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Showing posts from March, 2020

A Lecture on Greenhouse Gases

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Greenhouse Gases: Lecture I
Chem 002
Angel C. de Dios
Chemistry of the Environment (Greenhouse Effect)"The Earth system follows laws which scientists strive to understand," 
said Dr. F. Sherwood Rowland, a Nobel laureate in chemistry.
"The public deserves rational decisionmaking based on the best scientific advice about what is likely to happen, not what political entities might wish to happen."
From: Preeminent Scientists Protest Bush Administration's Misuse of Science



When I first added "Greenhouse Gases" as a topic in my General Chemistry, I shared with another Filipino American scientist the slides I prepared for that first lecture. This was back in 2008 and the following was his response.
My son, Alexander, was two years old then. I took the following photos when he was just several months old.
Yes, there are 13 questions in the next homework on Sapling. These are due a week from now, but I would like you to work on the first 13 questions before this w…

As We Move to Distance Learning

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Fairfax County School Superintendent Scott Brabrand shared today with parents via email the district's plan for distance learning. With schools closed due to the current COVID-19 pandemic, learning can only continue inside children's homes. In the email, the following provides briefly what is inside the distance learning plan: "The plan includes paper learning packets, video broadcasts, lessons/assignments and learning materials posted to Blackboard and completed individually or collaboratively, along with scheduled web chats." Related to this, Education Week has recently shared a quiz on personalized learning. One of the questions in the quiz is quite meaningful. And I answered it correctly, as my daughter and I paid her school a visit this afternoon.


The specific question is the quiz is as follows:


Since a great majority of those who took the quiz answered the question on how teachers become familiar with their students' lives outside school incorrectly, it may…

Are We Doing What Needs to Be Done?

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Amid the current crisis, we do need to look at some positive sign. People are recovering. We can see this in the following graph. This is encouraging yet we know that we must still take action. Unfortunately, the question, "Are we doing what needs to be done", remains challenging especially for our leaders. Of course, there are actions that are obviously urgent. These include providing protection to our health workers. They need masks and disinfectants now, and not tomorrow. Hospitals need supplies likewise at this moment, and not in the future. These are the actions that are needed now, yet, what our leaders, it seems to me, are currently faster in achieving, is giving orders that place a substantial pause in our daily lives.


Just a couple of hours ago, the governor of Virginia has ordered schools to be closed until the end of the academic year. The school board of Fairfax county is scheduled to meet soon, I guess, to figure what can be done for learning continuity. Without…

Coronavirus Cases

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Giving lectures online is so different from teaching inside a classroom. That is still an understatement. These are difficult times for teachers and students. Yesterday, I received a note from one of my students that made me feel both happy and sad:
Also, we all miss you a lot, too. It's not the best situation, but at least we still get to study chemistry, even if it is from home. My students are indeed still studying chemistry. And we could hope that they are still learning. But it is hard to focus on the material with so much going on outside. After all, it is not just the health status that we worry, but also the economy. I am currently covering kinetics in my General Chemistry class. This is the study of how fast chemical reactions occur so I could not avoid the fact that we are dealing with an unsettling dynamic situation in the world. This is how I started my lecture yesterday:

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Right now, we have these questions regarding the corona virus. How fast does…

Virginia: No Standardized Testing This Spring

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My fifth grader and eight grader do not know this piece of news yet but, apparently, the state of Virginia is planning to cancel the Standards of Learning (SOL) tests this Spring. This requires approval from the federal government since the state is required to administer these tests so the cancellation is not final yet.


Unlike the Nation's Report Card, which samples schools and students, Virginia SOL tests are required for all students. In order to graduate from high school 12th grade students need to pass these tests. A standardized test being used as a requirement for graduation does not make sense. It only highlights our lack in trust in teachers, who are in a much better position to assess where their students are. Standardized exams are like taking the pulse, a teacher's assessment is like an executive physical check-up. With the school closures, cancellation of standardized exams will take a huge load off the shoulders of both students and teachers. This will provide a …

COVID-19: A Lesson in Numbers

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Our World in Data reports that there have been 4831 COVID-19 tests performed per million people in South Korea. The number of COVID-19 cases in South Korea currently stands at 159 per million people. Assuming that there is ample testing in Korea, the rate of positive COVID-19 tests is around 3 percent. This infection rate looks very promising. There is another piece of data that is equally reliable and this is the case of the cruise ship Diamond Princess, where virtually everyone has been tested. 696 out of 3711 people aboard this ship tested positive for the virus. This means a little less than 20 percent got infected. This is probably the worst case scenario since a cruise ship is similar to a Petri dish. The current fatality rate from the novel coronavirus for South Korea stands at about 0.9 percent, while for the cruise ship, it is 1 percent.  Thus, we have a range of numbers, for infection rate, South Korea provides 3 percent, and the cruise ship gives the worst case scenario of …

CDC Recommendations for ("against") School Closures in Response to COVID-19

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The US Centers for Disease Control and Prevention (CDC) has issued recommendations or considerations regarding school closure. The considerations based on data from other countries suggest that school closures will probably have no impact on how fast COVID-19 would spread. The CDC states, "Available modeling data indicate that early, short to medium closures do not impact the epi curve of COVID-19 or available health care measures (e.g., hospitalizations). There may be some impact of much longer closures (8 weeks, 20 weeks) further into community spread, but that modelling also shows that other mitigation efforts (e.g., handwashing, home isolation) have more impact on both spread of disease and health care measures.  In other countries, those places who closed school (e.g., Hong Kong) have not had more success in reducing spread than those that did not (e.g., Singapore)."

Before this past Thursday evening, the Fairfax County Public School (FCPS) District is actually followin…

Reactive or Proactive: Fairfax County Schools' Decision-Making

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The novel coronavirus is truly new in so many aspects. Data currently available indicate that children do get infected, but exhibit only mild symptoms. Data from China suggest that children can be transmitters of the virus. Infections of the virus among children, however, remain low. Thus, COVID-19, the disease caused by the novel coronavirus, is markedly different from influenza. Yet, how effective nonpharmaceutical interventions such as school closure are to delaying and minimizing an epidemic is based on what we know regarding influenza. Thus, a proactive measure at this point truly requires guidance from health officials. Fairfax county, in its update late yesterday afternoon, noted that schools would be closed on Monday to give teachers the opportunity to prepare for distance learning in case schools are closed. They did not announce that schools were closing today. Late in the evening, the superintendent decided to close schools. The decision was visibly influenced by parents an…

Lessons on Coronavirus

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While Princeton University has moved to virtual instruction up till April 5, Sarah Schwartz shares in EducationWeek lesson plans for science, math, and media literacy from K-12 schools. One lesson graphs world data on Coronavirus from the World Health Organization. Another looks at possible sparks of prejudice against Asians because of the outbreak and why such a reaction has no scientific basis. And a third one encourages not just to repeat what is seen in social media, but actually evaluate whether these are simply exaggerated or real.


The current outbreak is a real threat but during these times, reliable information is a must. There are a lot of numbers involved so the data do provide an opportunity to construct math lessons. Take, for instance the following graph that explains why slowing down an epidemic is helpful.



The above illustrates how nonpharmaceutical interventions (frequent washing of hands, staying home if one is not feeling well, covering coughs and sneezes, social dis…

Amidst the Spread of Coronavirus, Should the Philippines Close Its Schools?

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The mayor of Navotas in the Philippines actually suggested not just a closure but the granting of passing grades to all students for the current school year. The end of the school year in the Philippines is April 3, about a month from now. Navotas has no recorded case of coronavirus infection so the suggestion is part of a preventive measure. Italy and Japan have closed schools but these countries have far more known cases than the Philippines does. Whether school closures are beneficial or not is an important question to raise. In the Philippines where online learning is not accessible to all, education pays a hefty price if schools are closed. Experts provide some specific guidelines on when it may be good to close schools: If five percent of students are absent in one day, it maybe wise to close schools. The point here is that it should be clear that there is an active transmission of the disease in the community, therefore, it is not a decision that should be taken lightly. In thi…

Let Students See What We Mean

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Language could be a barrier. I remember in college the first time I heard the word "stochastic". Wow! I had no idea then what that word meant. And that word had a significant weight on what the instructor was trying to tell me. I wished the instructor had just used the more familiar synonym, "random". I probably would have understood more. It is true that science requires precise and accurate language, but in a lot of cases, it is possible to use more familiar words instead of low-frequency but non-technical words. Chemistry requires the use of the word "covalent", but it does not require the use of the word "commensurate" in place of the word "equal". In a classroom where students' needs ought to be considered, we must try our best to help children succeed, and not add unnecessary hurdles to learning. In science, this is particularly important especially when the students are not native speakers of the medium of instruction.

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