Wednesday, September 26, 2012

Sequence of Science Courses

DepEd's K to 12 employs the spiral curriculum in teaching sciences in high school. For example, in grade 8, the first quarter is assigned to chemistry topics which include the particle nature of matter, atomic structure, and the periodic table. The second quarter is mostly biology dealing with a wide spectrum of topics; the digestive system, cell division, biodiversity, and ecosystems. Physics is studied during the third quarter and in this year, the areas discussed are the laws of motion, work, power, and the different forms of energy. The fourth quarter is on earth sciences which include earthquakes, typhoons and the solar system. Looking back at Grade 7, one may then evaluate what the sequence of topics is and ask whether the various disciplines maybe influencing each other. In chemistry, Grade 7 talks about solutions, acids and bases, elements and compounds, and metals and nonmetals. Biology in Grade 7 seems to prepare students for Grade 8 biology as it covers parts and functions, heredity, and interactions within an ecosystem. Physics likewise as it introduces force, motion and energy. And the last quarter deals with the climate in the Philippines, the atmosphere, and eclipses.

Whether there are cross-disciplinary benefits is an important question. This in fact is an active research area for education in the United States. In this light, the sequence may be relevant. The spiral curriculum could be regarded as an extreme design of mixing the sciences. Cross-disciplinary benefits are more likely to happen when a student covers one branch of science for an entire year. The spiral curriculum can only devote one quarter of a year to each branch, so the topics student will be exposed per year in each branch of science are severely limited. The following in a study that describes how chemistry, for example, may aid in learning biology. This is an abstract of an Honors Thesis submitted by Lauren Kronthal to the Department of Chemistry at Georgetown University in 2012:

A Background in Chemistry Helps Students
Learn and Understand Biology
Lauren J. Kronthal
Thesis Advisors:  Sarah Stoll, Ph.D. and Gina Wimp, Ph.D.
         With the booming science, technology, engineering, and math job market, the United States cannot afford to be behind in the sciences if it is to remain economically competitive with other industrialized nations. High schools are desperately trying to improve their students’ understanding of the sciences by switching the order of science classes based on the suggestions of educational researchers. Recently, educators have proposed that chemistry be taught before biology since chemistry is necessary to fully understand biological concepts, but no empirical studies have been performed to show that chemistry improves student understanding of biology. I, therefore, addressed the question: Does a background in chemistry help students understand biological concepts?
            To address this question, I taught different biological concepts by 1) providing the relevant chemistry background or 2) not providing such background. I gave an assessment with questions of varying difficulty levels for topics where a chemistry background was provided/not provided and graded student responses. I found that a background in chemistry significantly improved students’ scores on questions that tested basic recall of information and on questions that required students to create a new idea using their knowledge of the content. Other levels of questions had no difference in mean class scores between when chemistry was taught and when it was not taught. Overall, students performed significantly better when given a background in chemistry. These results show that teaching chemistry before biology in high school can help improve student understanding of biological concepts.

To understand what the above study is really about, it is important to look at exactly what topics were being taught in chemistry and biology. The chemistry lectures are on intermolecular forces, polar and nonpolar compounds, and solutions, while the topics covered in biology are the sugars; monosaccharides, disaccharides and polysaccharides, as well, as movement of ions and water inside cells. In this case, the biology topics clearly benefit from a background in chemistry. Chemistry provides a perspective that allows students to see the components inside a cell in molecular terms. What is important in this curriculum design is a deliberate effort to connect the topics between the two fields of science. Such is not evident in the DepEd's K to 12 science curriculum.

The biggest disadvantage of a spiral curriculum is the lack opportunity to cover a variety of topics within one discipline in a year. Each discipline requires steps. To get to intermolecular forces and a molecular understanding of solutions, there are prerequisites. The topics build on top of each other and a quarter is simply not enough time to cover enough to aid the student in another field. It is simply the nature of the subject. Thus, designing a curriculum that will achieve what is described above will require a year of chemistry before taking biology.

Whether taking one subject in science helps in another is an important question. A survey of how students perform in college science courses provides preliminary insights:

Figure downloaded from 
The above does not directly answer the question since this is a study of how students performed in these fields after finishing high school. However, although it does not specifically address how a student's background affects a student's performance on a science subject in high school, it clearly shows that there are cross-subject benefits. Of special interest, is how high school math influences a student's performance in all sciences, including biology. The fact that students who had high school calculus perform much better across the board is probably not so much on an improvement in background, but more on being exposed to greater challenges. These studies are still ongoing and these illustrate how reforms in science education should be made. Reforms in science education can not be simply dictated in a whimsical fashion.  

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