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## Mole Day

It’s that time of year again. Chemistry teachers everywhere are dusting of their pun-ny jokes and creating mole-themed, activities and treats to celebrate National Mole Day in commemoration of Avogadro’s number (6.02 x 1023). Mole Day is celebrated starting at 6:02 am on October 23rd. How will we be celebrating? With chips and Guaca-mole, of course!

As we introduce the topic to students we typically start with something they already know. A mole, like a dozen, is a way of counting things. It just so happens that a mole is a really large number. While 1 dozen equals 12, 1 mole equals 6.02 x 1023. This number has to be very large because the particles that we deal with in chemistry happen to be very, very small (or sm-ole… the bad jokes keep on coming).

To give students a mole-ecular perspective of those tiny particles, you can use a modeling kit.

At this point in the year it is important for students to understand the basics of chemical formulas. The model kit gives them something to see and touch as they learn that subscripts in a formula represent the number of atoms that are bonded in the compound.

In addition to formulas, the model kit can be useful in calculating molar mass. Since each different colored atom represents a different molar mass, students can just take their model and add up all the masses of all the atoms that they see! In the case of water, the oxygen is 16 grams per mole and each hydrogen is 1 gram per mole. In total, there are 18 grams for every one mole of water molecules.

So how do chemists relate these tiny particles to something that they can measure, like grams? Moles to the rescue! Avogadro’s number (the number of particles in one mole) and molar mass (the amount of grams in one mole) both meet in the middle at … moles.

Moles are central to counting particles in chemistry. Using Avogadro’s number and the molar mass of water, we know that there are 6.02 x 1023 molecules in graduated cylinder that contains 18 grams of water.

Model kits can be great tools in helping students visually and kinesthetically learn about chemical formulas. They become actively engaged in the learning process as they discover the meaning and value of subscripts, molar masses and, of course, Avogadro’s number. And as students gain a better understanding of these concepts the real fun begins— they start to really understand your science humor! “Oh no! I’ve spilled water on my book!”

Happy Mole Day!

## Experiment: How Hard is Your Tap Water?

Students use conductometric titration and gravimetry to determine how much calcium carbonate is in a sample of tap water.

This lab is an introduction to methodological comparisons. Percent error is calculated for both gravimetry and titration. Samples of tap water from various locales are concentrated and analyzed for calcium content.

## Student Files

• 03_ACI_How_Hard_Is_Your_Tap_Water_S.docx
• 03_ACI_How_Hard_Is_Your_Tap_Water_S.pdf

## Standards Correlations

• IB Topics
• 1.4
• AP Topics
• SPQ-1.A; SPQ-2.A; TRA-1.C; SPQ-3.C; SPQ-4.A

## Featured Equipment

• Wireless Drop Counter
• Use the new Wireless Drop Counter for more efficient and accurate titration data. Conducting a titration has never been easier!
• Wireless Conductivity Sensor
• This waterproof sensor connects via Bluetooth® to measure both conductivity (ionic content in solution) and total dissolved solids.

This experiment can also be run with previous versions of PASCO sensors.

## Seven Great Experiments Using the Wireless CO2 Sensor

Measuring Carbon Dioxide (CO2) has many applications in the classroom and with the latest advances in technology is easier and more affordable than ever before. Here’s a quick look at some of the cool things you can do with the new Wireless CO2 Sensor!

### 1. Monitor Air Quality

An engaging way to introduce students to the sensor is to use the “closed” environment that you already have access to – your classroom or lab. This is also a great opportunity to use the data logging capabilities of the sensor. Find a central place in the room to place the sensor, ideally suspended above students heads where they can’t exhale onto the sensor. Place the sensor into logging mode, and collect 8-10hrs of data (Figure 1a). Depending on the student density in your room, HVAC, how closed the environment is, you should be able to see fluctuations in the CO2 levels that correspond to the class schedule because all of those students are busy breaking down glucose and producing CO2.

###### Figure 1a. Data from sensor logging over a school day.

Students can repeat this test in other locations such as the cafeteria, greenhouse, bathrooms, etc. While there are conflicting standards generally a CO2 concentration of <1,000ppm is desirable and >3,500ppm people will begin to experience physiological effects. Many modern HVAC systems even have their own sensors that will cycle the air to maintain CO2 levels <1,500ppm you can probably tell from the data if you your school or lab has one!

### 2. Investigate Cellular Respiration

With the included sample bottle students’ can use invertebrates, germinating seeds, or other small organisms to quickly collect respiration data. Variation in environmental factors like light or temperature provide easy extensions as well as germination time, species comparisons, body mass, activity level, etc.

###### Figure 2. Respiration of Germinating Seeds

Extending this setup the sensor can be used with bacterial or yeast solutions, even aquatic species by measuring the gas concentration in the headspace of the container.

###### Figure 3. Headspace Measurement above a liquid

While a smaller chamber will yield faster results (gas concentration will change faster) sometimes a bigger chamber is needed to study larger organisms or when modeling ecosystems. This is where the wireless design is particularly helpful, the sensor can easily be placed inside any container along with the organism being studied – without any modifications. If you need to run the sensor for longer than about 18hrs, connect it to an external USB power pack or source and the sensor can continue working.

### 3. Investigate Photosynthesis

To get great photosynthesis data you just need a fresh dark green leaf, the sensor, and the sample bottle. Put the leaf in the bottle, cap it with the sensor and start data collection! Using the sample bottle and a fresh leaf ensures a quick response – data runs of 5-10min! Light vs. Dark and wavelength are simple and relevant manipulations for students to conduct.

###### Figure 5. Photosynthesis using a single Epipremnum sp. Leaf with no filter, blue filter, red, and green applied. Plants exposed to full spectrum CFL bulb for 10min runs.

 Test CO2 Rate (ppm/min) Light (no filter) -17 Blue Filter -7 Red Filter -9 Green Filter -12 Dark (tinfoil wrapped) +32
###### Table 1. Summary of change in rate found from each run of data.

And more ideas (than I have time to test): Light intensity, impact of temperature, herbivory, time of day, herbicide impact, stomata density, C3/C4/CAM Plant comparison, CO2 Concentration

### 4. Measure Carbon Flux in the Field

In some cases lab experiments aren’t feasible or desirable. It’s easy to take the sensor into the field using a cut bottle, bell jar, or plastic bag to isolate a plant or patch of soil for analysis without disturbing the environment. Firmly press the container into the substrate to create a tight seal and begin collecting data. Students can easily compare different ecosystems to determine if they are a net carbon producer or consumer under conditions. This technique can be repeated in different conditions, times of the day or year to compare results.

###### Figure 6. Cut bottle with sensor place over patch of turf

This same technique combined with the concept of measuring a headspace over a liquid to determine the gas exchange can be used to monitor carbon flux in an aquatic ecosystem. Securing the sensor with a float (or to a fix object) to protect it creates the airspace needed to measure above the water. Collect data for the day to see how a body of water is exchanging carbon with the atmosphere.

### 5. Monitor Respiration of Soil Microbes and Decomposers

To streamline the sample collection and measurement of soil samples students can use a section of PVC to collect a consistent volume of substrate and make the measurement in the same chamber. A 6-8in (15-20cm) section of pipe with an inner diameter of ~1.125” (3cm) can be easily pounded into the ground a specified depth to collect the sample. Seal the end of the pipe with some parafilm or plastic wrap and collect the data.

###### Figure 8. Sensor in PVC tube with marking for soil sample depth, clear PVC used to demonstrate

Data collection can take place in the field or lab and is easily extended for inquiry. Students can treat the samples with pH buffers, water, drying, salt, pesticides, or other chemicals of interest to determine the impact on microbe respiration.

### 6. Measure Human Respiration

Using a drinking straw and a 1gal (4L) ziplock® bag its easy to capture human respiration data. Here’s a video comparing breath hold time. This same procedure can be used to test other variables, before and after exercise, time of day, etc.

### 7. Dissolved CO2 in situ

With Dissolved CO2 Sleeve students can monitor CO2 in an aquatic environment. The Teflon® material is permeable to CO2 molecules but not to water, creating a much smaller headspace around the sensor with a better response time. While the CO2 is not dissolved when its measured this approach has been validated and tracks with other indicators such as pH (Johnson et al 2010). This approach works well in the field and in the lab for photosynthesis and respiration experiments. Below is a picture and some data we collected during betta testing!

Reference:
Johnson, M. S., Billett, M. F., Dinsmore, K. J., Wallin, M. , Dyson, K. E. and Jassal, R. S. (2010), Direct and continuous measurement of dissolved carbon dioxide in freshwater aquatic systems – method and applications. Ecohydrol., 3: 68-78. doi:10.1002/eco.95

## Exploring 2-Dimentional Motion and Vectors with Capstone’s Video Analysis Feature

Capstone includes a very powerful video analysis feature which can be used for comprehensive analysis of moving objects as well as to improve understanding.  Short video clips from your smartphone can be easily imported and analysed with a range of tools.  The movement of objects with a high contrast to a uniform background can be automatically tracked by the software.

A ball will be thrown in a parabolic arc and various tools will be used to analyze the motion.  Note that the vertical and horizontal axes have been marked and a distance of 4.00 m has been measured.  This will enable the software to translate from pixels to m:

As part of the analysis, the position of the ball in each frame is marked and the result is as shown below:

It is now possible to have the software generate various graphs such as position vs time and velocity vs time.

A graph of vertical position vs time is as shown below:

A graph of horizontal position vs time yields the following:

A graph of the vertical component of velocity vs time yields the following result:

Capstone also includes tools that improve understanding.  For example, in the screen below, the vertical and horizontal components of velocity are shown for the ball as it flies through the air.

To make the display less cluttered and less confusing it is possible to mark the vectors at an interval other than every frame.  Below the vectors are shown every third frame:

It is also possible to have a single vertical vector and a single horizontal vector appear and move with the ball as it goes through the air.

It is also possible to show the acceleration vector as shown below:

The fact that a few vectors do not point directly down is likely due to minor errors made when marking the position of the ball in various frames with a mouse.

## PASCO Day of Physics – July 24, 2020

Session 1

Session 2

Session 3

Session 4

Session 5: Cool Physics Demos

• Coupled Oscillators Smart Cart (FFT) & Friction Block+PAScar
• Inertia Wands
• Atmospheric pressure Demos
• Polarizer Demo / Color Mixer / Color Mixer Accessory
• Genecon Hand Crank Generator Coil & cow magnet on a spring
• Eddy Currents – magnetic braking
• Mirror pendulum demo

## SPARKVUE – A resource for planning lessons during the pandemic!

With SPARKvue it is possible for teachers to collect data and steam the data to students in real time via a student device also running SPARKvue. This is possible if each device has SPARKvue loaded on it and is connected to WiFi – even if the devices are located many kms apart. So a teacher could schedule a zoom session with his/her students. Students could use a computer for this activity. The teacher could then carry out an activity on another device loaded with SPARKvue and stream this to students who would have a second device such as a tablet, chromebook or smart phone to receive the data. After using the zoom platform for some preliminary discussion the teacher could then turn control of the data over to each individual student and this student could then use all of the tools available to him/her in SPARKvue to carry out the analysis.

Has it been difficult for you to plan lessons for your students that would result in meaningful learning as they tackled them at home?

SPARKvue data collection software can be a great help here for several reasons:

•  SPARKvue will run on a great variety of devices including smart phones, tablets, chromebooks, and computers. It is free for all of these devices except for computers, for which a license must be purchased.
• The appearance and function of SPARKvue software is virtually identical ascross platforms.
• An activity planned and carried out and saved on one device such as a tablet can be opened in another device such as a chromebook.
• All of Pasco’s sensors can be used with any of these devices

• Unlike the software of some of our competitors, it is possible to generate a number of pages in SPARKvue (actually there is no limit). This makes it possible to use a number of the displays available in SPARKvue such as a digital picture, a video clip, a graph, a table, a meter, a digital display, an assessment, a text box, and blockly coding.
• A teacher could design and carry out an activity where most of the analysis is left for the student to complete. For example the sequence of pages could look as follows:
• The opening page is a title page and gives a brief description of the task to be completed
• Page 2 shows a digital photograph of the setup to be used
• Page 3 contains a short video clip in which the teacher gives a brief explanation or where a specific technique is demonstrated – eg how to connect a pressure sensor to a syringe (for a Boyle’s Law activity).
• Page 4 is a text box which informs students that a data run has been collected by the teacher and the following pages will instruct them how to analyze the results. For example on page 5 the page is split into two parts with the larger part on the left. Students are asked to generate a graph of the data. On the right side there are a number of questions which students must answer by analyzing the graph. This means that the students will have to know how to use the analysis tools found as part of the graph display.
• On page 6 students could find another split page. Suppose a motion sensor was used to collect data. On the left side students could be asked to plot a graph of kinetic energy vs time. This means they would have to know how to use the calculator in SPARKvue. On the right side of the page there could be a number of questions relating to this graph.
• SPARKvue can collect data from more than one sensor at a time. For example, an activity could be carried out in which the pH and temperature of a sample of orange juice is measured when AlkaSeltzer is added. Students could be asked to generate a graph showing both the temperature and pH of the juice as the reaction proceeds and then be asked a series of questions on this reaction.
• As can be seen from the examples above SPARKvue can be used to carry out extensive analysis of collected data.

## Wireless Smart Cart, Wireless Spectrometer, and Wireless Weather Sensor

We are pleased to announce that PASCO has been awarded three “Best of Show” awards! More than two thousand science and STEM educators participated in the first Science Educators’ Best of Show™ Awards by casting their votes for products that they felt impacted science learning. We are honored to have our products recognized in a competition designed by science educators for science educators. You can check out the winners below!

Category: Best New Technology Innovation for STEM
Winner: PASCO’s Wireless Smart Cart and Accessories
When physics educators combine the PASCO Wireless Smart Cart with the available accessories, they have a complete platform for demonstrating some of the toughest topics in mechanics. The Smart Cart’s ease of use and extensive capabilities allow students to perform their mechanics labs to a high degree of accuracy and repeatability. With sensors for position, velocity, acceleration, force, and rotation, the Wireless Smart Cart relays live data to help students test their understanding of mechanics in real time.

The wireless nature of the PASCO Wireless Smart Cart and Accessories is a definite improvement [over traditional systems]. The removal of wires needed to connect to an external interface makes data more accurate and opens up opportunity for more innovative experimentation. The accessories for the carts also are very innovative and extend the scope of investigation.

— Science Educators’ Best of Show Judge

Category: Best Tried & True Technology Teaching and Learning: Chemistry
Winner: The Wireless Spectrometer and Spectrometry software
With measurements for emission spectra, intensity, absorbance, transmittance, and fluorescence, the Wireless Spectrometer is surely more powerful than its size suggests. Its visual, user-centered design makes it easy for educators and leaners of all levels to integrate spectrometry into their learning. The key is PASCO’s Spectrometry software, which allows students to quickly generate standard curves, make comparisons, and analyze their results using its visual absorbance display. When combined, the Wireless Spectrometer and Spectrometry software provide educators with a classroom-friendly spectrometry solution that can be applied to a wide variety of chemistry topics.

This device provides advanced analysis potential of spectrum analysis for chemistry, environmental and physics classes that is quite rare for high school classes to experience. The data collection is quick and thorough with excellent software for analysis on many devices. Use of this device and software will enhance learning in many science courses.

— Science Educators’ Best of Show Judge

Category: Best Tried & True Technology Teaching and Learning: Environmental Science
Winner: The Wireless Weather Sensor and SPARKvue software
With more than nineteen different measurements, including GPS, the Wireless Weather Sensor supports real-world environmental investigations that relate phenomena to data collection and analysis within SPARKvue. Together, the Wireless Weather Sensor and weather features within SPARKvue create a coherent solution for performing both long-term and short-term environmental inquiry at any science level. The Weather Dashboard within SPARKvue intuitively displays live and logged data, while SPARKvue’s ArcView GIS mapping integration supports geospatial investigations and analysis.

This sensor would provide extra opportunities for data collection in environmental science. It does offer a variety of options for experimental situations-19 in all. Experiments can be of short duration or long term. The weather vane is mentioned as an extra device to enhance data collection.

— Science Educators’ Best of Show Judge

## Who Discovered Spectroscopy?

Similar to many scientific concepts, spectroscopy developed as a result of the cumulative work of many scientists over many decades. Generally, Sir Isaac Newton is credited with the discovery of spectroscopy, but his work wouldn’t have been possible without the discoveries made by others before him. Newton’s optics experiments, which were conducted from 1666 to 1672, were built on foundations created by Athanasius Kircher (1646), Jan Marek Marci (1648), Robert Boyle (1664), and Francesco Maria Grimaldi (1665). In his theoretical explanation, “Optics,” Newton described prism experiments that split white light into colored components, which he named the “spectrum.” Newton’s prism experiments were pivotal in the discovery of spectroscopy, but the first spectrometer wasn’t created until 1802 when William Hyde Wollaston improved upon Newton’s model.

William Hyde Wollaston’s spectrometer included a lens that focused the Sun’s spectrum on a screen. He quickly noticed that the spectrum was missing sections of color. Even more troublesome, the gaps were inconsistent. Wollaston claimed these lines to be natural boundaries between the colors, but this hypothesis was later corrected by Joseph von Fraunhofer in 1815.

Joseph von Fraunhofer’s experiments replaced Newton’s prism with a diffraction grating to serve as the source of wavelength dispersion. Based on the theories of light interference developed by François Arago, Augustin-Jean Fresnel, and Thomas Young, Fraunhofer’s experiments featured an improved spectral resolution and demonstrated the effect of light passing through a single rectangular slit, two slits, and multiple, closely spaced slits. Fraunhofer’s experiments allowed him to quantify the dispersed wavelengths created by his diffraction grating. Today, the dark bands Fraunhofer observed and their specific wavelengths are still referred to as Fraunhofer lines.

Throughout the mid 1800’s, scientists began to make important connections between emission spectra and absorption and emission lines. Among these scientists were Swedish physicist Anders Jonas Ångström, George Stokes, David Atler, and William Thomson (Kelvin). In the 1860’s, Bunsen and Kirchhoff discovered that Fraunhofer lines correspond to emission spectral lines observed in laboratory light sources. Using systematic observations and detailed spectral examinations, they became the first to establish links between chemical elements and their unique spectral patterns.

It took many decades and more than a dozen scientists for spectroscopy to be well understood, and most modern models weren’t developed until the 1900’s. Today, there are physicists, biologists, and chemists using spectroscopy in their day-to-day lives. For more information, visit our in-depth guide, What is Spectroscopy? or check out our other blog post, “What is the Difference Between Spectroscopy and Microscopy?”

## 2020 Skills Sheridan Competition

Sheridan College (Davis Campus) conducted their 3rd annual Skills Competition on March 4th, 2020, a day dedicated to recognize and celebrate the accomplishments of the students from various programs within the Faculty of Applied Science and Technology. Previously, professors selected their top students to compete in the Skills Ontario competition but with Sheridan’s new Skills Trade Centre, a more engaging way to select the students was brought forward.

Participants choose one stream and put their skill and knowledge to the test while engaging in a friendly competition with their peers. Some of the various streams included electrical engineering, information technology, precision machining, computer engineering, media management, web design, and welding.

AYVA was proud to be a sponsor for this years’ event. It was an honour to be able to witness the extraordinary projects presented by the students.

At the end the competitions, students and sponsors were gathered together for the presentation of the awards.

First, second and third place medals (which are made by the skills trade facility!) are awarded to the students.

Congratulations to all the winners and participants in this year’s competition!

## Using the PASCO Smart Cart to Teach the Right-Hand Rule

We high school physics teachers tend to associate the right-hand rules with electromagnetism. As a student, my first encounter with a right-hand rule was when I was introduced to the magnetic field produced by the electric current in a long, straight wire: if you point the thumb of your right hand in the direction of the conventional current and imagine grasping the wire with your hand, your fingers wrap around the wire in a way that is analogous to the magnetic field that circulates around the wire.

I only later discovered that this same rule can be applied to rotational quantities such as angular velocity and angular momentum. The topic of rotation has become more important in AP physics when the program was updated from the older Physics B program. Strictly speaking, AP Physics 1 does not include the use of the right hand rule for rotation, but I have found that introducing it actually helps solidify student understanding of angular vectors.

Describing the direction of rotation as being clockwise or counterclockwise is helpful only if all parties involved have a common point of view, which is ideally along the axis of rotation. As with left and right, clockwise and counterclockwise depend on your point of view. This is why it is often preferable to describe translational motion in terms of north, south, east, west, up, and down, or with respect to a defined x-y-z coordinate system; directions can be communicated unambiguously, provided that everybody uses the same coordinate system.

It is precisely for this reason that the right hand rule can (and should) be used for rotational motion. Consider the hands of an analog clock. Assuming that the clock is a typical one, it will have hands that turn “clockwise” when viewed from the “usual” point of view, but if the clock had a transparent back and you were to view it from the back you would see the hands turning “counterclockwise!” The observed direction of rotation (clockwise or counterclockwise) depends on the observer’s point of view.

Instead of using clockwise and counterclockwise, we can describe the direction of rotation with a right hand rule: if you curl the fingers of your right hand around with the direction of the rotational motion, your thumb will point in the direction of rotation, which will be along the axis of rotation. Applying this to the above we find that when viewing a clock from the front, the rotation of the hands is three dimensionally into the clock (away from the observer), and when viewing a clock from the back side, the rotation of the hands is three dimensionally out of the clock (toward the observer). If two people view a transparent clock at the same time but one observes it from the front while the other observes it from the back (i.e. the clock is between the two people who are facing each other), they will disagree on which way the hands turn (clockwise or counterclockwise) but will agree on this direction if both use the right hand rule convention to describe the direction of the rotational motion – both observers will agree that it is directed toward the person viewing the back side of the clock.

When first learning about the right hand rule, students are often initially confused, with many students failing to grasp why such a rule is even useful in the first place. Before introducing the right hand rule I like to begin by holding an object such as a meter stick while standing at the front of the classroom. I then rotate the meter stick through its center so that the students claim that it is rotating “clockwise” when asked. Being careful to keep the rotational motion as constant as possible, I then walk to the back of the room. It’s important that the students see that at no point did I stop the rotation of the meter stick – it is still turning the same way as before, and yet at some point each student finds that they must turn around in order to continue to see it. Many students are astonished to see that the meter stick is now rotating counter clockwise from their (now reversed) point of view. This helps establish the need for a better way to describe rotation.

I then introduce the right hand rule and go through a couple of examples. Traditionally, this would have been the end of it, but last year I was able to take advantage of my newly acquired PASCO Smart Cart, which has a wireless 3-axis gyroscope (i.e. rotational sensor). The coordinate system is fixed with respect to the cart, and is printed on the cart itself, but I like to make this more visible by attaching cardboard cutout vectors onto the cart which make the axes more visible to the students while I hold the cart up for them to see. I then set up a projected display of the angular velocity of the cart along each axis simultaneously. I then ask the students how I must turn the cart in order to get a desired rotation of my choosing (i.e. ±x, ±y, and ±z).

I really like how the carts, along with the live display of the 3 angular velocity components make the admittedly abstract right hand rule so much more concrete. Seeing the display agree with our predictions makes it so much more real and is much, much better than me merely saying “trust me.” I have found that introducing and using this right hand rule with rotation has made using this same rule much more natural when using it to later relate the direction of current flow and the magnetic field.

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