Heat Transfer

For this inquiry activity I chose to use four materials I thought would insulate, but in varying degrees. One of the difficulties was finding items that could be rubber banded to the mugs to keep the variables consistent. I went with four materials that fit together in pairs. Two were food related, foil and plastic wrap. The next two items were clothing materials, one cotton, the other an exercise material made from polyester. Because the clothing pieces had extra fabric hanging over the side, I carried the material of the other items over the side to keep it as consistent as possible. I chose these items in the hope I could make practical conclusions for the future.

The results were as follows (least to greatest temperature): plastic, cotton, polyester, and then foil. I was somewhat surprised because the foil easily won as the best insulator. Aluminum has a fairly low specific heat and the foil also has no gaps for air pockets. The only thing I can think of is that the aluminum had a higher specific heat than the other materials. I would have liked to have had the time to conduct multiple trials with other materials to see if I continued to get the same results. I did do two trials with foil winning, but one was only “finger” tested because I was having trouble with the thermometer. My thermometer from the science kit was broken, therefore, I was using a digital thermometer. I boiled water to disinfect baby bottles and then used the water from that when I was finished. Some of the cups were too hot to register so I poured them all together, mixed them and reset the experiment at a lower beginning temperature. The plastic did not register in the second experiment because it was too low, but I was able to get data from the others. The cotton and polyester were only one tenth of a degree apart, but the foil was just over two degrees warmer than both of them.

The idea of heat transfer at the molecular level can seem advanced for elementary students, but I think this is the "big idea" I would want them to be introduced to.  They are familiar with vibrations and the book did a nice job of comparing heat transfer from conduction in this manner.  I do not think I would have been able to take this away from this experiment without reading and researching further.  This would be something that would have to be taught by the teacher.

Guided Inquiry-Pendulums

The question I answered was: Which will come to rest first; a light pendulum or a heavier pendulum.  I set up the experiment using a regular golf ball and a practice golf ball.  I used a string to create a pendulum from my deck railing and released the ball from my hip each time.  I believed the heavier pendulum would come to rest after the lighter pendulum.  After conducting the experiment I found this to be true and made the conclusion that the heavier golf ball had more momentum, therefore making a larger arc and continuing to swing for a longer period of time.  The greater momentum is due to the formula Mo=Mass x Velocity.  The velocity would be equal, but the momentum on the upswing would be greater with the golf ball having the greater mass. 

An extension to this activity I would like to try would look at air resistance.  I would add more surface area to the heavier golf ball to see how it would impact the results.  If students had the prerequisite skills of accessing background knowledge, hypothesizing, designing an experiment, identifying variables, and drawing conclusions, I would use this as a guided inquiry lesson in the classroom.  If they did not have these skills, I would use it to model and do a think aloud to show students how I process an experiment.  Because the data is easy to collect and understand, this could be a great lesson to practice drawing conclusions from evidence.  To connect it to the students' lives, I would look for real life pendulums the students could relate to, such as a swing set.

In this lesson I would want the students to grasp the concept of momentum being Mass x Velocity.  I would also want them to become more familiar with the steps of inquiry.  Conducting this lesson as a guided inquiry would help meet both of these learning targets.