Exploring Heat Transfer

To explore heat transfer and determine the best insulator, I filled 4 ceramic mugs with 6 ounces of hot water, which was 192 degrees.  I chose 4 different materials to cover each cup: foil, cotton cloth, paper towel and plastic bag.  I then waited thirty minutes and measured the temperature of the water again.  I predicted the foil would be a better insulator of heat because if I wrapped my cooked food in aluminum foil, the food will stay warm.

I found the cotton cloth was a better insulator of heat because after thirty minutes, the cup covered by he cotton cloth had the highest temperature.  The hot water in the cup covered with cotton cloth retained heat longer.  After thirty minutes, the cup covered in cotton cloth was 120 degrees, the cup covered in foil was 118 degrees.  The cup covered in paper towel was 112 degrees, and the cup covered in the plastic bag was 114 degrees.  I was surprised the cotton cloth was a better insulator of heat.  I guess it would make sense because there is a lot of air between the knitted material.  When I am cold, I usually put on clothes to keep warm, which is mostly made of cotton.

I would like to test different materials to see which ones would be better insulators.  I would like to test other fabrics like nylon, polyester, denim, corduroy, and wool.  I believe the best insulator of these materials would probably be wool.  I think wool is a better insulator because it is similar to cotton cloth is that it has air between the knitted material.  I also know that when I wear wool sweaters in the winter, I get overheated quickly.

Marble Momentum

This week, I chose to investigate the question "How do different surfaces affect the momentum of marbles?  In the investigation, I used a 1-inch binder as a slope, two different marbles, a meter stick, and a stopwatch.  I chose two different surfaces: carpet and linoleum.  On the carpet, I timed how far the marble traveled in one second.  I repeated this three times.  Since I believe the marble will travel faster and farther on the linoleum, I decided to make a mark on the floor at one meter and time how fast it took the marble to travel that distance.  I repeated this three times as well.

I found the small marble traveled an average of 8.3 inches per second on the carpet.  The larger marble traveled 10.6 inches per second.  On the linoleum, the small marble traveled 16.46 inches per second and the larger marble traveled 15.26 inches per second.  The results were the carpet slowed the momentum of the marble because of friction.  The marbles had more momentum on the linoleum because there is less friction.  These were the results I expected.

This activity was not without challenges.  At the beginning of the investigation, I knew that I would measure from the bottom of the binder, but I was not sure how to incorporate the time.  I had a difficulty relating the collected data back to the focus question of the investigation.  I did not have a scale, therefore I was not able to weigh the marbles.  I know that the mass of the marble is a factor in measuring the momentum.

If I were to do this investigation in the classroom, I would have three groups test on the carpet and three groups test on the tile or linoleum.  I would discuss momentum before the investigation and be sure each group knows  how to calculate.  In order to make this more interesting, I would create a scenario or a real-world problem for students to solve.  I would want my students to have a good understanding of momentum, know how to calculate it.  Initially, I would like for them to find the momentum of one size marble.  When they analyze the results, then the next step would be to test a different size marble, or another object to test.  This would be our next question to investigate.