Heat Transfer

In this weeks’ application inquiry, I chose four different materials to test their ability to insulate heat.  Four identical mugs were filled with the same amount of the same temperature water.  On each cup a different material was placed on the top and secured with a rubber band.  After thirty minutes the temperature of the water in each cup was recorded (see appendix for table).  The insulators I chose were faux fur, plastic bag, paper towel, and tin foil.
            I chose the fur because I thought it would be a good insulator and I chose the paper towel because I thought it would be a poor insulator (?).  {good insulator and poor conductor mean the same thing} The others I chose because I was just curious.  I also included the students in my class, I presented them with ten different materials to use as insulators and they chose four of them.  The faux fur was the best insulator; the temperature did not decrease by that many degrees.  {Since you measured the initial temperature, you could use that information here.} The next best was the plastic bag.  I was surprised that this, I did not expect the plastic bag to be a good insulator because it is so thin.  Although, it is hard for air to escape from a plastic bag so maybe that had an effect on it.  The paper towel was the third best insulator.  I did not think that the paper towel would do a good job because it was a cheap paper towel that was thin and single ply.  The worst insulator that I chose was tin foil.  This was surprising because one of the reasons people use tin foil is to cover hot dishes to keep them warm.  I am sure that using faux fur to cover lasagna would be very messy, but it would keep the lasagna the warmest.  I think a good experiment would be to find the best type of material (that would be appropriate) to cover food to keep it warm.

Other materials I might choose - saran wrap, paper, fleece, Under Armor cold gear, stocking socks - I think the best would be the Under Armor

Other materials I would want to test - any hot food products - to see which material would keep the food the warmest

How would I set this up for my classroom? I think I would set this experiment up in the same way - I think that reading the story of Goldie Locks and the Three Bears was a good introduction.  I think my students would like being able to set up their own experiment.

Learning objectives for my students - what materials are the best insulators, different types of heat transfer (conduction, convection, and radiation) -

Engaging in Guided Inquiry

The question I chose was “How do different surfaces affect the momentum of marbles?”

The process:

-        --- Choose three different surfaces, have 2 different sized marbles, and a ramp

-       ---   At each surface place both marbles at the top of the ramp and release the marbles – notice what happens to each marble

-        ---If you have a floor that is slightly slanted you can roll the marbles towards a wall or raised threshold to see how the marbles roll back towards the ramp

-        ---Rolled the marbles from the ramp at least 3 times at each surface

What happened in the experiment:

·         tile floor = both marbles were rolled from a ramp (they weren’t pushed, they were just placed at the top and released) towards a raised door threshold – the large marble bounced off and then stopped close to the threshold – the small marble bounced off and almost rolled back to the ramp – the tile floor is on a slight slant so I placed the marbles next to the threshold and let the marbles roll down the slant, the larger marble always got to the cabinets first, it picked up more speed than the smaller marble

·         carpet floor = both were rolled from a ramp (they weren’t pushed, they were just placed and started rolling) - the smaller marble went farther  

·         wood floor - both were rolled from a ramp (they weren’t pushed, they were just placed and started rolling) - towards a wall – both marbles hit the wall about the same time and started rolling back, the larger marble picked up more speed and made it back to the ramp before the small marble did, the small marble had a hard time picking up speed after it hit the wall – on the wood floor the marbles rolled the smoothest, there were not bumps to make them stop rolling

These were basically the results I expected.  I didn’t think there would have been such a difference in the speed of each marble on the slanted floor.  I was surprised that it took the smaller marble a longer time to bounce off the wall and start rolling the other way.  I thought that the larger marble would have done that.

Everything went well in this experiment.  I didn’t really have any problems.  I didn’t realize that my floor was slanted, but it kind of worked out and added something to the experiment.

Modifications: different sized ramps, a true flat surface (no slanting), an extra large marble and a super tiny marble to exaggerate the difference 

I think I would set this experiment up the same way.  I would have the students choose one question and come up with an experiment.  In my classroom I would have had many different objects that students could use to see momentum. 

Making the experiment relative to students’ lives: what happens to objects in cars during a crash, what happens to groceries in the car when you are driving home

What I would like my students to learn:  how different surfaces affect momentum, how different masses affect momentum – I learned these things from this experiment.