heat transfer

Heat transfer experiment
This week in my physical science graduate class, heat and temperature were studied. Thus this week’s blog will discuss the experiment that I performed, what other materials that I could test for heat insulation and how I could change this activity to make it more interesting for my students.
I began this experiment by gathering my supplies. I used four identical mugs, a thermometer, four rubber bands, a measuring cup, and four materials to test. The four materials that I chose to test were aluminum foil, plastic wrap, a paper towel and cotton gauze. I expected the cotton gauze to allow the most heat to escape since it has holes in it and the aluminum to hold the heat the best.
Once my supplies were gathered, I took the temperature of my hot tap water. I then measured one half cup of water into each mug. Next I covered each of the four mugs with a material and set my timer for thirty minutes. When the timer went off, I took the temperature of the water and found that the aluminum foil and plastic wrap insulated the temperature the best.
If I was to perform this experiment again, I would like to test out rubber, foam and wool. I would expect the wool and the foam to insulate the best because they are porous and the book states that good insulators have small air spaces which limits the conduction through motion(Tillery, Enger & Ross, 2008)..
If I did this experiment for my students, I would make it relevant to them by making it about food. I would have the students test types of materials to determine which material would keep their hot chocolate the hottest or their soda the coldest.

References
Tillery, B. W., Enger, E. D., & Ross, F. C. (2008). Integrated science (4th ed.). 39. New York:
McGraw-Hill.

Momentum

This week I performed a guided inquiry activity for the question "Which pendulum will come to rest more quickly—a lighter pendulum or heavier pendulum?" My materials were three different sized washers, one nylon string measuring one meter long, a dowel rod, a stopwatch and a meter stick. After considering how mass affects momentum and researching about pendulums, I hypothesized that the washer with the smaller mass would come to rest more quickly than the washer with the largest mass.

Next I wrote the following procedure. Tie one end of the nylon string to a washer and the other end to a dowel rod. Measure the length of string between the rod and washer. Hold the dowel rod horizontally and pull the washer to a 45 degree angle. Let go of the washer and time the amount of time until the washer comes to rest. Complete three trials with each washer. Test all three washers using the same length of string and angle of release.

After conducting the inquiry activity, I found that each washer came to rest at an average of 28 seconds, so I concluded that mass does not affect the period of vibration (Communications, n.d.). Although these are not the results that I expected, the proof was in the inquiry.

If I was to perform this inquiry again I would change one of the controls like the length of string and redo the experiment to see if the results are the same even if the string was longer or shorter. I would also do more than three trials to get a more exact average.

In my classroom, I could set up this exact experiment allowing the students to select the bob(weight) for their pendulum and have the students graph their results(Communications, n.d.). The graphs could then be compiled to look for a best fit line. To make this activity more interesting and relevant, I could take the students down to the elementary school playground and use the swings as the pendulum and different students as the bobs.

I would like the students to learn that mass does not affect the period of vibration for a pendulum which coincides with what Galileo concluded about mass not affecting how long it takes an object to free fall to the ground when dropped (Tillery, Enger, & Ross, 2008).

Communications. (n.d.). Howstuffworks "Pendulum". Howstuffworks "Science". Retrieved May 16, 2010, from http://science.howstuffworks.com/pendulum-info.htm/printable

Tillery, B. W., Enger, E. D., & Ross, F. C. (2008). Integrated science (4th ed.). New York: McGraw-Hill.

new physical science grad class

I have started a new grad class at Walden called Exploring the Physical World. I will be updating soon with blogs about this new class.