Potential and Kinetic Energy

Potential and Kinectic energy is an intersting topic for students to explore. This course we talked a lot about rollercoasters. Rollercoasters are something that most students can relate to since most of them have probably ridden them at amusment parks. This is an excellent way to connect students to the idea of potential and kinetic energy. The need to understand that when the roller coaster reaches the top of the hill it has potential energy and as it is going do the potential energy is converted into kinetic energy. There are a lot of fun websites that deal with designing rollercoasters with the topic of potential and kinetic energy. One can be found here http://www.jason.org/digital_library/4851.aspx. The students get to determine how many cars (3-8) they add and then design the track using hills and loops, but they coaster needs to hae enough energy to make it and stop at the end of the track without crashing. It shows the potential and kinetic energy as the coaster moves along the track. This could help students when they are designing their own coasters like the one we read about using the foam insulation and a ball.

Here are a few more sites that offer rollercoaster simulations some do not demonstrate potential and kinectic energy, but could be fun to play with and have the students explore various designs.
http://www.funderstanding.com/coaster
http://kids.discovery.com/games/rollercoasters/buildacoaster.html

Some interesting websites dealing with rollercoasters
this one has a demo video http://tlc.howstuffworks.com/family/roller-coaster3.htm
http://www.learner.org/interactives/parkphysics/coaster.html
http://www.teachersdomain.org/resource/phy03.sci.phys.mfe.zsplcar/
http://www.miamisci.org/af/sln/mummy/raceways.html

To help with the idea of potential and kinetic energy I would also show the BrainPop videos on both topics found here
http://www.brainpop.com/science/energy/potentialenergy/
http://www.brainpop.com/science/energy/kineticenergy/

What a better way to relate to a scientific topic than with something most students are familar with. After watching and working with some of these demonstrations it would directly into the Rollercoaster challenge.

Unusal Results- Insulator Experiment

     Materials that contain many small air spaces are generally good insulators because the air spaces are poor conductors since the molecules of air are far apart compared to that of a solid (Tillery, Enger, & Ross, 2008). We were tasked with testing different materials to find the best insulator. We were to use identical mugs, fill them with hot water and cover them with various materials to find the best insulator. The materials I chose to test were aluminum foil, paper towel, newspaper, and Saran wrap. Even though the experiment only called for four items I also used a piece of cardboard and a scarf. The scarf is made of acrylic. As a control I had a mug that was uncovered. I thought that the aluminum foil would be the best insulator.

All my mugs in a row

     To start of I figured out how much liquid the mugs could hold to be 12 oz, since I did not want to fill them to the top I decided I would fill them with 8 oz of water. In order to be able to heat enough water to fill all of the glasses I put some water in a pot and heated it on the stove. I then quickly measured the water and poured it into the containers and covered them with their corresponding materials. The major complication in this experiment was the thermometer. The thermometer that was in our kit only went up to 120ºF and the water was at a higher temperature than this. I ended up using my meat thermometer which went up to 220ºF. The increments were 2ºF so I sometimes estimated when it was in between two of the lines. It was also hard to read at times. The starting temperature of the water was 138ºF I waited 30 minutes and took my first reading. With all but the mug with the scarf and the one with no covering having the same temperature I decided to continue. When I took the temperature I lifted the covering just enough to allow the thermometer in so what heat was being trapped did not escape. I ended up taking four readings every half hour for a total of a two hour time frame. At the end of two hours I found that the Saran wrap (84ºF) insulated the best, followed by the cardboard (83ºF) and then aluminum foil, paper towel, and newspaper (82ºF) all tied. Had the scarf (86ºF) been under the same conditions it probably would have done the best since it did retain more heat than the Saran wrap.
     These results are not what I would have expected at all. First off when I placed the materials on top of the mugs I could feel heat coming through the paper towel, newspaper and the scarf some, but not through the aluminum foil, Saran wrap and cardboard. With this observation I would have thought that there would have been a bigger difference between the aluminum foil and the paper towel and newspaper. Some of my thoughts on the Saran wrap is since it is plastic, the water condensed on the top providing another protective layer. Also by keeping the water in the container it held onto heat since water does have a high specific heat. I think in the case of the newspaper and paper towel some of the water could have been evaporating through the materials since they were both moist to the touch. I did expect the scarf to do well since we use them to insulate ourselves. Some else to consider and the results is the material of the mugs I used. I used my Corelle Stoneware mugs, which even without any covering (78ºF) held the heat fairly well. I think the material of the mug used is also a huge factor. I would not expect to get the same results as someone that might have used paper or Styrofoam cups. It would be interesting to first test different materials to hold the liquid and find the best insulator without covering and then find the best insulator cover to support it.
     The main challenge I had was measuring the temperature. I wish I had a regular alcohol thermometer that might have been more reliable and given me better data. Or even having a digital thermometer might have been the most accurate. I feel like any errors that may have occurred were due to the use of the thermometer.
     I would like to repeat this experiment using more reliable equipment. I would also like to try it using paper coffee cups instead and see how much of a difference that makes. I would think using the paper coffee cups would result in a higher degree of heat loss. The Stoneware mugs proved to be too good of insulators themselves. It would also be interesting to see what a difference covering the entire mug in each material would make. Again I think this would be better seen using the paper cups. After working with the various materials it would also be interesting to combine the various materials to make the best insulator possible. I would have the students design a container to keep something like a bowl of soup warmest the longest.
     Overall I did learn more about heat and the use of insulators through this lesson. I learned how important it is to have equipment that is reliable to get more accurate results. I would like to repeat this experiment again using a better thermometer and different containers to keep the water in and see how the results compare. I think it would be fun to challenge the students to design a container to keep something hot longer. This would also bring engineering into the lesson.

As the pendulum swings...

The question I chose to focus on was: Which pendulum will come to rest more quickly- a lighter pendulum or a heavier pendulum?

The materials I chose to use were the three different washers and the string that was provided for us. First I massed the washers using my kitchen scale, although it fluctuated some the masses were about 1g, 8g and 20g each. I then made a pendulum using the 1g washer. I tied the pendulum to a wooden skewer which I taped down to the wine rack so the pendulum could freely swing.

Pendulum set-up

At first I was trying to hold it, but thought that my own movement may have caused the pendulum to move. Since I did not have a protractor to measure the angle, I let it go from a 90 degree angle since this would be the easiest to estimate each time. I timed how long it took to come to complete stop. I repeated this twice for a total of three trials and averaged the times together. I then repeated this with the other two washers being very careful to make the pendulum the same length and dropping from the same place. The average time it took the pendulum to stop, in seconds, for the washers were 1g- 188s, 8g- 291s and 20g- 537s.  I then used the virtual lab to test this out as well. In the virtual lab I set up two pendulums simultaneously with the same length, but various masses and let them go at the same time and each time the lighter one came to a stop first when friction was added. My initial thoughts were that the heavier washer would come to a stop first, but I now understand after the application that the heavier washer has more momentum, therefore taking longer to stop.

The main problem I had was just trying to figure out how to set up the pendulum. It took a little bit of creativity of looking around my house to figure out where it could be placed. I wish I had had a protractor so I could have measured the angle so I would not have to wait as long for the pendulum to stop. In the classroom I would probably have the students explore the different things that affect the period of a pendulum- the length, the mass, and the angle of release. I would stress to the students about only changing one variable at a time. I would have the students offer suggestions for other things that could be used as the bob of the pendulum. I would have my students explore what pendulums have been used for-ie grandfather clocks. I would want my students to learn about momentum and how it can be applied to this situation. This gives them a more hands on approach. I would have them suggest other ways we could experiment with momentum and real world applications. I believe I achieved my goal of understanding momentum better. Overall going through the guided inquiry process helped me to gain a better understanding of not only how inquiry works and how our students my go about the process, but it also I gained a new perspective on the concept itself. Overall the inquiry process is something that should be used in the classroom to help our students become better scientists.

Pendulum in motion

How to get kids excited about science

In teaching we use books a lot to teach our students. Sometimes we use a textbook and sometimes we use trade books. This week in class we read a lesson that used trade books to teach about roller coasters and then have the students design a roller coaster using items available at a local hardware store. While I was working in the library this week a book caught my eye it was called "Mr. Docker is off his Rocker" by Dan Gutman.

He has written a series of books called My Weird School Series where he writes about the various adults in the school. In this book a retired scientist comes to teach science at the school and he makes a clock run using potatoes, puts sodium in water, and makes a pendulum to name a few experiements. The main character A.J. does not like school, and thinks science is for nerds and doesn't think he needs to learn it since he wants to be a football player when he grows up. By the end of the book he is excited and wants to learn more about science and has a lot of why questions...maybe too many questions. It is really a cute little book and something you could read to your students to get them excited about science. The suggested reading level on the inside of the book is 2nd to 5th grade. Just wanted to share this with my fellow teachers.

Osmosis Egg Lab Part 1

This week we had to implement a structured inquiry lesson. Since I am currently substituting I have been working with one of the 5th grade teachers at the school. The students had been learning about plant and animal cells. I thought it would be fun for the students to see how the cell membrane works and explore osmosis. The first day we watched the BrainPop video on Passive transport found here http://www.brainpop.com/science/cellularlifeandgenetics/passivetransport/.

I used the experiment listed as my demonstration to give the students some knowledge about osmosis. The experiment used peeled carrots; one carrot was placed in a bowl of water and the other was placed in a bowl of salt water. A third carrot was left out as a control. We checked the status of the carrots at the end of class, but then left them overnight. The carrot in the water became stiff and was hard to bend because the water diffused into the carrots cells. At the same time the carrot in the salt water the water diffused out of the cells and the carrot became soft and very bendable.

Now that the students were armed with some background information we could work on our osmosis lab. The first step was preparing the eggs- to do so eggs were placed in a cup and covered with vinegar. The vinegar produces a chemical reaction with the shell and leaving the egg surrounded by the membrane. The students massed the eggs and predicted what they thought would happen to the eggs. The eggs were then placed in various solutions including:

Distilled Water

Colored Distilled Water

Salt Water

Karo Syrup

and

Molasses

The eggs were left overnight. The next day we observed and massed the eggs. All of the eggs in the water solutions gained mass while the eggs in the sugary solutions lost mass. Here you can see the eggs that were in the molasses and the Karo syrup lost mass and left dents in the eggs.

The purpose of using the colored water was the show the students that it is the water that is entering the egg, they compared it to Easter egg dying as that is what it looks like.



Here is one last shot of a very bloated egg.

After all the observations had been made we popped the membranes to see what would happen. Those that were in the water solutions produced geysers as all the water came shooting out. The eggs in the sugary solutions did not do much since the water had diffused out of the egg. Unfortunately we ran out of time to finish up their calculations and conclusions so we will continue our discussion this week and give them time to create their posters demonstrating how osmosis works. Examples of student work will follow in a few days. The students have been very excited to do some hands on activities and the teacher would like me to continue to work with her on new ideas and she was ecstatic to see how her students responded to this activity.

The lab was initially found here:

Bilash, B. & Shields, M. (2001). A demo a day- Biology. Flinn Scientific.

Some other references for the lab came from one of my favorite sites The Science Spot found here

http://sciencespot.net/Pages/classbio.html#Anchor-eggs

Recently on the NSTA listserv someone was looking for kitchen science lessons and someone else shared this sitehttp://www.exploratorium.edu/cooking/index.html



Melting Icebergs

This week we have been asked to consider the implications of what happens if the polar icecaps were to melt.



Image via Vanity Fair

Could this be a stunning realization in the future? From what I have read it all depends on which icecaps are melting. From what I have read most of the ice is located on Antarctica in the South Pole and if it were to melt the sea level could rise by 61 meters, but the average temperature is around -37C and most of the continent never gets above freezing, so it seems the ice there is not being affected. The reason for the potential rise in water is due to the fact that the ice is on land. Moving to the North Pole the ice is floating in the water and the sea level would not be affected by the melting ice. Another potential problem is that the ice is mainly freshwater, while the sea is made of salt water. This would change the salinity of the water affecting the animals living in the water.

But what other consequences are there of the melting ice caps, especially those in the Artic?



Photo via Ebuam's World

The polar bears habitat is melting out from underneath them and there is evidence of polar bears drowning, starving and cub deaths. Even though the polar bear spends a great deal of time in the water, it needs the land for its lively hood. Also with the ice platforms moving father apart the swimming conditions are more dangerous. The polar bears are not the only animals affected by this. With the Artic ice melting, the cooling layer over the Artic is disappearing, the Earth then absorbs more sunlight and becomes hotter. This rise in temperature is creating an increase in the population a certain beetle in Alaska which is destroying millions of acres of the Alaskan forest. To me although there is problems with the polar icecaps melting, global warming in general is a problem

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What other questions do I have about this science inquiry experience?

• At what rate are the polar ice caps melting?
• Is there a way to compare and contrast the land ice melting vs. the ice floating in the water melting?
• How would the salinity be affected if this was conducted in salt water versus fresh water?
• What are ways we can prevent global warming and equalize the Earth's temperatures so there is neither and dramatic increase or decrease in temperature?

Solcomhouse

This topic is very interesting and I am looking forward to continuing my research into the matter of the melting icecaps and global warming in general. I hope we as a society can change our attitudes and start turning things around.

A little chemistry humor



Soup to Nutz




 

STEM Strategies

insa

This week we were asked to write a lesson plan using STEM strategies. I found this very challenging. Is there truly a way to incorporate Science, technology, engineering, and mathematics into the same lesson? The school I was teaching at in TX was suppose to become a STEM school, but the district decided to concentrate on the high school first. Implementing STEM in any school would require a lot of collaboration between the teachers involved. Although I have a background in science with a chemistry major and math as math minor I am not sure that I effectively integrated the math into the lesson well enough. Also at the moment the extent of adding technology is having the students create PowerPoints. While I have grown up around computers I still do not know how to use half of the things out there. I have worked around teachers that have had their students create movies on movie maker, creating podcasts among other things. I do not know where to start with these things. It would be wonderful if there was a course on how to incorporate technology into our lessons where we would experiment with what is out there. This is my first time attempting a blog and they have been a round for a while. I know other teachers have implemented them into their classes.

Another twist given to us was the use of the 5E's- engagement, exploration, explanation, elaboration, and evaluation. This process is similar to what we have used before. In TX we had to use very specific plans, and the focus was always more on the vocabulary and what we did as a teacher and what the students would do. I like the 5E format better as I feel we get to explain more of what the students will be doing. However I wish we had a little more explanation about how to implement each section. I am not sure if I applied each section correctly.

The lesson I wrote dealt with infectious diseases where the students would simulate a disease spreading and would try to figure out where it started from. They would be given some math problems to figure out that if an outbreak were to happen for real how it could affect the school, town, state and country. They would then work in groups and study an outbreak that has happened in the past, find out why it happened, what was done to stop the outbreak and what has been done to prevent future outbreaks. I would conclude by discussing careers that deal with infectious such as immunology and epidemiology. The main logistical issue would be working with the math teacher to try and figure out the problems or if there is an algorithm for the students to use for their calculations. Other than that I think the lesson would work out well.

The Beginning

I am about to embark on a journey of uncharted territory for myself. While I read several blogs daily, I have never had one of my own. This blog is part of requirement for a course I am taking at the moment, but I hope to continue to blog beyond class. As I become more comfortable in the blogging forum I may start another one to chronicle my many travels while living abroad. Stay tuned and enjoy!