Ms. Science Teach: October 2011

In this week's assignment, I was challenged to find my "most powerful" websites, and I found several. Conservation of mass and energy is a big idea for most middle school students. So I decided to see what's out there. If one of my students wanted to gain a better understanding, what would they do? They would Google the topic.

The very first "hit" I got on the topic was from Wikipedia. This is a website I discourage with my students due to reliability issues. So I moved on. One great website I came across was http://www.neok12.com/Law-of-Conservation.htm. This site has wonderful short videos which are easy to understand. I viewed one on the law of conservation of energy using a bowling ball as part of a pendulum. The teacher gave a great demonstration for his students along with an explanation of what they were viewing.

Another great site I stumbled upon was http://www.learner.org/resources/series42.html. This site is great for both teachers and students. This is a video that shows physics in every day life such as: riding in a hot air balloon, listening to a symphony and even visiting a bicycle shop.

My classes contain a wide variety of learners. Some students are in my room just to be exposed to science. I found one website that I could use for my lower learners and also as an activity for early finishers. I came across an online game called "Reduce the Use". This was an online game which guides the user throughout a home with the task of finding ways to conserve energy.You can play the game at http://www.reducetheuse.ca/.

For further enrichment, I found a great website called "Science Geek". This site had all sorts of activities in chemistry. There are games for every topic including the conservation of matter. One game I could see myself using in my own classroom was "Balancing Chemical Equations". Here, students can practice their skills at balancing chemical equations. This activity is a great way for students to actually see the conservation of matter. The atoms add up.

Of all the sites I discovered, one did stand out and quickly became my favorite. Learningscience.org is a great website for middle school lessons on forces and motions. Each activity allows the user to manipulate variable and test outcomes. The lesson I found on conservation of energy allows students to manipulate a skateboarder's ramp. You can see an instant graph of the results. I liked the way it showed students how you could only get what you put in. In other words, the skateboarder will only return to a point slightly lower than his starting position. Students have three sections of the ramp they can manipulate to see how it effects the energy. The website is found at http://www.learningscience.org/psc2bmotionforces.htm.

The idea of the physics in music had my attention. I think it would be neat to bring in instruments of different varieties. I would set up a straw in a glass goblet. Then I would play each instrument and have students observe how much movement occurred with the straw. It may be a challenge to bring in the variety of instruments and play them successfully but I am up for it.

There are various materials used to keep both food and people warm. As a child, I knew that Styrofoam cups kept hot drinks hot. However, today I often wonder why many coffee shops use paper cups. Canadian scientist Martin Hocking showed in his research that manufacturing a paper cup uses as much petroleum or natural gas as the polystyrene cup (Eco Joe, 2008). I kept this in mind as I set up my experiment. My independent variable was the materials used. My constants include identical mugs and the starting temperature of the water. My dependent variable was the measured heat loss.

The Materials

For this experiment, I would need the following materials: four identical coffee mugs, hot water, measuring cup, four insulators, a timer, and a thermometer. My four insulators were cotton fabric, one paper towel, aluminum foil, and one sheet of copy paper. I chose these materials for two reasons. One, they were readily available in my home; and two, my curiosity see how they would compare.

Setting up the Experiment

I ran some water through my coffee pot and measured a cup of hot water in each mug. I covered each mug with one of the materials and secured with a rubber band. I set my timer for 30 minutes and waited. I completed one trial of my experiment. If I conducted this lab in the classroom, I would have my students conduct at least three trials to increase the validity of their data. I would then instruct students to take an average of the temperatures for each material used. Another observation for my students is to verify their knowledge of reading a thermometer.

My Results

The starting temperature of the hot water was 155 degrees Fahrenheit. I measured the temperature of each cup as I removed its insulation. The cup covered with a sheet of copy paper registered 94ºF, a drop of 61 degrees. The cup covered with aluminum foil registered 98ºF, a difference of 57 degrees. The cup covered with cotton fabric measured 105ºF, a difference of 50 degrees. Finally, the cup covered with the paper towel measured 97ºF, a difference of 58 degrees. To my surprise, the cotton fabric insulated the best. Most winter coats contain insulation to help trap heat in close to the body. Some manufacturers use a polyester fiberfill in their winter coats for that purpose (J. Smith & N. Pitts, 2011). Another surprise was how close the paper towel-covered water measured to the aluminum foil-covered water.

If I conducted this experiment again, I would conduct at least three trials and use more materials to test. I would like to test the materials but use them as a sleeve over the cup. Then, I would compare the results from the two separate experiments. This would help me determine whether the cup materials or if using a sleeve is better.

In using this experiment, I would encourage my students to research the cost of manufacturing the cups and find which insulation is not only the best in preventing heat loss but also the most economical. This would introduce cost-effectiveness to the students and help them gain insight into why companies choose one material over another.

This experiment did not present me with any significant challenges. Only one came to mind. It might be more accurate for students to test one material at a time as opposed to all four materials at the same time. One must consider the time it takes to secure each material on each mug. The time lost might possibly skew the results. Overall, the lab is a great way to illustrate heat loss and insulators. Students can discover how they work through a lab such as this.

DATA

Insulators and Temperature

Material Used (Insulator)	Starting Temperature of Water	Water Temperature (F) after 30 minutes	Water Temperature (C) after 30 minutes
Copy paper	155ºF/71ºC	94º	37º
Aluminum Foil	155ºF/71ºC	98º	41º
Cotton Fabric	155ºF/71ºC	105º	43º
Paper Towel	155ºF/71ºC	97º	39º