21st Century Science

The 'big idea' I feel that is important for student's to understand is actually a topic we covered quite in depth throughout this course.  I feel it is important for student's to understand the difference between Newton's three laws, and it is important for student's to understand what these three laws explain.  Student's need to understand the concepts of motion, acceleration, gravity, force, etc.  These are all physical science aspects that student's encounter everyday so it would be very beneficial if student's could learn and apply this knowledge to the real-world.

I found a few sites that I feel are very user friendly, and that would benefit my students if they interacted with the site.  These sites are http://teachertech.rice.edu/Participants/louviere/Newton/ and http://www.physics4kids.com/files/motion_laws.html.  Both sites are easy to interact with, and student's can take short quizzes to see how well they are understanding Newton's three laws of motion.

Heat Transfer

Exploring Heat Transfer

            The purpose of the experiment this week was to investigate what materials would make the best 

insulators.  I chose the four materials I wanted to test, and carried out the experiment as instructed.  There

 were two things that I really focused on throughout this experiment: the four materials and how well 

they worked as an insulator, and why I thought each material worked as it did.

The goal for this experiment was to determine which of the four materials would work best as an insulator.  The four materials I chose are as follows: a dish towel, saran wrap, aluminum foil, and a paper towel.  Each material was placed over identical ceramic coffee mugs, each filled with one cup of hot water.  After the water was poured into the coffee mugs, I secured each insulating material over the top of the coffee mug with a rubber band for thirty minutes.  I hypothesized that the aluminum foil would be the best insulator, and the paper towel would be the inferior insulator.  I was unsure how the saran wrap and dish towel would work as insulators.  After the thirty minutes passed, I placed a thermometer in each coffee mug to see what the temperature was and to see how well each material performed as an insulator.  The temperature readings I recorded were: aluminum foil- 40 degrees Celsius, paper towel- 34 degrees Celsius, dish towel- 38 degrees Celsius, and saran wrap- 38 degrees Celsius.  Even though my hypothesis was correct, I was quite surprised with the results of the saran wrap and aluminum foil.

Despite the fact that my hypothesis  was proven to be accurate, I was interested in focusing more on the results given by the saran wrap and the aluminum foil.  While I was doing the experiment, I could actually see what was happening in the mug covered with the saran wrap. Based on our readings this week, I noticed convection occurring inside the mug covered with the saran wrap.  According to the website www.wisc-online.com, “As a gas or liquid is heated, it warms, expands, and rises because it is less dense.  When the gas or liquid cools, it becomes denser and falls.  As the gas or liquid warms and rises, or cools and falls, it creates a convection current” (Laurie Jarvis, Heat Transfer, 2011).  Convection was evident when I heated the water, placed the water in the mug, and covered the mug with the saran wrap because I could see steam and evaporation collecting on the saran wrap.  After about twenty minutes passed, water droplets began to form (condensation) and drop back into the mug.  This process was described exactly by Jarvis in the above quote.  Basically the entire water cycle took place inside my little coffee mug. I expected the temperature of the water covered with the hand towel to be cooler than the water covered with the saran wrap.  My first instinct was that the steam and evaporation given off by the water would escape through the stitching gaps in the dish towel, but when I think back now I did have the dish towel doubled over.  The fact that there were actually two layers of towel over the mug makes the temperature reading more understandable.  There was also more proof that convection and evaporation was taking place inside each mug due to the fact that each insulator was moist at the end of the experiment, and I could also see water droplets on the aluminum foil.

In conclusion, this experiment allowed me to see what kinds of material make good insulators, and what kind of materials do not make good insulators.  It was nice to see that my hypothesis was proven to be correct, yet it was also exciting to discover the results of the saran wrap and dish towel as well.