Vernier Technology: In the Lab or on the Go!

Acid-Base chemistry is a topic that is extremely important on the AP Chemistry exam and can be used to explain a variety of phenomena in our bodies, other living things, water chemistry, earth science, and many other areas of science.  The complexity of acid base equilibria can be mathematically daunting for students.  Furthermore, the concepts of buffer systems and titration curves are easily confused if visual stimuli are not present.  Vernier technology is the answer to these educational challenges.  Through the use of Vernier pH and temperature probes, measurements of acids and bases can happen in the classroom as well as in the field.  The graphing programs that are built into each protocol provide many ways to view and manipulate data.  The Graphing program easily manipulates raw data into various derivatives, inverses, and exponential adjustments to account for just about every mathematical relationship that it out there in our scientific world. 

            The ease of use is the greatest triumph for this software.  It only requires a few attachments tom a computer and you are on your way.  I personally like to use what are called “Labquests”.  These are handheld units that have the protocols programmed in to them so that you could perform an entire lab with graphed results while you are still in the field.  It is great for environmental chemistry field trips testing water quality and comparing it to the existing biota. These materials are expensive but Vernier products if handled properly will last a very long time and they are extremely valuable to student manipulation of scientific data.

Check out the website listed below for a list of all the areas of science that Vernier has tools for.  These instruments and protocols will help shape student minds for the types of analyses the future holds, and I am a faithful subscriber and user of them.  

http://www.vernier.com/

The Heat is On

For my insulator test, I used four coffee mugs of hot water at 50⁰C.  The insulators I used for my mug coverings were aluminum foil, cotton T-shirt, newspaper, and plastic wrap.  My results were as follows:

Data Table

Recorded Water Temperatures (0C)	Material
	Foil	T-Shirt	Newspaper	Plastic Wrap
Initial	50	50	50	50
Final	43	43	40	42
Temperature Change	8	7	10	8

I had originally hypothesized that the foil would be the weakest insulator, simply because it was metal.  The foil encouraged conduction but discouraged convection.  My only conclusion for the reason it was not the worst is that the absence of convection with the foil resulted in a greater degree of heat being withheld compared to the convection that was occurring with the plastic wrap and newspaper.  Another thing I noticed on the surface of the newspaper was that it appeared to be wet on the outside, whereas the other materials were only damp on the inside when removed.  The newspaper obviously was allowing convection to occur, because water was traveling across the porous paper and then evaporating, which probably created a current that constantly cooled the water at a faster rate.  My explanation for the T-shirt being the best insulator is due to its thickness.  It did not have hardly any of the chemical properties to promote conduction by any means, and both convection and conduction must be less possible when the material in question is thicker.

            If I were conducting this lab at school, I would probably find some better insulators to work with, like rubber or parafilm.  It would also be nice to use a solid as the material generating the heat.  A hot dog fresh out a microwave would be a good way to show radiant energy in action.  Then, slicing the hot dog while it is still hot would show convection (the hot steam coming out).  Quickly wrapping the hot dog up in foil could then display conduction through the foil.

Guided Inquiry Experience from "Exploring the Physical World"

The question I selected for my guided inquiry experiment was whether a heavy pendulum or a light pendulum would come to rest more quickly. The first step of the inquiry process was planning the experiment. This involved obtaining equipment, which included three washers of varying mass, a long piece of string, a ruler for measuring the length of the pendulum, tape for marking the length on the string, a stopwatch, and a stopwatch reader (because the pendulum was being held by one hand and the weight needed to be released by the other). It also involved making note of all variables that needed to remain constant in order to get valid data for answering the question. I wanted to be sure that in comparing the time until rest for each mass that the length of the string would not change. The same stopwatch and manual timer was also used to avoid experimental error. I also wanted to run each mass three times to account for precision in the experiment. The final step of the planning process involved setting up a data table that was clear and concise for obtaining data for the task at hand.

Once the planning was completed, it was time to run the test. My results were as follows:

Washer	Time Passed Until 6” Pendulum Comes to Rest (s)
	Trial1	Trial 2	Trial 3	Average
Heavy	33.1	33.8	33.5	33.5
Medium	34.1	33.8	33.7	33.9
Light	33.6	33.5	33.2	33.4

From this data, the mass of the washer had no effect on the time it took for the pendulum to stop swinging. Just to verify this data further, I decided to run a second round of trials with the length of the string twice as long. I used the same washers for the same number of trials. My results were as follows:

Washer	Time Passed Until 12” Pendulum Comes to Rest (s)
	Trial1	Trial 2	Trial 3	Average
Heavy	52.1	51.8	50.9	51.6
Medium	51.4	51.2	50.8	51.1
Light	51.1	50.8	51.7	51.2

After viewing these results, it was clear to me that the mass of the weight on a pendulum was negligible when predicting the time the pendulum would go on swinging. By taking the time to complete a second round of experiments using a different length of string, another concept other than the initial question was accounted for. I found through guided inquiry that although mass has no effect on the time of pendulum swinging, the length of the pendulum string is proportional to the time it will take for the pendulum to come to rest. After researching the text further, I found that the equation that reflects this principle mathematically is

a_c= v²/r

where a_c is acceleration of pendulum weight, v is the velocity of the weight on the end of the pendulum, and r is the length of the pendulum string (Tillery, Enger, & Ross, 2008). The variable that is not in this equation is mass. Mass has no effect in this equation, but the length of the string does.

I was amazed at the precision of the results in this very basic experiment, especially since I was holding the pendulum by my hand as it was swinging. Any extra movement I made would throw off the true results for time, so plugging values into the equation mentioned above may be off a bit. The saving grace for this test was that the same type of error due to my movement was present to the same degree in each trial, leading to the precision of my values. To put it bluntly, my results were very precise, but they may be inaccurate, and one sure way to make the test more accurate would be to assemble a stationary fulcrum. This may lead to different stop times. However, the same result of mass being negligible should be apparent.

            I feel that any experience in which students formulate meaning based on direct observation of data is more rewarding than just giving them formulas to remember. I actually believe that searching for the formula that reflected the data received was part of the mystery that made the experience more enjoyable. This holds true for any inquiry experience. The unique aspect about today’s experience is that I had to develop the entire game plan for answering the question at hand. When a teacher provides only the question, and students must generate not only the results of a test, but the test itself, I believe that an increased level of thinking is involved that closely resembles the type of thinking that engineers must face when inventing a new process. One of the key functions of a K-12 STEM education is having the students “design investigations to gather data” (Lantz, 2009). The difficulties that an instructor may face with incorporating this method are lost time or safety concerns due to a general confusion as to what must be done to answer the question. It is always important then to remember that guided inquiry is “most successful when students have had numerous opportunities to learn and practice different ways to plan experiments and record data” (Banchi & Bell, 2008). Once students can become comfortable with these methods in a team environment, they are well on their way to becoming the next generation of engineers. Starting a lesson like this using amusement park rides is very exciting for children of all ages. I would have the students discuss whether the ride moves faster when it is completely filled with passengers or when it is empty. With all friction forces aside, the speeds should be the same, even though the force of the ride with the people is greater. You could also relate this fundamental property of mass and gravity to Galileo's experiment on the Leaning Tower of Pisa. These all provide either a background or an enrichment of the task at hand: to design the process. That is the most important goal for students when completing a guided inquiry lesson. It provides them with a sense of creativity and workmanship that can then be used to produce processes and answers to other questions in the future.

Banchi, H., & Bell, R. (2008). The many levels of inquiry. Science & Children, 46(2), 26–29.

Lantz, H. B. (2009). What should be the function of a K–12 STEM education? SEEN Magazine, 11(3).

Tillery, B. W., Enger, E. D., & Ross, F. C. (2008). Integrated science (4th ed.). New York: McGraw-Hill.

Flame Test Lesson Reflection

My lesson on flame tests was a huge success.  I used fireworks as an introductory attention grabber and asked the following questions:
1. What happens to atoms to cause them to release light?
2. Why do different fireworks burn different colors?
I allowed the students to discover the answer for themselves by guiding them through a series of flame tests and atomic spectra observation.  Followed by a sing-a-long about flame tests (I can't believe how well this went over with my juniors), I had my students conduct flame tests with unknowns. After successfully identifying the unkowns, they reflected on what they learned since their initial journal entries to the lesson opener. 

At the beginning of the experiment, their responses to the chemistry concepts were quite limited and incomplete.  However, as you can see from the attached student work samples, their conclusions reflected a growth in terminology and conceptual understanding.  I was very proud of them, and very pleased with myself.

Melting Icebergs Experiment Extended Questions

a.       What happens if the polar ice caps melt?

Based on the results from the experiment, it is clear that floating ice does not add extra volume to a body of water that it melts in.  Most of the ice is under the water already, and the density of ice is less than the density of water.  In other words, when ice melts, it actually takes up less space.  Therefore, I am fairly certain that the melting of any ice currently in the oceans will have little to no effect on sea level.  On the other hand, the ice currently on land does not contribute to the existing volume of water in the oceans.  Therefore, if much of this ice were to melt (like the Antarctic ice cap), water previously not present in the oceans would make its way there.  This would result in massive flooding along coastal areas, which would in turn cause many other disastrous side effects, mainly the spread of illness.  So to sum it all up, if the polar ice caps melt, flooding will likely occur due to the water running off the land into the sea (Antarctica or Greenland) rather than due to the already existing icebergs (which make up most of the northern ice cap).

b.      What other questions do you have about this Science Inquiry Experience?

Will the small tips of icebergs have any effect on the volume increase of the oceans?

What is the current projection rate as to how fast the water will rise?

What safeguards are being taken in preparation for this inevitable event?

Journal Entry Reflection on STEM Lesson Plan

Wow, what a process.  I was amazed at how many things there are to think about when designing a lesson plan for diverse learners.  I guess I have just taken it for granted that I am actually covering all those bases when I prepare my daily plans for my chemistry classes.  This assigment really made me appreciate the work that teachers are able to do.  When you take into consideration both the desired expectations and the simultaneous need to implement them fairly and equally to a wide variety of backgrounds, my first thought is how could this be practically possible.  However, with careful consideration and some ingenuity, it is absolutely amazing what teachers are capable of doing.   I feel the main thing to keep in mind when tailoring one's lessons is to think "variety".  Every lesson should be filled with a diverse set of teaching procedures and a diverse set of assessment procedures in order to allow all students a chance to shine in their own way.  Practically, this can be a challenge because I only have 90 minutes to work with every other day. 
The lesson I developed involved teaching the fundamentals of oxidation-reduction reactions by means of studying batteries.  It was a great topic as far as being relevant to the students, because I do not think there is one who has not listened to an i-pod, or used a flashlight, or rode in a car, among other things.  Nonetheless, in attempting to address many different forms of activity and assessment, my biggest fear for my lesson is that I would run out of time.  If I did run out of time, is it acceptable to make the lesson a two-day lesson, or would it lose its effectiveness based on the 5-E Learning Model being split over two days.  If time ends up being an issue with this lesson, I may want to rework the lesson to allow for two parts, each containing their own 5-E framework.  Speaking of the 5-E Model of learning, I have used it on many occasions.  I think it is the most useful model of delivering a quality science education, especially with the new emphasis on iquiry learning and STEM development.  It is a process that delivers the necessary content in a manner that is very meaningful to students while also leading students through the very act of being scientific in nature.  I love this model and will continue to use it to develop the best chemistry lessons possible.