Heat Transfer Inquiry

The materials that I used for this experiment are the following; four mugs, 4 rubber bands, a measuring cup, scissors, a ruler, a tea kettle,  a candy thermometer, plastic wrap, aluminum foil, one dish towel, a piece of  card stock paper,  and a kitchen timer.  I first filled the tea kettle with tap water and turned the burner on high heat.  Then as the water was heating up, I got all my materials ready for the experiment.  I cut the plastic wrap, aluminum foil, and dish towel using scissors and a ruler to a 11.5 inch by 8 inch piece so it would match the size of the card stock.  I then found four rubber bands and four mugs that were exactly the same.  I got four measuring cups and got them ready to fill to the half cup line.  Once my tea kettle was whistling, I first poured the water into one of the mugs and measured the water temperature.  It measured 210° F the first trial, 208° F the second trial, and 211° F on the third trial.  I did this because I wanted to know the starting temperature before covering the hot water with various materials.  I filled each measuring cup to the half cup mark and poured the hot water  into the mug and then covered the top with a material and put a rubber band around it to hold the material on top.  Once all four were covered and held down with the rubber band, I then set the kitchen timer for thirty minutes.  After the thirty minutes were up, the timer went off, and I quickly removed each rubber band and the material, and then took the temperature of the water using the candy thermometer.  I repeated this process for all the mugs and then recorded the temperatures of the water.  I then did the experiment two more times to complete two more trials.  Here is the data that I recorded.

aluminum foil	plastic wrap	card stock	towel
120° F	110° F	105° F	110° F
122° F	112° F	105° F	111° F
123° F	111° F	104° F	112° F

        

There were some challenges that I experienced during my heat transfer guided inquiry experience.  What didn't go so well was that it was a long and difficult process to get a thermometer that worked well for the experiment.  I took the temperature of the water for each trial before I covered the mugs with the various materials.  The first time I went to take the temperature of the hot water, it broke the thermometer that came in our science kit for this class.  I think it was due to the drastic change of temperature and the heat expanded the liquid and broke the glass of the thermometer.  It also could have been that it had a crack in it already.  I had my daughter go to the store and pick up a thermometer at the grocery store.  She came home with a digital thermometer.  This one didn’t work because it did not measure temperatures that high.  The next step was to go the grocery store myself and look at various food thermometers and see if one of those would work.  I knew the thermometer needed to be able to measure high temperatures as well as show specific temperatures so my data would be accurate.  I thought the candy thermometer would work the best and when I got back to my house to conduct the trials, I knew that it was the right choice. 

To extend this experiment, I would challenge students to come up with a container that would keep the food warm for the longest amount of time.  After the containers were made, I would pop some popcorn and have students test their containers.  

Scientific Inquiry

I chose the following question.  Which pendulum will come to rest more quickly-a lighter pendulum or a heavier pendulum?  I used the string, 3 different size washers, scissors, the largest nail, and a ruler.  I cut the string in half so that it would not be too long.  I tied the string around the top of the nail and around the large washer.  At first I tried to hold the long nail on the kitchen counter and realized right away that this would not work because the washer hit the kitchen cabinet.  Instead I used a ruler that can be held in a three ring binder.  I put the nail through the middle hole in the ruler and was now able to create a pendulum that did not hit anything.  At the beginning of each trial, I held the washer that was attached to the string and held it parallel with the kitchen counter.  The largest washer took a long time to come to a rest.  The average of the three trials for the largest washer was nine minutes and ten seconds.  Next I followed the same procedure with the medium washer and then the smallest washer.  The medium washer only moved for an average of five minutes twenty-two seconds.  The smallest washer was done moving on average at one minute thirty seconds.

Before conducting the experiment, I thought the largest washer would take the longest time to come to a rest.  The reason why I thought this is because I thought the mass of the object would keep the momentum going longer.  For example, it would take more energy and time to stop a freight train as opposed to stopping a motorcycle.  In addition, I was thinking about Newton's third law, for every action there is an equal and opposite reaction.  If the pendulum is heavier, it will swing higher than one that has less mass based on the equal and opposite reaction.  I was correct in thinking that the heavier pendulum would take longer to come to a rest.  I was, however, surprised by how long the largest washer took to come to a rest.

I thought using the same string, ruler, and nail went well in terms of keeping the variables consistent and only changing one variable, which was the three washers with different masses.  What didn't go so well was that it was hard, if not impossible, to start the timer at the same time as I let go of the washer.  This would have been easier to do with a partner to get my times more accurate.  In addition, it was hard to hold the ruler in between my fingers on the kitchen counter without moving for so long.  I tried to set it up differently so objects were holding the ruler up on the counter, but nothing seemed to work.  I tried cans of V-8, books, full bottles of laundry detergent.  The nail was too heavy and it would all fall forward.  As I am writing this, I am thinking maybe, I should have tried a lighter nail!!!

To set this up for students, I think I would have them do the pendulum experiment based on mass similar to what I completed. To extend the experiment, I would have students use the same mass for the pendulum, but change the length of the string.  I think to make the experiment engaging and fun, I would give students various objects and they would need to create a pendulum, similar to how our experiment was set up.

I would want students to learn that pendulums with less mass come to a rest faster than pendulums with a heavier mass.