Fall is the perfect time of year for you and your students to investigate plant pigments. If the curriculum sequence doesn’t fit, you can always squirrel away some data for later! PASCO’s Wireless Spectrometer (and its free Spectrometry software) makes it quick and painless to do data collection and get full spectrum scans. No more warm-up time, tedious wavelength adjustments, or students waiting in line!
Analyzing the absorption spectra is a popular lab activity that uses simple materials and can easily be extended into a student inquiry. PASCO’s biology team developed this new experiment to complement existing manuals and is available free to download.
Sample data showing the absorption spectra from several tree species (Tree of Heaven, Big Leaf Maple, and Black Oak leaves)
Many biology courses at every level start the year studying enzymes, since they are integral to so many biological processes. No matter what your preferred enzyme and substrate, sensors can help you get more data, and better data, faster. As you can see, we like to catalyze with catalase since it’s widely available (in nearly all living things) and easy to process for lab use.
Figure 1. Each setup uses a 15 mm test tube, #1 1-hole stopper, 3 mL of 3% H2O2, and 1 mL of yeast suspension in a water bath at a set temperature.
Figure 2. SPARKvue monitors bath temperature while recording pressure data for each reaction.
Table 1. Rate of Reaction for Yeast and Hydrogen Peroxide
Figure 3. Graph of Reaction Rate vs Temperature
With more data it’s possible to produce meaningful descriptive statistics with your students. This supports students’ math literacy and is useful to identify runs/groups that are outliers from the class data. While these outliers are often procedural errors, they can provide a useful springboard to inquiry. Ask students to determine why the group’s results differ. Are their results reproducible? If time allows, they can explore additional variables that can add to their understanding of protein structure, enzyme reactions, and even evolution.
The data above was produced using the Wireless Pressure Sensor. The protocol is the same with the Oxygen Gas Sensor; download the lab for your preferred approach.
Ocean acidification is a byproduct of increasing atmospheric CO2 levels around the globe, which is also causing climate changes. This global phenomenon can be difficult conceptually for students, but it is easy to model using sensors.
Here’s a quick video using the Wireless CO2 and Wireless pH sensors:
Using a few simple materials, this quickly demonstrates to students what impact gaseous CO2 can have on the pH of water as it dissolves. Ask students to consider the limitations of this model: How does it differ from earth systems? How could the model be improved?
Looking to extend this into a student lab? We’ve got an inquiry lab where students can act as the CO2 sources and monitor pH with a sensor, while learning more about the chemistry behind ocean acidification.
Catalyze student learning in AP Biology through an investigation of enzyme activity. By using a PASCO Wireless Spectrometer students can monitor the reaction in real-time and build a more robust data set.
Students can investigate the decomposition of hydrogen peroxide into water and oxygen by using peroxidase (found in filtered turnip extract). With a small amount of Guaiacol in solution the reaction can be easily monitored in the Wireless Spectrometer because it changes color as it oxidizes.
After creating a blank and calibrating the Wireless Spectrometer on the Analyze Solution tab, select the target analysis wavelength of 470nm.
Figure 1. Setting the analysis wavelength in the Spectrometer Software
Students can then go to the Time tab to monitor the reaction at 470nm. Prepare the reaction in a standard cuvette by adding the substrate (H2O2), pH buffer, and Guaiacol. Once the enzyme extract is added the reaction proceeds quickly, so make sure to test the reaction before the lab and dilute the enzyme extract if needed.
Figure 2. Monitor the reaction in real time before analyzing and comparing runs from various trial groups
After establishing a baseline, the rest is inquiry! By changing the pH buffer, temperature, or enzyme and substrate concentrations students can quickly explore the reaction and identify the optimal conditions for turnip peroxidase. Data can be analyzed in the software to determine the rate of reaction or exported for aggregation and further analysis. This is a great lab to introduce or reinforce concepts around protein structure and specific nature of the enzyme-substrate complex. Students can also compare the catalyzed and uncatalyzed reaction to see how the energy of activation is lowered by these (seemingly magic) biological molecules!
Figure 3. Sample data from investigation of Peroxidase reaction at pH 2, 4, 7, 10, 12
Making the leap from circuit diagrams to functioning circuits has never been so clear or intuitive. Circuits can be easily built and tested enticing students to more thoroughly explore the behavior of electricity. Your students will no longer be frustrated trying to trace out the electrical pathway through a nest of wires.
Supports inquiry learning – circuits can be easily modified and be quickly swapped out and rearranged
Compatible with both traditional and computer based labs – works with PASCO’s sensors as well as traditional Volt and Ammeters
Classroom management is a breeze – Storage is made simple with the included
Grattenels case and nesting trays
The 8 cm by 8 cm modules ensure that all students in a group can clearly see the completed circuit
Physical Components (resistors, batteries, switches, etc.) with identifying electronic symbols are visible on the surface of the modules
At a glance errors in a circuit can be quickly found without checking each connection
The Basic Kit includes enough modules to do 5 basic experiments:
Batteries & Bulbs Circuits
Electric Power & Energy
The Advanced Kit includes the Wireless Current & Voltage Sensors and modules for 7 additional experiments:
We were thrilled to attend this year’s NSTA national conference in Los Angeles.
Our first destination was the exhibit hall where PASCO had a very lively booth with several interactive displays. By far the biggest hit was the ‘Match Graph’ challenge with a super-sized Smart Cart. Who knew that learning could be this much fun! Check out the video to see my less than stellar attempt.
PASCO’s booth was fun, however, the real action was in the teacher facilitated workshops. In total PASCO had 20 unique hands-on sessions that were over flowing with enthusiastic teachers. Time didn’t allow us to see all the sessions, but we did manage to squeeze our way into a very energetic session on the new Modular Circuit Kits. Teachers had a great time ignoring instructions and spent most of the session designing their own unique circuits – obviously investigative learning is not just for students.
We were also fortunate enough to get a seat at PASCO’s workshop session on climate change. The session featured several hands-on modeling activities, including an investigation where teachers used the Wireless pH sensor to monitor the mitigating effects of natural buffers on acid rain. The biggest hit of the session was seeing PASCO’s new Wireless Carbon Dioxide sensor in action. Teachers were excited to discover that a reliable, practical and affordable way to measure CO2 has finally arrived.
Over the next week we’ll share some more videos on our adventures at the conference.
Students often struggle understanding pH. While we can tell them that it is a logarithmic function, students are more likely to associate “logs” with a calculator button or a piece of wood. So how do we get them to understand what the pH scale really means? Look for a lesson, instead of a pot of gold, at the end of a rainbow.
Let’s start with the acids. First have the students pour 10 mL of 0.1 M HCl into a test tube. Using graduated cylinders and pipets they can add 1 mL of that solution to another test tube with 9 mL of water making a 0.1 M solution. They should repeat the process of taking 1 mL of the previous solution and adding 9 mL of water until there are 5 solutions. They won’t know it, but they just performed a serial dilution. Now they can add some universal indictor to the solutions for a splash of colour.
Indicators are nice, but they really are just an indicator. In this case the indictor was not able to distinguish between the first four test tubes. (Note to self: get some new universal indicator!). Since the true colors aren’t shining through, it’s important to remember that to really understand pH, your students need to take actual pH measurements.
Now comes the pHun part! After recording the data for the solutions, it is important for students to try to make some meaning out of those measurements. Time to dust off those concentration calculation skills. They should be able to calculate the concentration, and write the concentration of the acids in scientific notation.
No need to travel somewhere over the rainbow, all your students need now are some good guiding questions and they should see that pH is primarily based on the negative exponent of the concentration of H+. With this understanding, pH=-log[H+] can be something more powerful than just a formula to plug and chug in calculator.
You can even extend this activity to pOH and its relationship to pH if you drop the base. Following the same procedure, students can perform a serial dilution starting with a 0.1 M NaOH solution.
After this colourful and engaging activity with the Wireless pH sensor and some fresh universal indicator, your students will be able to find the rainbow connection: a better understanding of the pH scale, what it means and how it’s measured.
The ability to easily and affordably measure CO2 levels is great news for Biology and Environmental Science teachers.
PASCO’s new Wireless CO2 Sensor communicates directly with a wide range of Bluetooth equipped computers without requiring an expensive interface.
Ambient environmental Carbon Dioxide levels are typically very low. This means any experimental changes to CO2 levels tend to be significant in percentage terms providing convincing and reliable evidence of the phenomenon being studied.
Investigations based on the wireless CO2 sensors are easy to setup and they work.
Other opportunities for CO2 investigations include: