue: CuBr₂, antimony

Purple
Violet: Potassium compounds other than borates, phosphates, and silicates. Masked by sodium or lithium.
Lilac to Purple-Red: Potassium, rubidium, and/or cesium in the presence of sodium when viewed through a blue glass.

PHOTOS+VIDEOS:

The powdered samples! :)

Bunsen burner and lighter!

Barium nitrate

Flame test of sodium 

Third CSI Lesson :)

OUR THIRD CSI LESSON!
We did not go through much during this lesson.

For this lesson, we went to the magic lab to do a small pop quiz on fingerprints (basically, what we have learnt so far), and there were also additional questions in the quiz that was based on background knowledge of fingerprints, and not found in our notes/ powerpoint slides. For those questions, we researched for the answers and discovered alot of interesting facts such as the term for the study of fingerprints: dermatoglyphics. I look forward to gaining more of such knowledge! :) 

Second CSI Lesson- Lab work! :)

For this lesson, we got to do some hands-on activities in the lab. We were really excited to get started but before doing any hands-on activities, we had to watch some videos on YouTube to allow us to gain some knowledge of what we will be doing (There's no point doing something when you don't know what the purpose of doing that thing is right...?).

The links to the videos were on the website for CSI lessons' resources and we learnt various methods of identifying, revealing and showing fingerprints on surfaces where fingerprints are printed but cannot be seen with the naked eye. In our previous lesson, we learnt the most basic way of obtaining our fingerprint, which is to put ink on our fingers and print it on paper.

For this lesson, we learnt different methods of revealing fingerprints that cannot be seen with the naked eye. The methods are: iodine fuming, super glue fumes and dusting powder.

Iodine fuming- it is a way to develop prints on porous and non-porous surfaces such as paper, index cards, magazines and cardboard. We were given a strip of paper and all of made our fingers oily by using the oil on our skin (haha gross). Then, the strip of paper is placed into a container with solid iodine. The sublimation of iodine in the closed container will cause iodine vapors to concentrate, then be absorbed by the oil and sweat left behind my human skin. This print is temporary and will be visible as orange/ brown outline. We then cut out our own prints on the strip of paper and stuck it to our worksheet. All the bench members' fingerprints are then inked on that page and labelled as suspects. The fingerprints are then matched to the piece of paper with the temporary print.


Dusting powder- it is way of detecting latent prints. A variety of powders are used in dusting for prints and the powder we used for this lesson is lead powder. This lead powder is obtained by crushing the lead of the pencil using a motar. Then, we made our fingers oily using the oil on our faces and imprinted our fingers on a strip of paper. We then used a brush to brush the lead powder and brushed over the strip of paper to reveal the fingerprints. Next, scotchtape is stuck onto the strip of paper and the fingerprint is transferred onto the scotch tape. Following that, we stuck the scotchtape on a black background in our worksheet.

Superglue fumes- Superglue fuming is a chemical process to reveal latent fingerprints on non-porous items like bottles, firearms, knives, etc. It is by heating superglue, which releases gaseous vapours that adhere to the oily residue of the fingerprint. Firstly, we oiled our fingers and imprinted our fingerprints on a clear piece of plastic. Then we sent it for superglue fuming. Upon development, the fingerprint ridges will appear a white chalky colour. We then each cut out our fingerprint from the clear piece of plastic, and stuck it on a black background in our worksheet.

I think this lesson has been very beneficial as it has brought us up to another level of experimenting and CSI because we get to do hands-on activities. It has built up my knowledge about fingerprinting and I feel like i want to know more about fingerprinting. This is much better than just reading up on notes on fingerprinting.

PHOTOS! :D

Imprint on glass cover with our oily fingers xD 

Brushing the brush with lead powder! 

The lead powder :) 

MORE LEAD POWDER :)

Can't see the fingerprint now yet huh? wait and you'll see ;)

aqilah and i :) 

AFTER BRUSHING- fingerprints are now visible!

sticking fingerprint onto the worksheet! 

IODINE FUMES. the after photo. :) 

orange brownish marks

taking it out of the container! 

Using the magnifying glass to take a closer look:)

Our fingerprints! 

Cacia's fingerprints :) 

GROUP PHOTO 1

GROUP PHOTO 2

First CSI Lesson and powerpoint slides :)

In our first CSI lesson, we learnt various knowledge regarding CSI.

To kickstart our educational journey on CSI, we watched a video which tested our awareness. The video was about a group of people passing basketballs to each other and the question in the video was "How many passes were there?' The answer was 13 and many of us answered correctly. However, our attention was so focused on counting the number of passes that we did not notice another unusual happening which was that a bear was moonwalking past the group of people passing the balls. It was quite interesting as a huge number of us didn't notice that. This shows how unaware we are when we focus on a certain aspect too much. Thus, we learnt to be more vigilant.

After going through all the slides on fingerprints classification briefly, we had a worksheet on fingerprints and each group was given an ink-pad to ink our fingerprints on one page of the worksheet. For that activity, all of us got to see how our fingerprints on different fingers looked like.
However, before we printed our fingerprints on the worksheet, we learnt about the different types of fingerprints. There are whorls, loops and arch types of fingerprints. We learnt that fingerprints are used for identification during crime investigation and for other purposes. We also learnt that no two people have identical fingerprints :)

The activity was quite fun and exciting because i've never really noticed how my fingerprints looked like. But for that lesson, i actually got to see the intricate patterns of my fingerprints and i was instantly intrigued to know more about CSI because it gave me a rough idea of what my upcoming educational journey for CSI would be like. However, during that activity, i had too much ink on some of my fingers and i could not really see some parts of my fingerprints due to the huge blotches of ink. I now know that when doing fingerprinting, it isn't necessary to put so much ink on our fingers because that makes it harder for fingerprinting (Less is more in this case!! :) ). Next, we completed some small activities in class. Our whole group printed their individual fingerprints on the worksheet and we chose someone to be the culprit to print their fingerprint on the paper and all of us to be suspects. Next, we handed the worksheet to other groups to make them guess who the culprit is among all the suspects. It was a fun and exciting activity as some of the groups guessed wrongly and had to make multiple guesses to get the correct answer. I believe that from that experience gained from the activity, they will be able to identify fingerprints more aptly in the future. Some groups also had blotchy and inky fingerprints so it was hard for identification.


Next, we learnt about physical evidence and the examples of physical evidence.
I learnt that physical evidence is factual evidence and cannot be wrong, cannot perjure (willfully tell an untruth when giving evidence to a court- meaning of perjure) itself. Only in its interpretation can there be an error when humans fail to interpret and conclude based on the physical evidence. Examples of physical evidences include: fingerprints, shattered glass, lipstick stains, blood splatter/ blood trails, dirt found on the sole of shoes and tyre marks. Physical evidence is a type of circumstantial evidence. 
Reflection: 
Learning about physical evidences is useful when investigating and exploring the crime scene because with this knowledge of what physical evidence is, we will be more aware of our surroundings when carrying out the investigation and we will know what to look out for to bring back to the lab for more analysis. Thus, we will be able to gather more evidence to aid us in the cracking of the case! :)
This builds up our awareness of our surroundings and increases our knowledge about CSI.


Other than that, we also learnt about other types of evidences. 
Direct evidence- 1st hand observations, eye witness accounts, videos, etc. 
Circumstantial evidence- Indirect, physical or biological evidence that can link a person to a crime, but does not directly prove that the person is guilty. Physical examples: bullets, fibres, etc. Biological examples: body fluids, hair, etc. 
Reflection: 
Learning about different categories of evidence can solve our misconceptions about evidence and CSI. In the future, we will be able to classify the evidences under different categories and be more organized in our investigation. More organization leads to less confusion and thus more efficient and faster investigation. 


Besides that, we also learnt about the people in the crime-scene investigation team. All of them play important roles in aiding the progress of cracking the case. Last but not least, we learnt about the 7 S's of crime scene investigation. These are important procedures that we have to follow in chronological order. They include:
1.) Securing the scene
2.) Separate and question the witness
3.) Scanning the scene
4.) Seeing the scene
5.) Sketching the scene
6.) Searching for evidence
7.) Securing and collecting evidence.

All these steps are essential in crime-scene investigation as they help to gather more evidence, more information regarding the case. And it would be more convenient to sketch the scene (drawn to scale) and take relevant photographs of the scene instead of repeatedly re-visiting the crime scene for more information. All these evidence and information gathered are then brought back to the lab for more analysis and brought back to the headquarters for more interpretations. From there, they will proceed on with cracking the case.

The above information is obtained from the slides posted online by our teacher and it is an introduction to CSI for us to briefly read and go through by ourselves.

Overall, i found the first CSI lesson quite interesting as it gives us a rough idea of what we are going to be doing and it really motivates me to read up more about CSI. I will be looking forward to the upcoming lessons! :)