For this week's experiment with heat transfer, I chose the following four materials to investigate as insulators: paper (paper towel), plastic (baggie), cloth (cotton dishrag), and aluminum foil. These materials were selected because of their different makeup of particles. For example, the paper towel and cloth had tiny holes where air and heat could have escaped during the experiment. The plastic had a very solid particle makeup, along with the aluminum foil. I thought that the plastic would be the best insulator because it seemed to be able to create the tightest seal over the hot water. Upon conducting this experiment, I found that the aluminum foil worked as the best insulator to keep the water the warmest. My hypothesis, the plastic baggie, came in second place. The experiment's results made perfect sense because the whole purpose behind using aluminum foil is to keep hot foods warm and cold foods cool.
If I were to conduct this experiment again, I think that I would like to test out saran wrap as an insulator. I think that it would be a good choice because it is used along the same lines as aluminum foil. I also think that it would help to trap the heat and keep the water warm. Another material that would be interesting to test would be rubber. I have a rubber glove that I use to do dishes. I wonder if the rubber would be a better insulator than the aluminum foil. My hypothesis would be that the rubber is the thickest of the other insulators and would have more material to help insulate the hot water. This would be an interesting extension to this lesson.
If I were to set this experiment up in my classroom, I would gather a bunch of materials that could potentially be used to test as insulators. I would set up the parameters the same, however I would introduce the experiment the day before and show the students the materials that I planned on providing. To make this activity a little more fun and exciting, I would turn it into a competition telling the students that the group that can keep the water the hottest after thirty minutes will receive a prize. Also, to engage them further, I would allow the students to bring in any insulating material that they have at home to use for the experiment. This would provide the opportunity for those that are especially intrigued to go home and hunt for additional materials to test out. Another way that I would make this relevant to the students' lives would be to set a purpose for the experiment. I would type up a scenario that explains that reason for wanted to keep this water hot as long as possible. A real world reason could include the delivery of soup to a sick person's house or even the delivery of a top secret liquid to a special science laboratory that is thirty minutes away. As the liquid cools, it loses important enzymes and the students would need to deliver it as warm as possible. These would be two possible situations that would give the students a purpose in this activity that has meaning.
From doing this activity, the students would learn what materials make good insulators, as well as the different ways that heat transfer occurs. More specifically, I would hope that the students would be able to apply this knowledge to their personal lives when needing to keep something hot. I also want to provide the students with hands on experiences that they can draw from when they are confronted with questions about conduction, convection current, radiation, insulators and conductors. If the students can form these mental connections, the chances are greater that they will internalize the material and perform better on tests. We are just finishing up a study on heat transfer and I really think that my students have learned a lot because of the experiments and inquiry that have been done in the classroom. For example, we checked different materials of hats to find the best insulator for your head. This is a great extension to the above activity, especially to see if the material that insulates a mug the best is the same material that insulates your head most effectively.
In conclusion, this experiment taught me first-hand the insulating potential of different material. It also intrigued me to ask questions and to make further extensions based on the initial inquiry. Finally, it was easier for me to make connections when reading the definitions of conduction, convection current and radiation because I had seen some of the heat transfers in this experiment, especially conduction and the convection current. What a simple activity to produce so many additional discoveries and questions!
Sunday, November 21, 2010
Sunday, November 7, 2010
Guided Inquiry: Which pendulum will come to rest more quickly?
This week I investigated the question of what size pendulum will come to rest more quickly. To perform this experiment, I collected all of the materials. This included two different sized washers (one small and one large), string, a ruler, a desk, a timer, and a pencil. The setup included measuring out 30 centimeters of string and tying one end onto a pencil that is taped off of the edge of a desk. The other end of the string was tied to a paperclip that was engineered into a hook. This initial setup made it very easy to attach the different washers without having to worry about the length of the string varying.
During the experiment, I tested each different size by timing how long the pendulum took to stop swinging. Each time I would make the string taut and raise the washer to the edge of the desk. I would then let the string go and start the timer to see how long it would take to stop moving. I repeated this test with each size washer three times. After I collected all of my data, I averaged the results to find the answer to the question of if a large or small washer would come to rest more quickly. My results were that the smaller washer came to rest a lot faster than the larger washer. This was my initial hypothesis based on my knowledge of momentum and that fact that the larger washer had more mass. I know that momentum is the product of velocity and mass, so with more mass there would have to be more momentum. My hypothesis was supported in that the smaller washer stopped swinging faster than the larger washer.
While I was conducting the experiment, everything went well and it was easy to conduct and record my results. I initially had two different pendulums, one with the smaller washer and a different one with the larger washer. It was very hard to make sure that the string was the same length. That was when I decided to use one string and a paperclip to help keep that variable the same. It was frustrating when I was trying to tie on the separate washers. I had the same length of string measured out, but my knots were not identical. When I revamped my initial setup, I had on problems during the experiment. Also, I was going to use a ruler to see how high to drop the pendulum, but I decided to simplify that by going from the edge of the desk. This was a great choice because I know that not having to measure to a certain height each time would be easier for my fourth graders. All they have to do is pull the string tight and raise it to the desk and let go. The simpler the better.
Based on my past experience with scientific inquiry, a modification to get a different result could be to focus on the length of the string. If I were to stay with the same size washer and just change the string length, we could investigate if the length of the string affects the amount of time that the pendulum swings. This would be a different variable to test. We could also keep the length and the washer the same and change the height from which we start the pendulum. That would also produce different results. The children would find out the at the greater the potential energy stored, the more kinetic energy will be released. That would be a great connection between momentum and potential versus kinetic energy.
I would set this experiment up in my classroom in the exact manner that I did the experiment. I had my students in mind when I designed the guided inquiry activity because I always like to make things relevant to the fourth graders that I teach. I think that it would be fun to try three different washers: small, medium and large, and collect data on all three. I also think that it would be fun for the kids to measure the mass of the washers using a triple beam balance before they conduct the experiment. This way they would also get practice manipulating this very important scientific tool. After answering the initial question, it would be really neat to propose to the student the challenge of creating a pendulum that will swing the longest and having a class competition. They love to be challenged and really like working towards a goal. I would set it up as if they were designing a new amusement park ride and the people that were hiring them wanted to get the longest ride possible from the initial drop. All of the students have schema related to an amusement park and this would engage them. The only catch would be that the experiment would have to be able to be replicated numerous times in front of the class. This would encourage them to record their data. I plan on using this activity when we do our lesson on forces in the spring.
Specifically, I would like the students to understand that the more mass an object has the more momentum it will produce. I would also like them to see that energy can be stored and released. I achieved this goal through my discovery during the experiment. I am certain that my students will see the results as well. I especially would encourage the use of a balance to measure the mass of the washers prior to the experiment. I know that the students can see that one has more mass, but I really would like to reinforce the use of the triple beam balance as well. Hopefully, upon completion of this activity, the students will bring momentum to life and will be reminded of the science behind rides the next time they get on a pirate ship at an amusement park.
During the experiment, I tested each different size by timing how long the pendulum took to stop swinging. Each time I would make the string taut and raise the washer to the edge of the desk. I would then let the string go and start the timer to see how long it would take to stop moving. I repeated this test with each size washer three times. After I collected all of my data, I averaged the results to find the answer to the question of if a large or small washer would come to rest more quickly. My results were that the smaller washer came to rest a lot faster than the larger washer. This was my initial hypothesis based on my knowledge of momentum and that fact that the larger washer had more mass. I know that momentum is the product of velocity and mass, so with more mass there would have to be more momentum. My hypothesis was supported in that the smaller washer stopped swinging faster than the larger washer.
While I was conducting the experiment, everything went well and it was easy to conduct and record my results. I initially had two different pendulums, one with the smaller washer and a different one with the larger washer. It was very hard to make sure that the string was the same length. That was when I decided to use one string and a paperclip to help keep that variable the same. It was frustrating when I was trying to tie on the separate washers. I had the same length of string measured out, but my knots were not identical. When I revamped my initial setup, I had on problems during the experiment. Also, I was going to use a ruler to see how high to drop the pendulum, but I decided to simplify that by going from the edge of the desk. This was a great choice because I know that not having to measure to a certain height each time would be easier for my fourth graders. All they have to do is pull the string tight and raise it to the desk and let go. The simpler the better.
Based on my past experience with scientific inquiry, a modification to get a different result could be to focus on the length of the string. If I were to stay with the same size washer and just change the string length, we could investigate if the length of the string affects the amount of time that the pendulum swings. This would be a different variable to test. We could also keep the length and the washer the same and change the height from which we start the pendulum. That would also produce different results. The children would find out the at the greater the potential energy stored, the more kinetic energy will be released. That would be a great connection between momentum and potential versus kinetic energy.
I would set this experiment up in my classroom in the exact manner that I did the experiment. I had my students in mind when I designed the guided inquiry activity because I always like to make things relevant to the fourth graders that I teach. I think that it would be fun to try three different washers: small, medium and large, and collect data on all three. I also think that it would be fun for the kids to measure the mass of the washers using a triple beam balance before they conduct the experiment. This way they would also get practice manipulating this very important scientific tool. After answering the initial question, it would be really neat to propose to the student the challenge of creating a pendulum that will swing the longest and having a class competition. They love to be challenged and really like working towards a goal. I would set it up as if they were designing a new amusement park ride and the people that were hiring them wanted to get the longest ride possible from the initial drop. All of the students have schema related to an amusement park and this would engage them. The only catch would be that the experiment would have to be able to be replicated numerous times in front of the class. This would encourage them to record their data. I plan on using this activity when we do our lesson on forces in the spring.
Specifically, I would like the students to understand that the more mass an object has the more momentum it will produce. I would also like them to see that energy can be stored and released. I achieved this goal through my discovery during the experiment. I am certain that my students will see the results as well. I especially would encourage the use of a balance to measure the mass of the washers prior to the experiment. I know that the students can see that one has more mass, but I really would like to reinforce the use of the triple beam balance as well. Hopefully, upon completion of this activity, the students will bring momentum to life and will be reminded of the science behind rides the next time they get on a pirate ship at an amusement park.
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