Marius Maduta
Klein Forest High School, Klein ISD
Timeframe:
Total # of Instructional Days: 9
Subject: Pre-AP Physics
Grade level: 11th grade
E3 Final Report
My classroom project was based on (Texas A&M faculty) Dr. Sy-Bor Wen’s research,
Experimental and Theoretical Analysis for Optical Induced Thermal Energy Transport in NanoOptical Systems with Pulsed Light Sources, which, in turn, focused on the analysis of the
interaction between energy (generated by various pulsed laser light sources) and a variety of
materials. The actual classroom project involved a study on Reflection, Refraction and Heat
Transfer using laser. Most of my students were already familiar with laser pointers. The
classroom project was meant to allow the students to research the topics mentioned (reflection,
refraction and heat transfer with light), and develop various experimental setups in order to
present the topics in an applicative way. My students were already familiar, albeit vaguely, with
some ordinary applications of laser technology. From the laser used in their CD players, simple
laser pointers, even laser surgery (Lasik and Endovenous Laser Ablation) and security systems,
they have already encountered a wide range of applications of lasers.
Design of the Project
There were a total of eight days allowed for the project. The students were expected to
design a setup that would show heat transfer from a laser light (or other light sources). Laser
pointers with a power of 100 mW were available (green and blue - the red laser was only 25
mW, because the 100 mW red laser broke down three days before we began the project). The
students also had lenses available to them (both for converging the light rays and for using with
reflection and refraction setups), as well as mirrors. Both converging and diverging lenses and
mirrors were made available, as well as plane mirrors.
Marius Maduta
Klein Forest High School, Klein ISD
Timeframe:
Total # of Instructional Days: 9
Subject: Pre-AP Physics
Grade level: 11th grade
Before the actual project, the students took the pre-test (on November 18th). At that time,
the students were not familiar with the nature and characteristics of waves or with any part of the
light unit. We began studying the Waves unit in March, and this project took place immediately
after we finished the Sound sub-unit.
Day 1: Lasers were introduced and explained. The students were presented with the basic
notions about lasers as well as laser safety.
Day 2: The Engineering design and discussion took place next. The students were introduced to
various aspect of the engineering design (Stating the problem, Brainstorming ideas, Deciding on
a solution, Designing the device, Evaluating the device, Building the device, Testing the device,
Building the final product).
Day 3: Lasers and laser safety quiz. After the quiz, the projects and assignments were described
and assigned (the class was divided into groups of four or five). Two groups worked on
Reflection, two groups worked on Refraction, and the other two groups worked on Heat Transfer
with Light.
Day 4: The students began working on researching their topics.
Day 5: The students began working on designing their projects.
Day 6: The students continued working on their project design.
Day7: The students began presenting their projects. There were two groups that presented each
day (initially, three groups were planned to present each day, but their presentations took longer
than planned, so we ended up taking three days for presentations). Reflection and Refraction
were presented.
Day 8: Project presentation continued. Reflection and Heat Transfer were presented.
Marius Maduta
Klein Forest High School, Klein ISD
Timeframe:
Total # of Instructional Days: 9
Subject: Pre-AP Physics
Grade level: 11th grade
Day 9: Project presentation concluded. Refraction and Heat Transfer were presented.
Therefore, two groups presented Reflection setups; two groups were responsible for
Refraction; and two groups for Heat Transfer. During the presentations, the rest of the class was
expected to take notes and ask clarification questions. The post-test was administered the
following day.
Explanation of the projects:
The groups began by explaining the basic concepts of their assignment, after which they
proceeded to show the practical application of their designs. Each group was expected to supply
the rest of the class with probing questions and a homework assignment (in the form of two to
five questions). One of the Reflection groups presented mostly design - plane and curved
mirrors. Their theoretical explanation was minimal. The other group that worked on Reflection
supplied much more theoretical content. The first group had only a definition and a brief mention
of the Law of Reflection, while the second group had a more detailed explanation of the Law of
Reflection (with diagrams). Their designs included using the laser to show the Law of Reflection
("the angle of incidence is equal to the angle of reflection"), as well as using the light ray box
with both plane and curved (convex and concave) mirrors.
Both of the Refraction groups presented very detailed PowerPoints on the topic of
refraction and Snell's Law. The first group provided mostly theoretical aspects of refraction,
while the second group provided more examples and practical applications of refraction. Their
design included the "Jelly Marbles", or hydrogel marbles, which, when placed in water, absorb
the water to increase several times in diameter. When placed in additional water, their index of
refraction which is similar to that of liquid water, makes them virtually invisible and
undistinguishable from the liquid water in which they were submersed. Another design was the
Marius Maduta
Klein Forest High School, Klein ISD
Timeframe:
Total # of Instructional Days: 9
Subject: Pre-AP Physics
Grade level: 11th grade
total internal reflection shown through a jet/stream of water flowing from a five gallon container
through a hole on the lower side of the container. A laser light was projected from the opposite
side, and it continued to be totally internally reflected in the bending water jet. One of the groups
used an on-line applet to show refraction and total internal refraction. Refraction was also
demonstrated with a laser light passing through a piece of fiber glass. The same group also used
a wave tank (with transparent sides) to show how light "bends" as it passes from air into water.
There was not too much theoretical presentation of the Heat Transfer with Light topic.
The Heat Transfer with Light had several ideas they put in practice. One group used a convex
lens to focus the light from a 100-mW laser onto the surface of an inflated balloon in order to
melt it. When exposed to the laser light or a few seconds, the balloon melted at that point and
popped. The same group placed a black balloon inside a white balloon and then exposed it to the
laser light. The black balloon inside melted and popped, while the outside remained intact. The
same group used the focused laser light to light up a match stick, but was unsuccessful. The other
group initially planned on using "the Torch," a 100-W flashlight in order to transfer heat, but did
not manage have it delivered on time. Their project was not very successful, as they ended up
using just a flame.
I was pleased with some of the projects, and not so pleased with others. The hydrogels
worked well, as did the total internal reflection using the five-gallon container. Also, the heat
transfer with lasers and balloons worked especially well. The PowerPoint presentations were
fairly clear and well done. In my view, the limited amount of resources made parts of these
projects unsatisfactory. There was also not enough time allocated to each topic. In order for the
class to benefit from these presentations and designs, time proved to be of essence. Those
presentations that included a PowerPoint were more efficient. From my perspective, the
Marius Maduta
Klein Forest High School, Klein ISD
Timeframe:
Total # of Instructional Days: 9
Subject: Pre-AP Physics
Grade level: 11th grade
Reflection designs were poorly conducted. They seemed to lack the real-world relevance. There
was no explanation of a ray diagram or a "usable" application design. The online applet on
refraction and total internal refraction did not work so well, mainly due to the time constraints.
The students received it well for the most part. I believe they showed real interest in the
designs presented by the other groups. As a matter of fact, it became quite competitive, as some
groups wanted to exceed the accomplishments of previous ones (that is, incidentally, one of the
reasons why I believe that next time I will limit each topic to only one group).
Next time, I will detail my expectations to include between 7 and 10 minutes of theory
presentation, followed by no less than three designs. That way, there will be a better balance
between the theory and practical application aspects. I will also require each group to have a
PowerPoint presentation, and I will allocate one class period to each group, even if I have to
allow the groups to be larger than five students. Because my classroom is under a closely
prescribed curriculum, I reserved only a little more than one week to this entire project. But
adding the class size, I now realize that I will need at least 12 days to do this well. My initial
impression was that two groups would provide a much-needed repetition of the subject matter so
that the students will have double exposure to each topic. However, it seems that one larger
group with more time may be a wiser choice. I will have to set some time aside in the beginning
to introduce each topic and have the entire class understand the basics of the Law of Reflection,
Snell's Law and Heat Transfer well. Then, I believe the students will be better able to concentrate
on the engineering design process and practical application aspects.