Heat Transfer

This week I had to do an experiment to determine which materials would serve as a better insulator. The materials I chose to test were aluminum foil, a piece of sealing plastic wrap, a cotton wash cloth, and a piece of newspaper. To properly complete the experiment, the mugs and the amount of water had to remain constant. I used four of the same types of mugs with 1/2 cup of hot tap water in each cup. My hypothesis was that the plastic wrap would work best. I based my guess on the fact most of our drink covers are plastic and the inside of most coolers are plastic.

The initial temperature of the water was 100 degrees Fahrenheit. After 30 minutes, the temperatures were as follows: newspaper- 92 degrees Fahrenheit, aluminum foil- 94 degrees Fahrenheit, cling wrap- 95 degrees Fahrenheit, and the cotton wash cloth- 93 degrees Fahrenheit. According to these numbers, my hypothesis was correct. But looking at results from some of my colleagues, I'm starting to question my results. From what I've seen the plastic wrap has been coming in last place with some of my fellow classmates. There are couple of factors that may cause the differences. (1) The plastic wrap I used was a cling wrap. It's not like normal plastic wrap. (2) Maybe the wash clothes were different. Maybe mine was a little thinner. (3) There could also have been a human error in reading the thermometers.

Despite the differences, this was still a good experiment that I will use for my students. I may change it up a little bit. Instead of testing which materials make the best insulators for lids, I will probably have them investigate what type of cup will keep a hot beverage warm the longest. They could have several different types of cups (Styrofoam, glass, ceramic, plastic, etc...). Instead of using water, I may let them use hot chocolate. I think they'll appreciate that because it'll be cold by the time we cover heat transfer here in Georgia.

Guided Inquiry

This week I had to create an experiment to test how different surfaces affected a marbles momentum. To achieve my goal, I created a ramp that consisted of two books and a piece of cardboard. I also used the larger of the two marbles that was in our science resource kit. The two surfaces I used was the carpet and hardwood floors in my house. The fact that I had the different flooring in my home was very convenient.

My hypothesis was that the marble would travel further on the hardwood surface than on the carpet. I was correct! The marble rolled 66cm from the end of the ramp on the carpet and more than 4m on the hardwood. This was because the friction between the marble and carpet slowed the marble's momentum faster than the hardwood.

This was a good experiment because it was rigorous, but still simple enough to perform in the confines of my home. Thinking back, I should have tested both marbles on the surfaces and see if the different masses would have any affect on the outcome.

When I use this experiment for my students, I will give them 3-4 different balls, all with different masses. I will have them to create their own experiment to determine the affect different surfaces have on an objects momentum. One challenge I see with this in school is the fact that there is not much carpet in our school. To alleviate this problem, the students could go outside and use the concrete, grass, or the track surface.

Another issue I see is some of the students becoming intimidated by the rigor of the activity. More and more activities like this will enhance their critical thinking skills and allow them to be more competitive in the real world (Lantz, 2009).

References:

Lantz, H. B. (2009). What should be the function of a K–12 STEM education? SEEN Magazine, 11(3). Retrieved from:http://www.seenmagazine.us/Sections/ArticleDetail/tabid/79/ArticleID/208/smid/403/reftab/292/Default.aspx

Structured Inquiry Lesson

I choose to present a lesson to 3 eight graders that were helping us get our new school together. The lesson was on density. The students are to pour 20ml of Karo syrup, shampoo, dish soap, water, and cooking oil into a graduated cylinder, and determine which one has the highest density. In the past I've mixed the substances myself and let the kids see the results. After I read the resources, and witnessed other inquiry based lessons, I realize that was a mistake.

I took the lesson a little further. This time, I had the students determine the densities of each substance before they were mixed, and try to hypothesize what would happen when they were all mixed together. One good thing about this is that it allowed students to use math skills along with science. I also tied the lesson into real world events. I asked the students was it possible for oil in the Gulf to be suspended under the surface of the water? Once they poured all the liquids in the cylinder and saw that oil floated on water because it had a lower density, they were able to answer the question.

Melting Icebergs

The results from this weeks experiment was very surprising to me. I just knew that once the ice cubes melted, the cup would overflow. Boy was I wrong! The water level stayed the same. How could this be? After about 2 minutes of confusion, the answer finally hit me. The water level didn't change because of volume. The liquid produced by the melted ice still had the same volume as the solid ice cubes. The water didn't create any new space.

What will happen if the polar ice caps melt? I think this experiment proved part of the answer. If the ice caps are already floating in water, then we won't have to worry about any flooding or rise in sea level. On the other hand, if the ice caps are covering land, the newly produced water will cause flooding or a rise in sea level because it will add volume to the oceans.

Although global warming isn't a topic I cover in 8th grade Physical Science, I can use this lesson in the unit I teach volume. In addition, this lesson addresses a real life issue that could possibly affect everyone in the future.

The one major question I have is what will happen to the wild life (polar bears, etc...) that are living on the ice caps if they melt?

Move That Marble (App 2)

This weeks application was a little more involved than I had anticipated. The fact that my wife and I are on vacation in Florida made it even harder. I created a lesson called "Move That Marble." The lesson is designed to test the students' knowledge of simple machines. They were to create a model of a compound machine that consisted of 3 or more simple machines the would move a marble 50cm vertically and 100cm horizontally.

I normally don't use the five E's when designing my lessons. In addition, all five didn't apply to my lesson plan. For example "Exploration" calls for the teacher to facilitate and guide the instructional process. In this activity, the students create their own procedures and use whatever materials they can get their hands on. I think the Five E's are a good guide to lesson planning, but I also think the success depends on the type of lesson you are giving.

Hello everyone. I look forward to blogging with all of you. I'm new to blogging so hopefully I get the hang of it soon. Good luck to all of you with this course.