Sunday, March 13, 2011

Spiraling Curriculum- Explorations of Density

Learning, does not grow out of rigid, systematically and carefully planned experiences. Learning occurs from an experience that is natural, unexpected, expansive, and encourages open-ended investigations. Teachers can not always determine how an experiment is going to run, or how effective it will be. Students often take unexpected directions from the planned experiment that provide numerous opportunities to further their knowledge and understanding, or prepare the students for learning that science concept in the future. For example, Ms. Drescher's class took the concept of observing that all the different liquids had different weights causing them to disperse differently when mixed together and expanded it to include volume. When the students noticed that changing the volume did not affect how the liquids dispersed when they were mixed together, Ms. Drescher needed to then explain the concept of density the children had stumbled upon. All experiences students have with science are only preparing them and laying the framework to build upon with more challenging and complex science concepts in the older grades. With more vaired experiences in the early grades, students will be richer in prior knowledge and preparation that they can utilize in the older grades. Therefore, I feel that schools that demand exact adherence to a specified curriculum are missing out on the opportunity to further students' science experiences and prior knowledge to include a greater variety and quality. When a student tries to extend the lesson further or in a different direction, teachers in these types of schools will direct the student back on the very clear, outlined, and safe path they are expected to take. There are no risks involved, and without taking risks, I believe true learning will not occurr.

Density is mathematically defined as the mass of an object divided by its volume. It is expressed numerically in grams per cubic centimeter, and explains how tightly particles are packed together in a given amount of space. Even though a subject's mass or volume may vary, its density remains constant. Objects that sink have a greater density than the substance the object is in, which therefore, causes the obejct to sink. Objects that sink in water displace water, and the volume of the water displaced is equal to the volume of the object. An object that floats has a density that is less than the substance it is in, causing it to float. An object that floats in water it is supported by a buoyant force, and displaces water. This means the mass of the water displaced is equal to the mass of the object. For example, objects with a density greater than 1 gram per cubic centimeter will sink and those with a density less than that will float.

In the science story about the students observing how the egg sank in tap water, yet floated when salt was added to the tap water (demonstrating that since more particles were added to the water it became more dense than the egg) were able to visualize the concept of density. Comparing this to real-life experiences, such as being in the ocean, students can apply this to the Dead Sea. The Dead Sea is many times saltier than any other ocean, and perhaps the students may be curious as to why it is many times saltier than any other ocean. Other questions that may arise could include: how do objects that float in the Atlantic Ocean compare to objects that float in the Dead Sea, is the Dead Sea too salty to support life, will objects float more in the Dead Sea than in the Atlantic Ocean or other oceans, etc. In an experiment, students can prepare by researching information about the Dead Sea on the Internet first, and then by performing an experiment. Students could simulate their own Dead Sea and other comparable ocean. By first researching, they could find out how much salt is in the dead sea by volume, and how much salt is in another ocean by volume, create a ratio to a more reasonable volume to use in the classroom, and find out how much salt would be needed to simulate the two bodies of water. The salt would be the changing variable, while all other variables would be controlled (volume of water, objects). Then, the students could use the same objects in each of their bodies of water, compare how much they float or sink, take measurements if possible to see how much the water was displaced, and conclude based on the collected results.

A spiraling curriculum is one where science curricula and topics are further expanded upon with each increasing grade. Students build upon previous knowledge of science topics year after year, developing a greater depth of understanding. From my personal experiences, I know I have and still benefit from this structure of a spiraling curriculum. I always had difficulty in math as a younger student in grade school. Each year, I would look forward to being able to forget everything I learned last year and think that I would never have to face those challenging word problems, for example, ever again. However, each year I would consistently be provded wrong, as we would begin the school year by reviewing concepts learned the year prior, and then spend the remainder of the school year expanding upon these foundational concepts. This pattern, of course, was present and consistent throughout all subjects taught in school I believe that is wasn't until recently that I have grown to appreciate this way and structure of teaching. Although I am in college, my professors are still building upon concepts I recall learning or at least being exposed to in high school. These prior experiences with concepts better prepared me and enabled me to do well in both high school in college, as I had a foundation to build new knowledge off from. Without a starting block, I could imagine it begin very difficult to try and assimilate and accomodate new information into my memory. For example, the early introduced concept of photosynthesis (sun+water+CO2-->oxygen and sugar) has been expanded upon each year I have been in school. All of these prior experiences with photosynthesis well-prepared me for the culmination of this concept in college biology. A spiraling curriculum enables students to be able to look back in order to look ahead.

This website has a lot of great science activities for kids:

This activity, Tie Dye Milk, is a great surface tension experiment students love to do:

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