Week 1 - Brainstorming ideas

WEEK 1 - BRAINSTORMING IDEAS

Group name 

Team Sotong

Lecturer

Dr. Woon Kai Lin

Group member

1) Chiam Han Cheng SIB150009

2) Nurul Syahirah Binti Jaffril SIB150043

3) Nur Aqilah bt Meor Ruslan SIB150034

4) Ong Gerard SIB150044

5) Nur Izzati Arina bt Zahari SIB150038

During this week, our team has decided to have a brainstorming ideas session of the experiment that we are going to do. We have discusssed in our whatsapp group, sharing links and videos of some experiments that are related to our course. This is our first draft of the experiment that we are going to do; Polarizing microscope.

Our draft for this experiment

Therefore, as this blog may be viewed by viewers with science background or non-science background, it is therefore necessary to have some brief introduction about "What exactly is a polarizing microscope".

The diagram shown above is how a monocular polarizing microscope looks like.

Before we start, there is a term called "Birefringence" that we should all know before understanding further. "Birefringence" is actually an optical properties of certain material that having a more than one refractive index, depending on the polarization and also propagation direction of light. Example is the CaCO3 calcite shown below.

As can be seen, when a pencil is viewed through the calcite, two images are formed, this is due to the different refractive index exhibited by the calcite depending on it's internal structure that causes different polarization and also propagation direction of light. 

Now, The function of polarized light microscope is to observe specimens or samples that are visible primarily due to their optically an-isotropic character or also known as birefringent properties. The component and structure of this microscope consist mainly of a polarizer, analyzer (a term for another polarizer), which are positioned between the light source and also the ocular lens we use to observe the specimen. Diagram below shows the internal component and also outer structure of a polarized light microscope.

The working theory of the polarized microscope is that is create a contrast in the doubly refracting specimen to differentiate the qualitative and quantitative aspects of crystallographic axes that are present in the sample. Below are the more detailed working theory of the polarized light microscope.

The light that we see everyday are mostly unpolarized, which means that light is actually an electric field travelling in various direction of vector, as to be seen from the incident beam shown above. The first polarizer will filter the electric field from the incident beam and allowing only certain light wave to pass through, depending on the orientation of the polarizer. The light that are filtered is said to be polarized with respect to the direction of  propagation and all waves vibrate in the same plane. 

When the unpolarized light source passed through the first polarizer, it will be "forced" to only vibrating in a single plane, the polarized light then pass through the birefringence sample and results in two component light wave due to the unique optical property of the sample, analyzer then function to filter the two-component-light-wave and causes a retardation, thus creating image with contrast for us to view directly from the ocular lens or camera.

Therefore, our team's (Team Sotong) open lab experiment is to create a polarizing microscope using the material from our surroundings using the theory and working principles as explained above and the one that can be viewed directly from our smartphone!

        Sounds exciting, right? 😉

 Stay tuned on our blog for our team progression and updates!  

XOXO 💘,

Team Sotong