Exploring Heat Transfer

Setting up the activity for this week’s application required various techniques in order to obtain reliable data. The activity’s procedure is to obtain 4 mugs and pour hot water into each one, then select various materials to cover the mugs and after thirty minutes check the temperature and see which material makes the best insulator. The first step was to achieve the following constants (variable

s): 1) 4 identical mugs made out of glass, 2) mark each mug at the same measurement as to have the same amount of hot water poured in each mug, and 3) maintain the temperature of the hot water in all 4 mugs at the same degree before covering with the selected materials. I had to obtain a more reliable thermometer than the one provided in the science kit. Finally, I selected the 4 materials I would use to cover each mug: aluminum foil, ceramic, glass, and plastic.

First inquiry question would be: what material will make the best insulator? After adding the hot water into the 4 mugs, I quickly covered each mug with on of the selected materials and waited thirty minutes to read the temperature of the water. My hypothesis based on prior knowledge would be that the aluminum foil would maintain the heat better than the others. I personally use stainless steel mugs to carry my hot coffee on my way to work. I relate the stainless steel mug to the aluminum foil cover I will put around one of the mugs. I believe as stainless steel makes excellent insulators, aluminum will also do the same being a metal.

After thirty minutes, the temperature of the hot water was higher in the mug covered with aluminum foil, then followed the mug with the hard plastic cover, then the one with the glass cover, and finally the one with the least heat retention was the mug with the ceramic cover. Aluminum foil proved to be the best insulator as expected
When aluminum foil was rapped around the mug, pockets of air were trapped. It is proven that trapped air acts as an insulator against conduction and convection (Tillery, Enger, & Ross, 2008). This is one reason it was a good insulator, but the main reason is that aluminum reduces heat transfer produced by radiation and reflects the radiation back into the hot water. Thermal radiation is reflected rather than absorbed. Remembering always that aluminum foil is also a heat energy conductor. This could set the stage for inquiry questions like the following: if all the covered mugs had air trapped in them, why was the aluminum foil the best insulator? or what properties of the aluminum foil help it be the best insulator among these selected materials?
References:
Tillery, B. W., Enger, E. D., & Ross, F. C. (2008). Integrated science (4th ed.). New York: McGraw-Hill.

Electromagnetism: Planning a Guided Inquiry

With the science kit provided I will be able to construct several electromagnetic models, which should produce electric and magnetic fields by applying electricity though a conductor. I will use the following materials: 1) 2 different sizes of common nails, 2) 2 different gauges of magnetic wire, 3) one battery C and one D, and 4) a few dozens of paper clips. The designing process can go hand in hand with the engineering standards for STEM implementation. Students will design the electromagnet from the given materials and make inferences about what would happen if the independent variables were to be changed. I have learned through experience that I should always do the experiment first before involving my students. I will use 2 of the 4 nails provided (iron 10-D and 20-D common nails). And with each trial I will use two different sources to provide the electric currents (C and D batteries). This would demonstrate what would happen if the electric current is increase with the same setup.

I proceeded to work first with the 20-D nail. I wrapped the copper wire around the nail 10 times. The coil formed was tight around the nail. I connected both lose ends to a C-battery and proceeded to check its electromagnetism by applying the tip of the nail to paper clips. Paper clips were attracted. I was able to pick up from 2-3 clips. Then I switch to the D-battery and applied it again over several paper clips, this time I was able to lift greater than 4 paper clips. This demonstrated that increasing the voltage would increase the magnetic field of the nail.

Then I wrapped the same nail twenty times with the copper wire. I connected the ends of the copper wire to the C-battery and applied the tip of the nail to the paper clips. I was able to lift 5 to 6 clips. When I switched to the D-battery the difference was very notable, over 7 clips. These observations supports the following conclusions: 1) magnetic field increases with increase voltage or electricity, 2) increasing the amount of lopes and creating a larger coil will also increase magnetic fields, and 3) the tighter the coil formed by the copper wire around the nail, the greater the magnetic field. Increasing the numbers of loops forms a cylindrical coil known as solenoid. When electrical current is passed through the solenoid, a magnetic field is formed. Its is a known fact that increasing the numbers of loops and the electric current will increase the strength of the magnetic field (Tillery, Enger, & Ross, 2008).

This is a very exciting and engaging activity for students to be able to relate electromagnetism with the different possible variables that can make the magnetic field stronger. In 1821, Michael Faraday set up a similar experiment to the one I will give as task (mini-lab) to my students when presenting the lessons on electricity and magnetism. Faraday did many different similar experiments that can be repeated easily in a lab (Bradley, 1991).

Focus questions like the following can be used to conduct this guided – inquiry lesson: 1) what effects does larger nails have on this experiment? 2) what effects on the created magnetic field would increasing the thickness of the copper wire have? This activity conducted as a guided inquiry can be very interesting and rewarding for my students. Students will engage in a set of activities that will generate data and provide them with information (Hammerman, 2006).

References
Bradley, J. (1991). Repeating the electromagnetic experiments of Michael Faraday. Physic
Education, 26, 284-289. Retrieved fromhttp://www.uvm.edu/~mfuris/faraday's_experiments.pdf
Hammerman, E. L. (2006). Becoming a better science teacher: 8 steps to high quality
instruction and student achievement. Thousand Oaks, CA: Sage Publications.
Tillery, B. W., Enger, E. D., & Ross, F. C. (2008). Integrated science (4th ed.). New York: McGraw-Hill.

How does the steepness of a slope and the mass affect a collision outcome?

I did the activity first before I actually do it in class. I have designed this as a guided inquiry activity. Providing my students with a step-by-step explanation, they will explore the concept of the model being used and compare it with real size models (Laureate Education, Inc., 2011).

The first step is to set up a straight-line track that can be flexible as to increase the gradient (slope). As the steepness of the slope increases, so does the gradient. To produce this track I used a piece of cardboard approximately 4 feet long. At this step, students will have to design their track using several provided materials. Students should interact with their group and brainstorm on how to obtain the best possible track to complete this activity. Also, this can be aligned with the engineering design process in which students will select the most promising idea and then create it (Teach Engineering, 2012).

Once the teams produce all the different tracks, the weight of the vehicle should be obtained. I would provide a set of 2 different rocks per team with known weights. Students will incorporate several different gradients for their slopes. For each gradient (at least two should be selected), students will release the vehicle 3 different times: 1) the vehicle without any additional weight, 2) the vehicle with one rock in it, and 3) the vehicle with both rocks. They should record all data and make their conclusions on the effects of steepness and mass on momentum and velocity.

My collected data and observations indicate that the momentum and velocity of the vehicle within the same slope gradient increases with added weight. As the gradient of the slope (steepness) increases, so does the momentum and velocity in comparison with lower steepness and same weight. Greater momentum will definitely increase the impact force on collision with an object or in real life with another vehicle. The length of the contact time during collision will determine the force of impact and the degree of damages or injuries.

When conducting this activity with my class, along with guidance and explanation I will constantly ask them questions and make sure they are engaged in an authentic problem solving process. As a facilitator I should be listening to their interpretations and help them correct any misleading information. I should also design questions that will help them connect this activity to real live experiences (Hammerman, 2006).

References:

Hammerman, E. L. (2006). Becoming a better science teacher: 8 steps to high quality instruction and student achievement. Thousand Oaks, CA: Sage Publications

Laureate Education, Inc. (Producer). (2011). Guided inquiry: classroom demonstration [Video webcast]. Retrieved fromhttp://www.courseurl.com

Teach Engineering. (2012). Engineering design process. Retrieved from
http://www.teachengineering.org/engrdesignprocess.php