Lewis structures are used to illustrate the valence electrons of an atom. The video below explains how to make these diagrams using LaTeX. For chemistry students this is a great intro to using LaTeX for completing assignments.
John Dalton was an 18th-century scientist who made several significant contributions to his field. One of his most prominent works was his Atomic theory. Dalton’s Atomic theory is a major concept in the study of chemistry. In this post, we will look at this theory and share some of the misunderstandings that Dalton had at his time.
Atomic Theory
Dalton’s Atomic Theory has four propositions to it.
There is little to explain here. Part one states that atoms cannot be divided or destroyed. In other words, the atom is the fundamental unit of the universe. Part 2 states that all atoms are identical in their properties, which implies that every atom of an element has the same number of protons, neutrons, and electrons.
The third component states that compounds are formed by two or more different atoms. For example, one compound would be H2O which is water. Since there are two elements in H2O, it meets the definition of a compound. We also call such a compound a molecule. Component four states that a chemical reaction is a rearrangement of the atoms in the substance. An example of this would be digestion which involves significant chemical changes to the food.
Problems with Dalton’s Theory
Despite the brilliance of Dalton’s theory, several problems have arisen as researchers have continued to explore the mysteries of chemistry. For example, the first proposition of Dalton states that atoms cannot be divided or destroyed. Both of these claims are false. We now know that atoms are made of protons, neutrons, and electrons. In addition, atoms can be destroyed, which happens at any nuclear power plant through fission. Nuclear fission involves neutrons hitting atoms which causes them to split.
Dalton was also incorrect regarding his second proposition about the same atoms having the same properties. With the discovery of the neutron, it became clear that atoms may have the same chemical properties but not the same physical properties. The reason for this is that having a different number of neutrons affects the atom’s weight. When atoms of the same element have different neutrons, we call these isotopes.
Conclusion
Dalton’s work in the study of atoms is something to be praised. It is understandable that perhaps he got some things wrong. The purpose of science is to grow and improve over time, and this means that sometimes great scientists are right, but they must also be wrong.
Principal component analysis is a tool for reducing the number of variables in a dataset without losing too much information. This is a great way to summarize information or to simplify things for a more complex analysis. The video provides a simple example of how to do this.
Social stratification is the ranking of individuals using various factors such as wealth, income, education, etc. While I was preparing this post, I could not find any evidence of a classless society. In fact, some of the sources claimed that no such society as a classless one has existed. This implies that stratification is a natural part of human existence whether people like it or not.
What causes this is not always apparent. For some reason, people often like to exalt themselves and be above others. There is a tendency in some people to desire control and dominance. Sometimes people are chosen to be the leader or in a higher social position by others in the society. Leaders often fall into this category and can include politicians, clergy, and kings. Others gain a higher status through hard work, and people admire and appreciate this. For example, Napolean was able to rise through the ranks of the military due to his brilliant leadership and eventually became emperor.
There are also examples in history of people gaining power not just for selfish reasons but for personal protection from one’s enemies. Ceaser was truly driven by a desire to rule, but he also had enemies who were waiting for him to lose power so they could attack him through various legal means. Therefore, Ceasar looked for ways to maintain the leadership of provinces and be consul of Rome to maintain his legal immunity. Even when taking power, he generally would grant amnesty to enemies to avoid stirring up more enmity. However, as he became more powerful, he just became even scarier to the other elites who simply murdered him one day.
The best it appears people can hope for without being cynical is a world in which the elite and upper class refrain from abusing and mistreating the people below. There is also little historical evidence of elite restraint as there is almost no evidence of a classless society. Different people put in different amounts of work, and some find different ways to cheat their way, and thus there will always be differences between the ranking of people.
Caste System
There are several terms related to social stratification. The caste system is one. With the caste system, people are born into a certain level of society, and they are stuck there forever. There is no social mobility. Examples of this can be found in India, Feudal Japan, and Medieval Europe.
Marriages between caste are frowned upon or even illegal. For example, a friend from India told me how they got married. She was from the warrior caste, while her future husband was from the priestly caste. Since they were Christian, they did not think they were bound by the tradition of the caste system and for married. Being it was a Christian community, everyone was okay with it; however, several people were still worried that something “bad” might happen to the newlywed couple because of the country’s cultural background. India abolished the caste system, but its roots are still strong in some situations.
Class System and Meritocracy
The class system is a more flexible style of social stratification in which people belong to one of many different classes based on their wealth, education, etc. Examples of classes can include upper, middle, and lower classes. Unlike the caste system, which discourages marriage, the class system does not generally condemn marriages of people from different classes.
Meritocracy is social stratification based on effort. At best, meritocracy has been partially implemented in many places. No matter how hard humans try, people are just good at findings ways of getting through the system without equal work. This leads to frustration by those who “play by the rules.” Another problem is that some people will achieve a great deal in one area, but this area is not valued as important by society.
Highly educated people often have amazing expertise in minute details of life that are not generally valued by the larger society in terms of prestige and financial remuneration. This can lead to frustration and desires to challenge the social stratification. At times, some of the strongest proponents of a classless society are people who do not have the status they believe they deserve.
Conclusion
Stratification is always going to be a problem. This is because people will always find ways to move up the social hierarchy through honest hard work and abuse the system for personal gain. Unfortunately, people may lose status due to mistakes or injustice, and those who are higher up may mistreat those who are lower, which is not fair or right again.
Python has a great library called that Altair that makes it really easy to make various data visualizations. The primary strength of this particular library is how easy it is to use and to also create interactive plots. The video below provides an introduction to using this innovative tool.
Local arrays are a way of storing data in Excel. In this video, we will look at two different ways that you can place data inside an array in Excel VBA. The first method is used when the developer wants to hardcode it themselves. The second approach allows the user to enter the data.
CASE WHEN statements are similar to if-then statements in other programming languages. These statements are used to have SQL execute certain behaviors as determine by the criteria that is set in the statement. In the video below, we will go through several examples of how to use CASE WHEN statements in SQL.
For many students, working in groups can be a serious challenge. Different people have different temperaments regarding communication, work style, and ability to cooperate. It can be difficult to have success when a student is compelled to work in groups.This post will provide three tips for improving the group work experience of students.
Example Projects
Perhaps one of the best ways to get students going when it comes to completing group work is to show them how other students have dealt with this problem/project in the past through showing examples. When students see examples, it helps them process what is possible and what the expectations are for earning a certain grade.
Often the struggle with groups is trying to determine what to do. This is usually the first impediment to the project. Examples of prior work help a group determine which ideas they have are reasonable as they try to pivot off what the teacher has shown them as potential projects.
Checkpoints & Communication
It is often common for teachers to assign the entire project and only collect or comment on the final submitted project. This is a high-stakes approach that can lead to frustration when cooperation is not happening for many people working in groups. This is one reason why many students want to work alone to control everything.
A better approach is to break the project into pieces and provide feedback and support at each checkpoint. Students are provided with an opportunity to check in with the teacher as a group and feedback before the final submission. In addition, this also allows the teacher to communicate with students about expectations and address any problems that may have arisen proactively. Sometimes, students will just suffer in their group until the last minute. However, the teacher can guide the group towards success rather than failure and frustration by breaking the project into smaller pieces with frequent feedback and communication.
Separate Grading
Freeloading is a common problem in group projects. There are always students who believe in doing minimum and even nothing when working in a group. This practice may be one of the main reasons students dislike group work. The project often becomes a solo project in which the smart student does everything. One way to deal with this problem is through separate grading.
Instead of giving one grade that is exactly the same for all members, a teacher can give separate grades based on the contribution of individual members. Often, two grades are provided, one for the entire group project and a second grade for the individual contribution. Doing this makes group members individually accountable for their part.
HOw the individual grade is calculated can vary. Some teachers lick to have peer evaluations as part of the final grade in which members of a group evaluate each other’s contributions. This works in cultures that accept conflict more. However, in more collectivist settings, students will often mark everyone high to maintain harmony even if there is evidence that many did not contribute.
Another approach involves the teacher marking the specific contribution of the individual members. However, there must be some sort of rubric for this to work. Essentially, every group must follow the same process for the teacher to mark them similarly. In other words, the group project becomes a collection of individual assignments that are lumped together as a project. Doing this would limit the flexibility of each group with the tradeoff of higher accountability.
Conclusion
Groupwork has a place in the classroom. It allows students to develop communication skills, compromise, and work in less-than-ideal situations. However, the teachers must find ways to help students succeed in the context of group work so that everyone can perform.