Heat Transfer

In this week’s “heat transfer” experiment I decided to work with four fairly common materials: aluminum foil, plastic wrap, newspaper, and cotton cloth (See picture below). The main reason I chose these materials is because they are all very common items, and their flexibility made it very easy to wrap around the mugs. When I decided on these items, the first material that stuck out in my mind as being the best insulator was the aluminum foil. It is often used to keep food warm and when used in extremely hot temperatures, foil often reflects the heat instead of absorb it. The plastic wrap seemed like a decent insulator except for the fact that it often melts at high temperatures. The two materials that seemed like they would be poor insulators were the newspaper and the cotton cloth. Both materials are very porous and allow heat to be released outside of the mug. Cloth being the most porous would likely be the poorest insulator of the bunch.

According to the results, my hypothesis was confirmed, although not in a very convincing fashion. The results only between the four materials only yielded a total difference of 2 degrees Celsius. If I were to set up this experiment in the classroom, I would definitely use laboratory apparatus, such as test tubes and glass thermometers. The tubes would allow for smaller pieces of material to be utilized and a much more secure seal around the mouth of the apparatus. The glass thermometers would allow for an increase of initial water temperature, which I believe would result in much more convincing differences in the data.

To make things more exciting for the students, I would have them bring in cups and lids from various coffee houses and tea shops, and have them test the quality of insulation from each vendor.

Due to the fact that some of the local coffee shops still serve their beverages in non-biodegradable styrofoam cups, students can show how much more effective or less effective each cup is.

They can also put together a report that shows how the use of these Styrofoam cups affect the nature of the business, and if the cost savings and quality are worth the negative environmental impact the material possess.

Another idea is to compare the differences between different fast food burger joints and how they serve their food to go. On several occasions I have ordered food through a fast food drive-thru just to open up the container at home to find a luke warm cheeseburger and soggy fries. Which materials make for the best insulators?

Several restaurants (fast food and sit in) have moved away from serving their food in styrofoam containers and instead have utilized foil, paper, and cardboard in an effort to be environmentally conscious.

I am sure there are several other ways to get students more engaged in an investigation involving heat transfer. Although I believe if they can get involved in a movement to make this world a better place, some of their passions can flow into the work that they are doing. There is nothing more uplifting as an educator than observing our student’s passion in the work that we assign.

Guided Inquiry Lesson Reflection

This week I participated in a guided inquiry lesson attempting to answer the question: How does the steepness and mass affect the outcome of a collision?

I initially set up the experiment by setting up a ramp with three different incline gradients as shown in the pictures. Using the same marble, I proceeded to roll the marble down the ramp and observed and recorded the distance the toy car traveled from its original position. As you might have expected, the steeper incline produced the furthest results and the more gradual incline produced the least amount of distance. This is due to the combination of the momentum formula and Newton’s second law of motion.

The second experiment set up is pictured below, with only the steepest ramp used. Instead of using the different gradients, I used a smaller marble with less mass. As expected the marble with less mass produced the least amount of momentum transfer and the more massive marble produced a larger transfer of force resulting in a distance twice a far as the light marble.

If I were to modify the result to provide more evidence for Newton’s second law, I would use a different vehicle, some more massive and some less massive to show that a greater force is needed to move an object with more mass. I would also experiment with the types of surfaces used to roll down the marble to enhance the lesson to include friction. Since this experiment can potentially have so many variables one of the challenges would be to try and reduce the amount of variables a student or group of students will experiment with. Once multiple independent variables come into play, student results will become more inaccurate and less reproducible.

Having students come up with their own experiments using materials to suit their interests would make this activity more engaging. Skateboarders could use skateboards and ramps, while baseball players could experiment with friction on grass versus dirt, etc. This would allow students the freedom to create and invent their own procedures resulting in more variety of products.

Students can ultimately learn that science can produce similar results using different materials. One can prove Newton’s laws of motion in more than one way. These laws hold true regardless of the environment or circumstances a person or object is placed in. I believe students can gain the skills to provide evidence of the laws of motion in various ways and think creatively and critically about how to go about achieving that goal.