VSEPR is a model used in Chemistry in order to predict a geometric shape of molecules based on the number of valence electrons. 

We can classify molecules into 7 main geometric shapes:

  • Linear                                      180°                    Non-Polar
  • Bent                                         104.5°                Polar
  • Trigonal Planar                   120°                    Non-Polar
  • Trigonal Pyramidal           107.3°                Polar
  • Tetrahedral                          109.5°                Non-Polar
  • Trigonal Bipyramidal       90°/ 120°         Non-Polar
  • Octahedral                           90°                      Non-Polar

Before figuring out any of those shapes, we need to draw Lewis Dot Diagram first. Let’s look at some examples:


Based on its Lewis Dot structure, we can classify HCN as Linear. 

As you can see above, Sulfur has 5 bonds. So, we would classify this as Trigonal Bipyramidal. 

Now, in this case, Sulfur has only 2 bonds. We would classify this as Bent. Why? HCN also has only 2 bonds but classified as Linear. That is because there are two extra pairs of electrons in the middle atom so those two pairs of electrons will push each of the two bonds down, creating an angle. 


After the incredible physics course last year, we’re now taking an introductory chemistry class with our new facilitator. 

We’re going through lessons such as scientific methods, isotopes, moles, ions, electron configuration, and emissions. 

Our latest lesson was on emission; we learned how atoms emitted energy to visible colors when it becomes excited.  So, let’s break it down. Throughout history, scientists had been debating whether lights act as waves or particles. But, in this unit, we’re learning when lights act as waves. Ok, what does that have to do with emissions? So, when some amount of energy hits an atom, some of its electrons become excited and jump to a higher energy orbital or excited state. Then, those excited electrons will release the energy as photons which are the visible colors and jumped back to its ground state. Those visible colors are release with different wavelengths that produce different colors. 

We also did a flame test lab on this lesson. It’s fun because..we get to wear those lab coats and it looks cool. Actually, there’s more than that. First of all, we lit up the Bunsen burner with lighters, then we put the different compounds of chloride and see observe the changes in the flame colors. Those compounds are barium, calcium, copper II, lithium, potassium, strontium, and an unknown #1. Then, we have to record all the data of different compounds and write a lab report for it.

My personal favorite is copper II:

This is the color produced when copper II reacted with flame


Physics Behind Dr. Strange’s superpowers

Doctor Strange

Dr. Stephen Strange known as Dr. Strange is a fictional character appeared in the Marvel Comics and debuted in 2016 as one of the superheroes in the Marvel Cinematic Universe. His first movie, “Doctor Strange” initially released on November 4, 2016, was a successful science fiction movie starring very passionate actors and very quality content. In the movie, Dr. Strange suffered from a severe traffic accident caused him to broke both of his hands. Then, he decided to go on the journey of finding a cure to his broken hands; his last choice was to get a mystic healer from the “Ancient One”. In the process of healing; he’s also learning mystical arts from the ancient one, gaining his superpowers in various ways in order to protect this universe. All of his superpowers seem like magic; however, it isn’t really magic; therefore, let’s go debunk Dr. Strange’s superpowers by science!

Astral Projection

One of Dr. Strange best superpowers is Astral Projection. Astral projection is allowing your body to travel in a spirit form. To do that, one must be separated completely from the physical form. However, this is not really a scientific event that can be proved, but rather a psychological theory. Nevertheless, this superpower is fantastic in a sense that it can allow you do different things in your body form and your spirit form. This might happen a lot to those who usually do meditation.

The Eye of Agamotto

An incredible item that wore by Dr. Strange is the eye of agamotto. It allows for time manipulation, dimensional travel, and see through illusions and lies. As seen in one of Dr. Strange’s scenes; he has the ability to travel through a hole and appear in another place and that is called “Dimensional Travel”. The eye of agamotto makes that happen! According to a physicist Lisa Randall, “the only possible interaction between dimensions is through particles.” In the movie, Dr. Strange manipulates the particles inside the eye of agamotto that can hop into other dimensions, then those particles can create a black hole for him to travel through! Since we know that particle is the only way to interact between dimension, it is possible for dimensional travel if we can manipulate those particles.

As said that the eye of agamotto can also enable the user to see through the illusion. For example, one of the scenes showed the illusion of a city in various dimensions:

People might question what are these weird dimensions of the city. To explain, Ancient one once said, “We harness energy and shape reality.” This illusion is not magic and so does every magician, they did not create something that is “magic” instead they “shape the reality” for people to fall for. There’s no such thing called “magic”; however, because our perception is limited, magicians are trying to shape and alter it so that we believe in it. They did not change reality, only perceptions did. That same thing applies to Dr. Strange’s ability to see through the illusion, the image above is neither upside down or sideway; however, it “appears that way through a refracted repeating image.” So, how do they shape reality? Well, when Dr. Strange first met with the Ancient One, he saw crystal lights. It started with photons; according to a scientist Mikhail Lucan, “They created a special medium in which photons interacted so strongly that they began to act as though they had mass and banded together.” When photons interact so strongly, it becomes atoms, then they become solidified light or light crystals. When Dr. Strange first knows how to use his power he created a crystal wall:  

As you can see here, there are multiple Dr. Strange’s faces on that wall which basically means it is refracted repeating image. In addition, the city’s image case is when it happens on a bigger scale!

Cloak of Levitation

Last but not least, an item that is worn by Dr. Strange is the cloak of levitation. It is capable of giving its master the ability to fly, providing aids and assistance during battle, and even have emotional feeling and affection with its master! Well, that’s unexplainable. There is a possible chance that the cloak is made out of a unique material that allows that master to fly; however, having affection and feelings are sort of magic since it is not a living object. It doesn’t really follow any science rules and that is normal for movies. In order for any science fiction movie to look incredible, something in it have to look impossible!

To sum up, Dr. Strange is capable of doing awesome super powers and following physics rules. At the same time, the MCU is a really well-known company of creating powers that are relevant to our science rules and using it as an entertainment and also education for all ages.


Works Cited

“Doctor Strange’s CLOAK OF LEVITATION Explained! (MCU).” YouTube, YouTube, 10 June 2017, www.youtube.com/watch?v=UBgQqBOMhQ0.

FilmTheorists. “Film Theory: Doctor Strange Magic DEBUNKED by Science.” YouTube, YouTube, 16 Nov. 2016, www.youtube.com/watch?v=drXGJ3ZZdvc.

Hybrid0027. “How Doctor Strange Travels Dimensions | Super Science.” YouTube, YouTube, 22 Oct. 2016, www.youtube.com/watch?v=wo-NIaomDr8.

“The INFINITY STONES: Part 6 | The Time Stone (MCU).” YouTube, YouTube, 1 Mar. 2017, www.youtube.com/watch?v=164lpEx2Vw0.

“What Are DOCTOR STRANGE’S Powers?” YouTube, YouTube, 3 Oct. 2016, www.youtube.com/watch?v=PwZK6YGdD8U.

fluidicbeats. “The Powers of Doctor Strange Explained.” YouTube, YouTube, 3 Nov. 2016, www.youtube.com/watch?v=2b_61_RdOw8.

Women in STEM

Image result for rachel carson
In Physics, we’ve talked a lot about women in STEM; therefore, we assigned to write a biography of one female scientist in our own fields.


Rachel Louise Carson or Rachel Carson (May 27, 1907 – April 14, 1964) was an American marine biologist, author, and conservationist who fell in nature and ocean in her whole life. Rachel grew up in a simple family in the rural river town of Springdale, Pennsylvania, just up the Allegheny River from Pittsburgh. She was a daughter of Maria Frazier (Mclean) and Robert Warden Carson, an insurance salesman. Unfortunately, she died on April 14, 1964 (Aged 56) at Silver Spring, Maryland, the U.S. due to Breast Cancer.


Rachel Carson joined Pennsylvania college, currently known as Chatham University from 1925-1929, originally going to major in English, but changed and graduated as a biologist. She then continued to prior her knowledge of biology by majored in zoology and genetics at Johns Hopkins University (1929-1932).


Carson did not pursue any relationship as husband and wife; however, she has a very good friendship with her best friend, Dorothy Freeman. This solid friendship lasts for the rest of her life and they mostly communicated by letters. Over the course of 12 years, they’ve exchanged approximately around 900 letters.  

Early Career and Publications

Carson took a position as an aquatic biologist which she had to analyze, report field data on fish populations, to write brochures and other pieces of literature for the public for the U.S. Bureau of Fisheries. She remained in the U.S. Bureau of Fisheries also known as U.S. Fish and Wildlife Service until 1952.

She then continued in her path of biology by being a member of the MBL (Marine Biology Laboratory) corporation from 1952 until her death.

Beginning in the 1940s, Carson and other scientists grew concerned about government pest-control programs that used DDT and other synthetic chemicals. Those chemicals hurt far more species than just mosquitoes and fire ants. Silent Spring, which took its title from Carson’s fear of a spring without chirping birds, played a large role in inspiring the modern environmental movement regarding this issue.


Carson was well-known for her writings on environmental pollutions and natural history of the ocean.

She became an author of four books includes:

  • Under the Sea Wind (1941)

Under the Sea Wind was Carson’s first remarkable work celebrating the mysteries and beauties of birds and sea creatures in their habitats. It is well-known as one of America’s greatest nature masterpiece.

  • The Sea Around Us (1951)

The Sea Around Us preceded by Under the Sea Wind was a prize-winning and best-selling book by this best-known author in nature. This book articulated the importance of our watery globe. She explained mountains and canyons secrecy hiding below the ocean and how they were found. She continued to further introduce us to islands, global winds, rain, currents, and tides. She merged her writing with imaginations, facts, and expert knowledge. This book made her become an international writer of nature and ocean’s significance.

  • The Edge of the Sea (1955)

The Edge of the Sea has always been a book that Rachel wanted to write about. It’s a guidebook to the ocean; however, it turned out to be more than just a guidebook. It introduced a world of teeming life where the sea meets the land. A scientifically accurate exploration of the ecology of Atlantic seashore and what we can find at the edge of the sea.

  • Silent Spring (1962)

Silent Spring is an environmental science book that documented adverse effects of pesticide used. She accused the chemical industry of spreading misinformation for the world to accept the use of pesticides.

Unfortunately, Carson died two years after Silent Spring published. She died before she could see any substantive results from her work on this issue, but she left behind some of the most influential environmental writings ever published. Her silent inspiration through writings is witnessed by the world by celebrating ‘Earth Day’ every April 22 and establishing a program called Responsible Care by the Chemical Manufacturers Association (now American Chemistry Council) in 1988, to help the chemical industry improve its safe management of chemicals from manufacture to disposal.



Through weeks of learning kinematics, static equilibrium, dealing problems with motion. We’ve moved to focus on momentum. Momentum is how much motion an object has. The equation for momentum is P: MV which M stands for mass and V stands for velocity. Its unit is kg m/s. Furthermore, momentum is a vector as well. We have so many problems related to momentum. To expand this idea, we also have Law of conservation of momentum which is articulate the idea that total momentum will be the same before and after a collision. This law of conservation is true only in a closed system. A closed system is a system where is no external force that acting on an object. Talking about momentum, we shall never forget collision! The collision takes a really main point in momentum. For instance, here are some examples we’ve done:

Physics Behind Everyday Activities

In physics class, we have a pause from equations, solving problems, inclined planes; however, change the topic to look at physics behind everyday activities. Our task before and after water festival holiday is to research of physics behind everyday activities. We chose our own topic to research on and present it to the class after the holiday. My partner and I had chosen the physics behind mirrors. We have to research the physics of mirrors like – what kind of law is it apply to..etc. Since this task is asked to research and do on our own, there are many contents that we haven’t learn yet. We’ve tried our best to deliver a simpler explanation of the physics of mirror. We didn’t get very deep into it because we don’t have enough time, furthermore, it’s complicated.

We have researched and found out that physics of mirrors involved in two laws including the law of reflection and conservation of energy. We also choose an important question about mirror: Do mirrors flip us horizontally and vertically? Ever wonder when you raise your right hand, the mirror raises your left hand; however, why don’t mirror flip us upside down when we stand upright. In the presentation, we covered law of reflection, conservation of energy, and how a mirror works especially does mirror flip us?

You can access more explanation of this research by this link:

Physics Behind Mirror


One of our main curriculums is essential which contains all the main and important classes including Math, Physics, Khmer Literacy and English literacy. One of my favorite subjects is physics. First Lesson that we’ve learned is kinematics that talk about dealing problems with motions. We have learned kinematics, static equilibrium, static friction and kinetic friction. Physics is complicated, but when we develop those skills such as problem-solving and have the knowledge to understand the concept or theories of physics. We are sure inept in it. Our teacher gives homework and quizzes which makes us even more adept at solving those problems.

Here is an example problem that we’ve done: