Heat Transfer

In the insulation experiment I was fascinated to see which types of common materials work the most effectively at preventing heat loss. As a person that likes to be efficient with energy usage I was most curious to see if there was a common household item to further help me become more energy efficient. In this experiment the materials tested included aluminum foil, plastic wrap, cardboard, and newspaper. From the experiment I found that my hypothesis of the aluminum foil being the best insulator was confirmed due to the high reflectivity of aluminum foil for thermal energy and the effective radiant barrier it develops against heat loss.






The most interesting result came from the cardboard which was the second best insulator. This is attributed to the multilayered weaved construction of the cardboard. The overlapping layers prevented easy heat loss through radiation while the overall construction of the cardboard created a pocket of air between the two layers of weaved paper. This allowed for the air, once heated, to act as a blanket and further seal the system. Thus, the cardboard utilized two strategies to insulate the mug, the layered thicker paper and the pocket of air in between the layers of paper. This strategy of utilizing air as an insulator is observed in nature as well. As we shiver the erector pili muscles under our skin stand up the hair on our bodies which in turn traps a layer of air under the hair. The radiant heat from our bodies heats the air and the air reradiates that heat back to us. Thus, the air acts like a blanket around us. 

The data gained from this experiment demonstrated for me that the most effective method of preventing heat loss is to employ multiple strategies in insulation. I was greatly impressed by the cardboard’s ability to insulate the mug. A simple thing like paper when teamed up with another insulator can be dramatically effective. For instance, the aluminum foil covered with cardboard would be an excellent adaptation to this experiment that may also decrease the heat loss. This information would lead to the further application of heat transfer through more effective strategies of insulating food and our homes. 

If I was to repeat this experiment I would try using two insulators in conjunction and try a variety of materials to see how the use of these insulators in tandem further improves their ability to prevent heat loss. For instance, cardboard wrapped in aluminum foil or plastic wrap topped with a hand towel. In the end I would expect the cardboard wrapped in aluminum foil to be the best insulator; however, the use of multiple insulators should increase their overall effectiveness.

Guided Inquiry Gains Momentum

For this experiment I selected one of several guiding questions about the concept of momentum. In the guided inquiry process students, like me, are given a choice among objective questions or concepts to explore. The students are then charged with developing a way to test their guiding question and find the supporting evidence for their solution to the question. For instance, “How do different surfaces affect the momentum of marbles?” was the guiding question that I chose to explore. To explore this question I designed some simple experiments to test to see if changing the surface that a marble rolled down would change the momentum of the marble. In designing the experiments I was also able to incorporate the engineering design process into the implementation of the inquiry lesson. There were several aspects of the experiments that I held constant including the degree of incline that the surface was at, the distance the marble traveled on the surface and the marble itself. Then with all of these factors held constant the only manipulated variable was the surface the marble rolled down. The surfaces that I chose were a piece of standard computer paper and a piece of carpeting. What I found from the experiment was that the marble had a higher momentum rolling down the piece of computer paper as compared to it rolling down the piece of carpet. It was evident that the marble rolled down the piece of computer paper at a higher velocity than it did roll down the piece of carpet. Since the momentum formula is the product of mass and velocity and if the mass is constant in both experiments the different velocities would indicate different momentums. An increase in the velocity of a constant mass would therefore increase the momentum of that object. Thus, the marble traveling at a higher velocity down the piece of paper would in turn have a higher momentum than the slower velocity demonstrated in the marble rolling down the piece of carpet. This also led me to the conclusion that an increase in an opposing frictional force of the surface decreases the velocity of the marble traveling down the surface and thus decreases the momentum of the marble. It also demonstrated for me that the roughness of a surface is directly proportional to the surface area of that surface. With an increased surface area the opposing frictional force also increased, further slowing the velocity of the marble and decreasing its momentum. As I completed this activity I immediately thought of sports and the application of momentum to a sport like ice hockey where the surface of the ice is vital to the play of the game. Through this guided inquiry experience I was able to develop the concepts of friction, surface area and the momentum formula that lead to the construction of a more complete conceptualization of how momentum is applied to real life.

The scientific inquiry experience allows the students, in this case me, to further develop a concept through discovery learning. The guided inquiry process allowed me to take the prior knowledge that I had on momentum and scaffold new concepts and application of momentum to what I had already known. Since I have a fairly good background in momentum, more than what I would expect for a sixth grader, the guided inquiry activity did not directly reveal a new aspect of momentum that I had not already known; however, it did expand my application of momentum to more real world applications. Through this process I was able to scaffold my knowledge of momentum into applications such as sports to further understand the physics used in much of the entertainment. I was also able to see firsthand how the inquiry design process and the engineering design process overlapped. The creation of a scientific procedure or process to solve a given problem unified the complementary instructional techniques. This process also allowed me to see how inquiry and the engineering design process are implemented on various levels and gave me the opportunity to be the “student” for the activity. The guided inquiry process challenges the students, even students that have a good background in a concept, to find new applications of the material.

In the process of guided inquiry there were only a few places where I felt like some support would have aided in its implementation. As a student in this process and as a facilitator, one stumbling block is usually in the design of a procedure that the students need to develop. Students, including me, usually have no trouble selecting a guiding question but stumble when it comes to designing an experiment. Often we want to jump right into the process without thinking it through for what variables we can change and what we need to keep constant. If this is not done properly the experiment can yield faulty data and thus complicate the concept further rather than reaching the intended goal of illuminating the concept. However, if the design for the procedure is well thought out and implemented, the inquiry process can be an extremely effective tool to develop a concept. This design can also demonstrate how the engineering design process can effectively be incorporated into an inquiry lesson so that students benefit from the differentiated approach of both instructional strategies. In inquiry students take an invested role in developing the material of the class. This leads to a deep sense of ownership of the material and thus leads to the development of extending thinking strategies for the application of the material. The real life application of the material is one of the hallmarks of inquiry and as such gives the students real world connections that develop the material into enduring knowledge.