It's Too Darn Hot!

For my experiment with heat insulators, I used thick ceramic mugs which could hold about two cups of liquid, a tea kettle and water, long rubber bands, foil, a car advertisement which was made from thick shiny paper, Saran Wrap, a tea clothe, and a big leaf off of a house plant, and the thermometer given to us by Walden. I chose the mugs because they were what was available which did not have wide brims. Other mugs would have let heat out faster because of more of an open area. I chose the foil because I was curious to see how much it transferred heat. So often it is used in cooking so I wanted to test it out. I used Saran wrap because it is also used quite a bit in cooking and I do not really think of it as being an insulator as much as a protector or eliminator of contaminants. I wanted to see how useful it could be at holding heat and I thought that the ability to hold in steam would work in its favor. I chose the tea clothe because they are used to wrap around bread when it is fresh out of the oven. I didn’t think that it could work too well and I wanted to see if I was right. I chose the house plant leaf because it seemed odd enough to really spice up the experiment. In South America banana leaves are used for cooking things in. I wanted to see how well this would work. I didn’t really expect too much out of it, but at the same time, the rubbery and water tight nature of the leaf caused me to think that its performance might shine out.
The results of my experiment was that it was a flop. In my efforts to protect the heat of the water and do everything for insulation’s sake, in thirty minutes I had four cups with water still high above the point of my thermometer being able to measure it. So high above, in fact, that there was no way to compare any of the scenarios. So, I tried it again, this time I waited until the water was right at 120 degrees (the highest mark on the thermometer) before I put the “lids” on. In the second experiment, I checked each one at 20 minutes and 30 minutes. Here are their times respectively: foil, 106 degrees and 99 degrees Fahrenheit; tea towel, 105 and 97 degrees Fahrenheit; slick paper, 104 and 98 degrees Fahrenheit; Saran Wrap, 108 and 99 degrees Fahrenheit; and lastly house plant leaf, 110 and 100 degrees Fahrenheit. All of the experiments were close, but the Saran Wrap and plant leaf were the highest. This causes me to believe that it is the water proof things that do the best in this case but I think that the steam would be the reason for that.

Answering Questions:
“What other items might you like to test, other than water? Why might these items cool faster or stay hot longer?” I think that something like hot dogs might be a good idea because the heat will be less gaseous and more solid/conduction related. I think that a leaf might still work, but other materials might shine out more with a different movement of heat which is not water related. I would love to test out bread and potatoes. Potatoes should have a much longer cooling time. They seem to hold heat well. However, I would love to test something like eggs and try to find a good way to keep them warm without overcooking them.

How might you set up this or a similar experiment for students in your classroom? How could you make this experiment more fun, interesting, or engaging for your students? How might you design this experiment so that it is relevant to students’ lives? I think that I would use a prompt to make it more interesting for my students. I would ask them to think of something during the week that they eat and really enjoy which is hard to keep nice and warm. I would ask them to also bring in things that they already use at home to keep things warm. After that, we can go from there at testing materials out to see which works better and also test different items to see what works best for them. I would let the students know that if we find anything conclusive that we are going to prepare our information to share it with others and help others to share in our new understandings. Part of what we put up will be an area where people can respond to what we posted with their thoughts, comments, etc.

A Swinging Pendulum

Setting the basis for the work:

I chose to do an experiment based on the question of: what type of pendulum takes longer to come to a state of rest, a light or heavy one? I started out holding a string with a washer on it and counting one-one thousand. That was a fool-hardy idea. After a while I found my cell phone had a stopwatch option and I used some old yearbooks, the string and washers from our Laureate kit, plus a medium-small washer I already had (any washers graduating in size and weight should work), and an old broken children’s sunglasses arm to string the string through and hold it out at a couple of centimeters from the books and side of the table. I tried to tie a knot on the washer side which balanced the weight as best as I could, and I measured the string out 12 inches from the washer to the sunglasses arm. Holding the string level with the books with my hand above the washer, and using my other hand to tap the stopwatch button, I took time measurements for each washer at least three times.
The issue of what exactly constitutes rest was major because the washer never did come to a full rest. Each time it would just keep going, moving from a side to side motion into a more circular motion. Sometimes the wind would blow through the window, or a person would walk by and these motions would cause the washer to alter course. That being said, I carefully watched the washer for indications that the motion was no longer side to side and then I stopped the stopwatch. I also used the smallest washer as an anchor to rest all other washers on, so it was included into each and every experiment. With that in mind, my final calculations reached averages of small, 2.40.77; medium-small & small, 3.21.64; medium-large & small, 3.54.90; and large & small, 6.26.85. Thus, without any doubt, it is clear that the weight of the washer did indeed impact how long it took before the pendulum came to a rest. I did actually expect this to be the case, but the experiment confirmed it.

What went well during the experiment? What did not work well?

The idea of stopping the stopwatch when the pendulum was not REALLY at rest bothered me. I should like to have a better measurement than the human eye guessing at when to stop!
Also, the whole reason behind the sunglasses arm was because the string was rubbing up against the books and friction was stopping the swinging motion on one side. At other times when first starting a measurement, the pendulum would also hit the table, or books and thus that messed up the measurement as well. So, the arm was my solution, but even then there was room for the string to slide around a little bit and I would have preferred for that to not be the case.

Based on your past experiences with scientific inquiry, what modifications would you make to this experiment to get a different or modified result?

I think that another modification would be to make a hook from a paperclip and use that to hang the washer off of. Perhaps this would help keep the balance more correctly and also allow for only one washer to be measured at once. This would not change the comparison, either way, more weight would still mean more time, but it would create a more clean presentation. Yet another issue, I believe, which would improve the experiment would be to use the same washer, just adding more. The reason why I would do that is that the washers were not equally different. I had no scale to weigh them on, but some were thicker than others rather than just wider in diameter. Also, some seemed to be made out of aluminum while others out of a stronger, heavier metal. Thus, I have no real way to give you the right data to replicate this experiment, even if I were to give you diameter measurements for the washers, apart from perhaps both of us having the same Laureate Inc. Science kit.
I also noticed that the string kept oscillating. It would go in a general back and forth motion but occasionally it would move a couple of degrees one way or another. I do not have the reason for that, but perhaps the knot made is involved.

How might you set up this or a similar experiment for students in your classroom? How could you make this experiment more fun, interesting, or engaging for your students?

I have set up this sort of experiment for my students, only they were trying to use the force of gravity on the washers to move books off the table when the books were placed on wax paper, regular paper, no paper, and a towel. Setting up this experiment for students would not be hard, but getting them to identify the concerns that I listed above would take training. Only a trained eye, or at least an observant eye would notice that the string is rubbing against the books and altering the experiment. As far as more fun or interesting, I really do not know at the moment. I will have to really think about that one for a while. It is actually pretty boring to watch a string moving back and forth and wait for it to stop moving over a length of time which is close to five minutes.

How might you design this experiment so that it is relevant to students’ lives?

Perhaps we could use swings instead and let the children be the mass in that case. I don’t know, but I believe that they would at least enjoy themselves more that way. Another aspect is to create a meaningful reason for this, or to answer the question: “So what?” Why would students want to learn this? Why is it valuable or useful to them? If I currently had an answer to that, I believe that creating a fun and interesting experiment would flow naturally. However, at the moment I do not know what environment would cause them to need to know this.


What specifically would you like students to learn from this experiment? Did you achieve this goal?

While I was creating this experiment, a child/friend of mine came by. She wanted to touch the string and I had to quickly stop her from altering my trial run. To her it is a game just to watch the pendulum swinging. She started to talk about it and she was under the impression that the weight of the washers would slow down the string rather than lengthening the time in which it moved. I believe she thought this because big things often move slower than light things when they are things like cars or trains. What I don’t think that she understood is that those things are also harder to stop because of inertia. Her parents wanted her to go take a bath so I could not include her in witnessing my experiment, but I would want her to experience this experiment just so that she saw the importance of trying things out and checking hypothesis and changing misconceptions. Yes, a heavy wagon is slower to get started, but try and take that cart down a hill and see if the wagon isn’t ready to roll you over! Students do not experience this as much today because children do not need wagons. Their parents often drive them everywhere! So, if nothing else, this experiment could be a lesson in creating, and running and experiment, and re-adjusting a hypothesis as you go. I don’t think that student have any greater a teacher than to see for themselves how their expectations did not work out like they thought. If something goes differently than expected, they do not feel corrected, or called out. It is the human aspect, the attention of a teacher or colleague that can make them feel self-conscious about being “wrong”.