Technology Project #3 Vernier pH Sensor

Technology Project #3: pH Sensor Vernier

 Vernier produces numerous types of sensors and equipment to aid in science and more importantly science education. The equipment provided by Vernier has many uses in a variety of subject areas such as chemistry, biology, physics, and middle school classes. The sensor analyzed in this particular blog post is the pH sensor. The pH sensor is a Ag-AgCl combination electrode with a pH range of 0 to 14.  Although I am quite familiar with pH probes due to my chemistry background, I am interested in the higher quality of the sensors and advances they now have. This pH sensor adds the option of automated data collection, graphing, and data analysis. The pH sensor comes calibrated but can be re-calibrated buy purchasing the appropriate solutions. If the pH sensor continues to read around 6.7 while the sensor is in a 7.0 solution the sensor can be "shocked" to help fix the problem. Reference the user guide for this option. 

Links to pictures of technology artifacts.
 The following are links to the user guide for the pH sensor and images of the pH sensors. There is a web page that is designated for engineering education with Vernier technology that gives videos for advanced uses of the pH sensors. The sensor does cost around $79 not including the pH storage solutions and solutions for calibration of sensor. Without access to a laboratory I am unable to work hands on with the sensor but have worked with older styled pH sensors in educational career. I did my exploring of the technology through the user guide and searches on how the Vernier pH sensor has been implemented into laboratory uses.


Description of and rationale for how the technology might be used with and preferably by students.
 The typical projects I would have the students do with the pH sensor would be those that allow the student to monitor the pH of the solution and to analyze results of an experiment to determine molar concentrations. Other types of projects could include more environmental science activities such as water  sampling and analyzing. The pH testing of water samples or other common (everyday) samples will formulate a more concrete relationship between chemistry and everyday life. Especially in introductory science education the terms acidity, basicity, and pH may be abstract to the students. The reality that pH is why we as humans can stay alive and digest food and move for that matter is a concept worth exploring in detail. With the use of the pH sensor more adequate results and experiments can be conducted to give insight into the relationship between pH and how it impacts everything around us. Through numerous types of pH experiments, activities, and investigations the students will be able to actively engage in making the connections between the concept and reality. The students can get creative by deciding what types of solutions to test and go further to adjust the pH and see how it impacts the sample and reflect on how it would alter where the sample came from. Reflecting even further if the adjusted pH were to occur in real life what type of solution may be implemented to help regain the functional pH. Through all theses projects the concrete concept would be applied. Students would be doing hands on experiments and activities with real objects using the pH sensors to better understand the concepts of acidity, basicity, and pH and their impact on life. Throughout experiments and activities the students would work in groups bouncing off ideas and thoughts about what is taking place. The interaction amongst students in group work helps those who do understand a concept (i.e. pH) teach and help those who do not.
  An in depth project I would use the pH sensor would be in determining the molar concentration of two acidic solutions by conducting titrations with a base of known concentration (titration). The experiment would require students to perform microscale acid-base titrations while monitoring the pH (using the pH sensor). To carry-out the calculations to determine the concentration of the acids students would benefit from the more precise measurements obtained from the pH sensor opposed to older pH sensors that take a fluctuating reading or the use of pH paper. The error reduced pH sensor readings will give students the ability to calculate acid (especially weak) concentrations more accurately. Thus, instead of just doing homework problems with made up amounts and results the students would carry-out a hands on experiment that would yield high quality read outs in order to relate the action to the calculations performed.




Consideration of struggles for implementation (student, systematic, and/or hardware).
  The struggles of implementation would be that the sensor would need a supporting program to read the data. The programs accepted include LoggerPro, LabQuest, LabPro, Go!, EasyLink, Sensor DAQ, and CBL2. The purchase of one of these programs would be required. As mentioned previously, the pH sensor does cost around $79 a piece not including the cost of a stand and storage and calibrating solutions. The information can be obtained from a stand alone type of program but then in order to print or analyze must be imported to a computer or manually recorded. Also, the sensor is shipped calibrated but may require re-calibration after time. The pH sensor may be broken if left out to dry. To avoid the drying out of the sensor it needs to stay in a storage solution (preferably pH 4.0 KCl), like almost all other pH sensors. As with many other forms of technology there may be glitches in a sensors performance but Vernier offers support for their products and  may solve the issue. Finally, a holder may be required so that the sensor sits in the solution well to obtain readings. Emerging the sensor handle in the solution will break the sensor for the handle is not water proof.


Consideration of the biases and trade-offs of the technology.
Some biases and trade-offs for the use of pH sensors and the associated automated data collection would be the lack of relationship between preparing for the data collection and what is occurring during the data collection. This intellectual relationship may be lost in automated data collection. For example, when a student is carrying out a microscale acid-base titration using a color indicator the student is able to see (concrete) when the color changes instantly when the solution being titrated becomes acidic (if base), or basic (if acid). The drastic and quick color change is a concrete way to show students when the endpoint has been reached. However, the trade-off to the pH sensor for benefiting the learning process is that the teacher can explain that with the pH sensor the readings can show a more precise equivalence point opposed to the endpoint. The endpoint achieved by color pH indicators is when the solution has gone slightly past the equivalence point and is more basic or acidic than the equivalence point. The equivalence point (equal concentrations of OH- and H+) can be explored and explained using the pH sensor and program to read the precise readings.
 Another bias or trade-off would be that the students, if using a program to collect data that gives a graph reading simultaneously, would lose the practice graphing a titration. However, graphing of a titration is near impossible without the readings from a pH sensor. The pH sensor could initially be used only for the readings and the graphing and analysis of the data be carried out by the students. Having the precise pH readings and automated data collection and graphing would be beneficial for weak acid and base analysis where the concept becomes more difficult for students to understand. The automation will allow for the students to observe the outcome and grasp the idea before becoming frustrated. To accompany the use of the pH sensor and automated data collection and graphing the students could use pH indicators to observe the slower color change that occurs when titrating a weak acid or base. But for calculation purposes the precise automated values and collection would benefit the students in obtaining realistic answers to the calculation of an unknown weak acid or base. In conclusion, the pH sensor allows for precise readings and the drastic change can be seen as the pH value jumps or drops quickly. However, the use of pH indicators while using the pH sensor and or separately will allow for another way to observe the endpoint of a titration. If the students are not doing a titration in the experiment or activity and are using it to test a sample of water obtained from a pond or other source the use of a pH sensor with automated readings would be beneficial for the students to detect the pH without having to determine the pH from pH paper or by titrating it with an indicator and carrying out calculations. The quick reading of a sample solution will save the students a great deal of frustration and allow for the analysis of numerous samples.


Explanation of how the project meets the selected teacher standard and student standards.
The implementation of the pH sensor technology meets the ISTE second and third teaching standards. The second teacher standard states that the teachers design, develop, and evaluate authentic learning experiences and assessment incorporating contemporary tools and resources to maximize content learning in context and to develop the knowledge, skills, and attitudes. The use of the pH sensor and its associated activities and experiments allow for the teacher, as well as the students, to develop activities to investigate the scientific concepts that can be explored using the digital technology. The experiments may require calculations and submission of results to which the teacher can evaluate how well the student performed the experiment and how well they understand what was happening and why they did what they did. The teacher can evaluate how the student's work reflects what they know about the pH, acid, and base concepts related to the activity. The teacher can use activities that use the pH sensor and equipment to maximize the content learning with regards to acids, bases, and pH. This is done by not only having the students use pH indicators but associating real values with the experiment and discussing what the values mean and how to calculate or predict what the pH value should read when a known amount of acid and base is added.
 The third ISTE standard states that teachers exhibit knowledge, skills, and work processes representative of an innovative professional in a global and digital society. The use of the pH sensor and data collecting equipment during experiments demonstrates the model of digital-age work and learning. The students are learning and gaining hands-on experience with types of equipment utilized in scientific laboratories. The teacher can facilitate experiences with digital technology that will increase the accuracy of results and help them learn about the concepts using the up-to-date digital technology. The teacher can facilitate a professional type scientific laboratory experiment for the students to increase their degree of professional results and organization given by the programs they will be working with. In the end, the students are able to carry out practices similar to what the professional scientists do that builds on the basics with the use of digital and advanced technology, in addition to the teachers instruction and knowledge of available technology and activities.



Cite and evaluate educational research related to the technology use. 
 The article I read was titled Science in the Palms of Their Hands and it was a broad based article about the technologies that improve science education. The use of pH sensors was discussed but also the overall conclusions demonstrate why improved technology is beneficially for the intellectual advancement of students. The research suggested that the use of sensors and probes (technology) in the science classroom is motivating to the students. The use of technology motivates them to want to do more science, which is a main goal because science is doing. Researchers found that doing activities that use the technology help kids develop critical capacities in evaluating scientific measurements and knowledge, make stronger connections to the scientific concepts underlying their investigations, and develop deeper understandings of the relationship between science and technology. The article also went beyond to discuss how students should develop their own technologies to carry out tasks. That way the students have a better understanding for what the technology they are using truly does.

Reference: Science in the Palms of Their Hands. Elliot Soloway, Wayne Grant, Robert Tinker, Jeremy Roschelle, Mike Mills, Mitchell Resnick, Robbie Berg, and Michael Eisenber. Communications of the ACM. August 1999. Vol. 42, No. 8.