Sunday, January 30, 2011

Ivvestigating Heat Transfer

We often hear the word heat. Nevertheless, what is heat? Can I see it? Heat is the thermal energy that is transferred from one object to another when the objects are at different temperatures. Heat energy is transformed into thermal energy that flows from warmer to cooler objects. This process can occur in three ways conduction, convection, or radiation. In order to explore the concept of heat transfer it is important to understand the concepts of temperature such as insulation, convection, and conduction. This week's inquiry labs provides an opportunity to do a hands on activity to investigate heat transfer.
To begin I needed to pick four materials to test. My objective was to see if they were good insulators of heat. I selected aluminum foil, plastic, oven mitt, and small piece of foam.
My educated guess (hypothesis) was that the plastic, foam, and mitt would be the best insulators and the aluminum would lose heat much faster than the others would. Since aluminum foil is a metal it is consider to be a conductor not an insulator.
My next step was to set up the experiment. I used several ceramic coffee cups from my kitchen, the thermometer found in Walden’s science kit, a piece of aluminum foil, plastic wrap, a oven mitt, and a piece of foam cut from a foam cup. After setting up the lab, the next step was to perform the experiment. I read and followed experimental procedure as written. The four coffee cups were placed in a row on an even surface and each received three-fourths cups of hot water. After which I measured the temperature The temperatures varied a little for several of the cups. The cup I covered with plastic wrap and the mitt measure 36 degrees Celsius. The cup I covered with foil and foam measured 38 degrees. Once the temperatures were recorded the cups were securely cover with the preselected material (aluminum foil, foam, oven mitt, and plastic). I decided to observe the material in 15 min interval for a period of thirty minutes.
After the fifteen period ended, I removed each of the covers from the mugs. At the end of the fifteen minute interval the cup covered with the mitt and plastic wrap measured 32 degrees Celsius. The cups with the mitt and with the foil measured 30 degrees Celsius, and the cup with the foam measured 36 degrees Celsius. I recovered each cup for a additional 15 minutes. At the end of 15 minute interval a total of 30 minutes, the cups covered with plastic and mitt measured 28 degrees Celsius. The cup covered with foil measured 26 degrees Celsius. And the cup with the foam measured 34 degrees Celsius.
In conclusion the inquiry experience performed as expected. The cups with foam proved to be the best insulator. The cups with plastic and the mitt were about the same. The cup with the foil was the poorest insulator.
In addition, this lab would be a good hands-on activity for my students . There are several thing that I would change one is the amount of time provided between intervals. I would need to include addition question and discussion while the student wait to measure temperatures. Also, I notice that it was a little more difficult to measure temperature with only one thermometer. The lag time between measurements could affect the accuracy of the results. Also the lab could be expanded to allow student to investigate using a control cup. This way the students will be able to observe how heat transfer reacts with out insulators.

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

Sunday, January 16, 2011


 Guided Inquiry Lab Momentum
According to Tillery, Enger, & Ross, 2008, momentum is defined as the product of the mass of an object and its velocity. In order to investigate the concept of momentum I decided to investigate the question "How do different surfaces affect the momentum of marbles ?" Based on prior knowledge I understand the mass of an object can have an affect on the momentum of an object. The greater the mass and speed of an object, the greater its momentum and the greater its transfer of energy to another object In addition I understand that momentum is also reduced by gravity and friction . To start my guided inquiry lab I decided to test my marble on three different surfaces. I chose to test the marbles on indoor carpet, linoleum, and hardwood. I also decide to run three trials on each surfaces.

First off, I set up the inquiry lab using a large size marble, a pencil , and a yardstick. I shot the marble on a carpeted surface and measured the distance it traveled across the surface. I took the average of the three trails. The marble traveled an average of 200 meters on the indoor carpet.

Secondly, I tested the marble on a linoleum surface. Once again I did three trials. The marble traveled an average 230 meters on the linoleum surface. The marvel seem to travel at a faster velocity than on the carpet. On one of the trials the marvel seem to want to travel the full length of the floor.

Thirdly, I tested the marble on a wood surface. Again I repeated the process three times. The marble traveled an average of 433 meter. The distance double the carpet and linoleum surfaces.

In conclusion I observed the the marble traveled the furthest on the wood surface. Based on the data I would conclude that the wood surface offered less friction on the marble so it was able to travel further. I did have some difficulties with the lab. One thing that I notices is that on several the trails the marvel keep going until it ran into something. It was also hard to make sure that the same force was applied each time.

Finally, this guided inquiry lab help me to get a visual understanding how important friction is to stopping or slowing down an object. I also realized the importance of keeping good tires on an automobile. This lab could be used to follow-up with a lesson on set belt safety and automobile maintance. This lab can be modified by allowing student to do a follow up lab that investigate if the mass of the marble would affect how far it travels down a homemade ramp. This would help eliminate the issue I had with assuring that that the same force is applied each time. Also student would need to get a graphic organizer to help student record data with out having to struggle with deciding how many times to do a test.

Overall, providing guided inquiry lesson will helps students get more practice with inquiry labs it would also provide student the opportunity to investigate concepts that apply to real world issues. I can also use the practice of “I wonder” questions. (Banchi & Bell, 2008) to expand the lab and allow student to discuss and reflect on results and provide explanation.

References
Tillery, B. W., Enger, E. D., & Ross, F. C. (2008). Integrated science (4th ed.).
New York: MGraw-Hill.
Banchi, H., & Bell, R. (2008). The many levels of inquiry. Science & Children, 46(2), 26–29.