Doppler Effects of Meteorology


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Doppler effects are used in many types of technology, and this is one example of using Doppler effects to work meteorology. The common design of the weather radar is a radar that covers with the sphere material around it (we can find this in Cambodia, it’s after the Chbar Ampov bridge there is a big ball and there is a radar inside there). The full word of radar is RAdio Detecting And Ranging. Doppler radar has a transmitter and a receiver. The transmitter transmits microwaves in 360 degrees into the atmosphere, and then the receiver is waiting to receive those signal that will return back. The signals that receive is called the radar echo. Precipitation is the one that reflects the microwaves back. The information that the receiver receives is in two form: relative and velocity. Relative tells where the precipitation is; the velocity, happens only in the Doppler radar, output the velocity of the wind. If the frequency is high the precipitation is moving toward the radar; if the frequency low the precipitation is moving away from the radar. Here is an example, “If particles switch from moving toward and then away from the Doppler radar over a small distance, the source may be a tornado.” As a result, Doppler effects benefits a lot to human, the concepts can save people’s life from storms like a tornado.

Edith Clarke – The Clarke Calculator


Edith Clarke was born on February 10, 1883, in a farming region near Ellicott City, United States. In her childhood life, it was a bit different from others; at the age of seven her father passed away while five years later her mom passed away. So then her uncle was become her guardian legally and sent her to a boarding school.

Educations and Jobs:

After finish high school at the age of 18, Clarke continues her study journey at the Vassar College in Poughkeepsie, New York. In the college, math and astronomy was Clarke’s degree. In 1908 she finished her college and begin her life as a teacher in a private girls’ school in San Francisco and after that, she taught in Marshall College.

After a few years of teaching, Clarke decided to return back to school and continue another degree in civil engineering at the University of Wisconsin in 1911. At the end of the first year at Wisconsin university, Clarke finds a summer job as “Computer Assistant” art AT&T. During the job, Clarke got addicted to it and quit school to have a full-time work at AT&T.

While working at AT&T Clarke love learning and spent her free time to learn in colleges and university. Some of the degree that she took were radio at Hunter College and electrical engineering at Columbia University.

Seven years later, Edith Clarke changes her journey in continuing her study as a master degree in electrical engineering at Massachusetts Institute of Technology (MIT). After graduated in master degree from MIT, Clarke enrolled in a company calls General Electric (GE) as a role in computer. But in 1921, she left GE and went to be a physics professor in Constantinople Women’s College in Turkey; in 1922 she returned back to GE and work as an electrical engineer. After 26 years of working at GE Clarke shifted her career working as a teacher at the University of Texas.


One of Edith Clarke famous inventions calls, the Clarke Calculator. Historically electric power has a lot of limitation in transmitting to a long distance. Before the Clarke Calculation, the electrical transmission line can go few miles like 50 miles; in Clarke’s report stated, “accuracy is desired in calculations for long lines.” From the quote that stated in Clarke’s report meant that, after her calculator was found, the transmission line can go for long distance like 200 miles and a better accuracy. In 1921 while Clarke was working in the GE, she was found out a mathematical technique that calculates for a long distance transmission line; her mathematical technique is given power system and its behavior the technique is called symmetrical components. From that time on transmission line were getting longer and longer with more and more accurate.

After Edith Clarke had found the invention, she began to write a paperwork to the American Institute of Electrical Engineers (AIEE) in 1926. Clarke was the first woman who submits the paperwork to AIEE and the first woman to be elected the as a fellow of Institute of Electrical and Electronic Engineers, IEEE.

The First:

In the past, there were not much of women involving in STEM, but Clarke has a lot of interests in STEM and become one of those women who changed the perspective of women in STEM. Based on different websites, stated that Edith Clarke was the first women who graduated from MIT in 1918. The first women become an electrical engineer professor, the first woman to teach engineering in the University of Texas, and the first woman who were hired in electrical and engineering in the US when she returned back to GE. Throughout her amazing works that she had made and revolutionize the world, she received a Society of Women Engineers Achievement Award.



Physic Problem Incline Plan

Incline place is what we currently learning about in physic! I felt a bit stress on this class because physic doesn’t working well with me, not like my older brother who got 6th place in Cambodia on physics. Even though, I still have a determination on doing it and sometime in class I love doing physic and happy to finish the works.


“A 6 kg box is resting on an inclined plane made of wood. The coefficient of static friction of the wood (s) is 0.3. What is the minimum angle at which the box will start moving? (remember the problem I showed you in class! Draw all the forces acting on the box, and please show all the work. Does the minimum angle depend on the mass of the box?”