Simple Circuits, LEDs, and Paper Circuit Design Challenges

By: Meghan Thoreau, OSU Extension Educator, Community Development & STEM, Pickaway County

Simple Circuits with Meghan Thoreau, OSU Extension Educator, and Judy Walley, Teays Valley Chemistry Teacher. Full presentation link: go.osu.edu/simplecircuits

Why Understanding Simple Circuits is Important?

Basic circuit knowledge is important for many different disciplines, engineering, physics, chemistry, and mathematics. It’s also useful knowledge around this time of year when you may need to repair a string of old holiday lights? Understanding and building simple circuits show us important concepts learned in school that can describe useful real-world systems, like devices we use every day, cell phones, light switches, Chromebooks, cars, etc.

The electric charge that flows through your house is called your electric circuits. This carries useful energy through your house that you can transform into other forms of energy to do various tasks. The US standard household circuit has an effective voltage that takes 120-volts. Volts represent the energy per unit charge. We discussed these basic building blocks of simple circuits in STEM Club this month. Our hands-on simple circuit design challenge uses 3-volt lithium batteries. Before jumping into our design challenges we’ll cover a few basic circuitry concepts and energy principles.

For program presentation, click here.

Conservation of Energy, First Law of Thermodynamics

The conservation of energy principle was discovered and published by Julius Robert von Mayer in 1842. Mayer was a German physicianchemist, and physicist and one of the founders of thermodynamics. However, there were many others working in the field that made significant contributions, such as, James Prescott Joule, Hermann von HelmholtzAlessandro Volta, and Benjamin Thomson.

The principle of conservation of energy is an effective tool in solving problems and understanding how different forms of energy directly impact our lives. There are also benefits to this principle. These include recycling of materials, lower energy costs for consumers, less pollution due to a reduction in the use of fossil fuels, and less harm to animals and the environment. We watched a short video, from Two Minute Classroom, that explained the basic concepts of how energy transforms itself into other forms and never truly disappears or is destroyed.

Below are 10 common types of energy:

Image source: https://www.thoughtco.com/main-energy-forms-and-examples-609254

Atoms and Electrons

Judy Walley led students through the basic concepts of atoms and electrons, because, without the flow of electrons, we have no electric circuit to work with.

Screenshot of our recorded club meeting where Judy Walley explains the basic concepts of atoms and electrons.

Walley also explained the chemistry of a battery and how chemical reactions occur inside the battery that causes an imbalance or a build-up of electrons (-) on one side of the battery over the other, hence why one side or one terminal of the battery is negative (-) and the other positive (+). We also introduced the basic materials for our hands-on design challenges and explain how a battery works.

Screenshot from our virtual simple circuit presentation.

How a Battery Works

Batteries are important to everyday life. Batteries are essential to most electrical devices. They exist in our cars, cell phones, laptops, and other electronic appliances, and serve as critical backup sources of electricity in telecommunications, public transportation, and medical devices. A battery is essentially a container full of chemicals that produce electrons (-). Inside the battery itself, a chemical reaction produces the electrons.

The battery is a device that stores chemical energy and converts it to electrical energy. The chemical reactions in a battery involve the flow of electrons from one material (electrode) to another, through an external circuit. The flow of electrons provides an electric current that can be used to do work. In our case, students use copper tape to build a paper circuit to create light energy with an LED. Below depicts the inner wors of a battery.

Screenshot of how a battery works from our virtual simple circuit presentation.

The students learned that a battery has three main parts: an anode (-), a cathode (+), and the electrolyte that separates the two terminal ends on the battery. We discussed the chemical reaction happening inside the battery that causes electrons (-) to buildup on one side of the battery causing one end to be negatively charged (-) and the other end positively charged (+). This buildup causes an imbalance of electrons (-), that want to travel to the other side of the battery, but can’t move freely until a conductive circuit is completely looped for the electrons to travel through; in our case, the conduit is copper tape.

When a circuit is complete, or a loop created, the electrons will flow through the conductive paths racing to reach the other side of the battery terminal. When the electrons flow through the loop, the chemical energy inside the battery is transformed into electrical energy running through the circuit. When all electrons (-) make it to the other side, the battery stops working. All of the electric energy was transformed into other forms of energy.

Electrical energy allows us to do work by transforming energy into other forms. We use LEDs in our paper circuit design challenge because it’s a simple way to show how electric energy is transformed or converted into light energy. We could replace the LED with a simple motor and the motor would convert electrical energy into kinetic.

Screenshot of simple circuit components and electricity concepts from our virtual simple circuit presentation.

What’s a Diode?

Both LEDs and motors can easily be added to simple circuits. However, LEDs are somewhat more restrictive than motors, because LEDs are diodes. A diode only allows current to flow in one direction. From the cathode (-) leg of the LED through the anode (+) leg. Note that the anode on a battery is negatively charged, but the anode on an LED is positively charged! The correct way to connect an LED legs to the battery terminals is positive to positive/anode to cathode and negative to negative/ cathode to anode. Study the image above if this is confusing. If the LED or battery are flipped in the wrong configuration then no current or electrons flow through the LED because the diode only allows for current to flow in one direction.

Image source: https://diotlabs.daraghbyrne.me/docs/controlling-outputs-motors/diodes/

A motor does not have a diode, therefore current can flow in either direction, and depending on how the motor is connected to the battery will decide what direction the motor turns left/right, or moves forwards/backward.

Image source: https://www.robotroom.com/DPDT-Bidirectional-Motor-Switch.html

Electric Circuit Design Challenges

As a virtual group, we challenged ourselves with a few NearPod activities to reinforce our electricity concepts before beginning our hands-on paper circuit challenges. A paper circuit is a functioning electronic circuit built on a paper surface instead of a printed circuit board (PCB). Projects can range from greeting cards to origami, to traditional art such as paintings or drawings. STEM totes went home with the students and included paper circuit design challenges and supplies.

Supply List

  • LED
  • Conductive copper tape
  • Plain card stock, or templates printed on card stock
  • 3-V coin cell battery
  • Tape (not included)
  • Binder Clip

Other useful items: multicolor/print card stock, glue stick, scissors, pencils, markers

We went through two paper circuit-build challenges with an independent bonus design challenge. The first design is depicted below. It had a basic road map for us to follow, which we added labels to ensure our understanding of which direction the electrons were flowing and which direction the current was flowing as well as how to position and connect the battery and LED to the circuit correctly.

The second

Once you start learning the basics of paper circuit design you can explore more crafty designs to create circuit cards for all occasions and topics. A few ideas shared at our club meeting:

Entomology STEM Club Challenges

By: Meghan Thoreau, OSU Extension Educator, Community Development & STEM, Pickaway County

Entomology is the study of insects. More than one million different species of insect have been identified to date. Insects are the most abundant group of animals in the world and live in almost every habitat. Entomology is essential to our understanding of human disease, agriculture, evolution, ecology, and biodiversity.

Entomology is an ancient science, dating back to the establishment of biology as a formal field of study by Aristotle (384-322 BC). There are even earlier references to the use of insects in daily life: such as the growing of silkworms that began 4700 BC in China, which was an important part of peasant life in China, as early as 4000 BC. More than a hundred years ago, entomologists formed a society, the Entomological Society of America (ESA), to promote the science and study of entomology in the United States. (i)

Photo source: https://www.todayifoundout.com/wp-content/uploads/2014/10/silk-worm.jpg

On our second day, Future Entomologist, we explored our previous bug topics a bit deeper and also focused on the diverse career pathways open to Entomologists. We also focused on the chemistry behind some insects (such as color change, odor, etc.,) and some interactive bug challenges to strengthen our understanding of insect characteristics and insect identification.

Meeting agenda for Future Entomology with Meghan Thoreau, OSU Extension Educator. Full presentation link: go.osu.edu/entomology

Who Needs Entomologists?

Entomologists have many important jobs, such as the study of the classification, life cycle, distribution, physiology, behavior, ecology, and population dynamics of insects, but their scoop of study is pretty diverse, ranging from agricultural pests, urban pests, forest pests, medical pests, and veterinary pests and bug control. Entomologists are scientists, researchers, teachers, and consultants and can work for private companies, universities, or government agencies.

There are more than 8,000 men and women who work as professional entomologists in the United States (more worldwide) and are sought over for their specializations and expertise. They have careers in teaching; working as Extension Entomologists (public educators who provide information on insects and their management in agricultural and urban environments); raising bees; enforcing quarantines and regulations; performing insect survey work; consulting on integrated pest management topics; consulting in the construction sector or cosmic industry, selling insecticides; controlling pests; and conducting research on insect classification, taxonomy, biology, ecology, behavior, and control – and these jobs are found both local, national, and around the world; e.g. employed by the United Nations. Like to travel? Here are is a random job pull from the United Nations job board.

Photo source: https://unjobs.org/themes/entomology

The greatest number of entomologists are employed in some aspect of economic or applied entomology that deals with the control of harmful insects. There are also tens of thousands of amateur entomologists and hobbyists who study insects without pay and who provide valuable information on insect distributions, seasonal activity patterns, identification, life cycles, and behavior. (ii)

Slide from Future Entomology unit created by Meghan Thoreau in Keynote.

Career possibilities for graduates with a B.S. degree in Entomology include:

  • Agricultural, biological or genetic research
  • Forensic entomology
  • Public health
  • Consulting (agricultural, environmental, public health, urban, food processing)
  • State and federal government agencies
  • Conservation and environmental biology
  • Pharmaceutical industry
  • Natural resources management
  • Veterinary, medical, or graduate school
  • Production agriculture
  • Pest control
  • Seed, fertilizer, and chemical research companies
  • Apiculture
  • Outreach education

Sometimes the best career opening decisions come from learning how others may have indirectly or directly stumbled into their chosen career pathway. Careers are not always linked to taking the right courses in college, but understanding personal strengthens and skillsets, as well as, letting the randomness of life decision making along with the people/network you may know all start laying the foundations for our various career paths. Read more, How Three Entomologists Found Careers in Industry.

Interactive Activity Challenge for Readers

Watch this short clip, Arthropods: the Differences Between Spiders and Insects and then click and run through the ‘Parts of an Insect and Spider’ challenges and try to get your name placed on our STEMist scoreboard! You can also play our Kahoots Insect Trivia, game link below as well.

Below are two interactive Entomology WordWall Challenges from our November 21, 2020, STEM Club meeting!

1. Parts of an Insect

2. Parts of a Spider

3. Kahoots Bug Trivia
Join at www.kahoot.it and enter the Game Pin shared live during our club meeting!
References
(i) http://entomology.wsu.edu/prospective-students/the-what-why-of-entomology/
(ii) https://www.aboutbioscience.org/careers/entomologist/

STEM Professionals Panel: learn, engage, and explore four STEM career pathways

Get ready STEM Club, because we have four guest professionals coming to join us for some lively discussion on their STEM careers, life experiences, and tips when considering working towards a STEM Career. Save the date: Thursday, 21 May 2020 @ 4:00 P.M. (Zoom meeting details are found in our Elementary STEM Club’s Google Classroom.) Click here to watch the recorded club meeting. Our panel includes the following:

WILLIAM MILLER-LITTLE is a M.D. Ph.D. Medical Candidate & Researcher at Case Western Reserve University School of Medicine, Department of Pathology/Immunology actively works in a research laboratory.

MELISSA SMITH is a Phlebotomist & Clinical Lab Supervisor Technician at OSU Medical Center, Outpatient Care East Lab in Columbus, OH (and STEM Club mom.) 

KARINA HANKENFOF is a Product Engineer & Lab Technician, specialized in materials and mechanical systems with Cincinnati Testing Labs in Cincinnati, OH (and Teays Valley alumni.)

CLAY BURGETT is a Chemist & Information Technology Manager at the American Chemical Society for the Chemical Abstracts Service (CAS), a division of the American Chemical Society in Columbus, Ohio.

COSI Science Festival’s Meet A Scientist Library Youth Program

STEM Club students, please take advantage of this free virtual library youth program made possible through a community collaboration between COSI, DuPont (Circleville), Pickaway County Library, and OSU Extension. Pre-register now!

COSI Science Festival’s Meet A Scientist Youth Program, Saturday, May 9, 2020, 11:00 AM – Peggy Scott, a Dupont polymer scientist, and Christy Yu, a Dupont quality engineer, share their personal experiences and passion for STEM careers to youth and their families. Learn about polymer chemistry, science careers, and engage in a virtual polymer-scavenger hunt from the comfort of your home. Pre-registration is required for this free educational event, go to, go.osu.edu/polymeryouthprogram. After registering, you will receive a confirmation email containing information and passcode to join the meeting. We’ll also send a reminder email prior to the event. #COSISciFest

For more information please email, thoreau.1@osu.edu. Here is the recording of the Polymer Scientist program! 

Video Conferencing Etiquette, Summary Writing Challenge, and Big Bang AR App!

By: Meghan Thoreau, OSU Extension Educator

Virtual STEM Club: video conferencing in a nutshell Prezi, go.osu.edu/videomeetings.

A significant part of the world population is currently on lock-down in an attempt to contain the coronavirus pandemic. People are turning to technology to go to school, to work, to communicate and stay in touch with their classmates, colleagues, friends, and family.

We held our first virtual STEM Club session last Friday through Zoom! It was great to see everyone’s faces, check-in, and teach video conferencing skills and virtual meeting etiquette; click here to review our presentation again with your child.

Young STEMist learning video conferencing skills.

VIDEO CONFERENCING ETIQUETTE (skill building)

Students learned some quick Dos and Don’ts in participating in virtual meetings:

  • Ensure your technology is working
  • Be on time
  • Mute yourself when not speaking
  • Wear school-appropriate clothing
  • Sit eye-level to camera’s lens, framing yourself from the midsection up
  • Ensuring the right lighting
  • Looking into the camera, giving audience eye-contact
  • Pay attention
  • Have a clean, simple, organized background, or upload a virtual backdrop

SUMMARY WRITING CHALLENGE

Summary writing isn’t simple. It’s a difficult academic skill. As with any new skill, especially writing skills, students need to be explicitly taught and practice. The students went through some basic definitions and discussed why summary writing is important because it improves reading skills as you pick out the main ideas of reading; it also helps with vocabulary skills where you paraphrase a reading, altering the vocabulary and grammar as you do so.

A summary is a long text distilled to its essentials. It summarizes the key points worth noting, without writing examples and lengthy details. The sentence structure and vocabulary has been changed, but the main ideas remain. Critical thinking skills are improved as you decide on the main ideas of the reading to include in the summary. Summary writing also improves editing skills as you draft and edit the summary. It’s helpful to work with peers throughout the writing and revision process – cooperative learning.

Screenshot of Time for Kids reading resource: https://www.timeforkids.com/.

The students were asked to visit, Time for Kids, and read two short expository readings, select one article to write a summary on. (Time for Kids has currently opened it’s a digital library for free!) It’s important to underline or take notes of the main ideas as students read. More details to the assignment and submitting are found in your student’s Google Classroom, logging in with their student Teays Valley email address. If you experience any issues with Google Classroom, contact, Meghan, thoreau.1@osu.edu.

BIG BANG AR APP

The students learned about astronomy, elements, atoms, and virtual reality technology in previous club programs. We thought this free App engages many of the lessons learned in a fun interactive way to learn about the story of our universe. The Big Bang AR App is available on both the Google Play and Apple stores.

This is an immersive learning App designed by Tilda Swinton and CERN scientists to take people on an “epic interactive journey through the birth and evolution of the universe” – in mixed reality and augmented reality. It takes students “back 13.8 billion years and discovers how space, time, and the visible universe came to be.” Students can see the universe form in the palm of their hand and virtually “witness the formation of the very first stars, our solar system, and the planet we call home.” This lesson allows students to learn about the microscopic building blocks that make up everything – and everyone – we know, and find out if we are made of stars. The experience ends with the student able to take a #starselfie and share it with your friends and post it in Google Classroom!

Here are a few of the student #starselfie shares:

STEM Stars!

Please stay tuned while we continue to plan and line up guest speakers for our future Virtual STEM Club programs.

Quotes above from the Apple store description: https://apps.apple.com/us/app/big-bang-ar/id1453396628.

 

Chem Basics and Career Exploration

By: Meghan Thoreau, OSU Extension Educator

Last month our young STEMists tacked chemistry basics, the periodic table, what makes up an atom, and chemical and physical changes. (Note: 360-video @ the end of the post!)

DAY 1

The students started the club session with an interactive presentation highlighting several careers in chemistry. All the careers mentioned have a short career highlight video to provide good visualizes of what the jobs entail, as well as how much additional education is expected. The students also learned the differences between credentials, such as an Associate Degree, a Bachler’s, a Master’s, and having a PhD. We were only able to allow the kids to pick five or six careers during the club, so please sit down and re-explore the interactive presentation with your child at home!

Figure 1: Image from the program presentation by Meghan Thoreau, go.osu.edu/chemistrycareers.

They learned about atoms, which is made up of three tiny kinds of particles called subatomic particles: protons, neutrons, and electrons. The protons and the neutrons make up the center of the atom called the nucleus and the electrons fly around above the nucleus in a small cloud.

Figure 2: Photo by Meghan Thoreau captures one of Ms. Walley’s many chemistry wearables. The sweater shirt depicts the element Helium. Helium’s atomic parts are pictures to the right.

Figure 3: the periodic table.

The students then began exploring the periodic table and how elements are organized and what different forms the elements exist at room temperature. They further familiarized themselves by playing a couple of games: Element Scrabble, spelling words with the element’s symbols and Periodic Table Battleship, strategically call out the period, the group, and the name of each element to sink their opponent’s ships.

Figure 4: Photos by Meghan Thoreau depicting element scrabble and periodic battleship learning games.

DAY 2

Students applied what they learned from Day 1 about chemical and physical changes to the hands-on chem labs. They learned that chemical changes have certain indicators: change in color, gas produced, temperature change, light produced, precipitate forms, or are irreversible.

The students broke up into groups and did a series of chemical experiments to see first hand what chemical changes look, feel, and smell like.

Figure 5: video highlight of STEM Club: Chem Basics by Meghan Thoreau produced in iMovies. Retrieve from: https://youtu.be/peZvyjRWB9s.

If slime is still permitted in your household and you’re looking for a Super Fluffy Slime Recipe try this:

  1. put 3 cups shaving cream in a bowl
  2. Add in 1/4-1/2 tsp of baking soda and stir
  3. Mix in 1/2 cup of glue and stir
  4. Add 1 full tbsp of saline solution and a coating on hands
  5. Mix until mixture forms a fluffy slimeball

Next month Dr. Brooke Beam, OSU Extension Educator from Highland County will lead us into learning about 360 technology and video and photo production. The students will be exposed to 360 educational VR experiences for an immersive learning adventure. Testing out the new 360 camera, here’s a clip below:

Figure 6: 360 short video highlight of STEM Club: Chem Basics by Meghan Thoreau produced in GoPro. Retrieve from: https://youtu.be/6JUQny_TdPI.


 

Club Highlights from 2018-2019

By: Meghan Thoreau, OSU Extension

LED Display Circuit Board Challenge

Elementary STEM Club just started its third year of STEM (science, technology, engineering, math) programming, engaging approximately a hundred 4th and 5th graders in after school hands-on STEM challenges and career exploration throughout the academic school year. Judy Walley, Teays Valley High School Chemistry Teacher, and Meghan Thoreau, OSU Extension Educator, co-teach the program, which also involves over two dozen high school mentor students. The mentors assist with club activities while themselves gaining both soft and technical skills, leadership, community service, and college/career exploration opportunities.

Physics and Center of Gravity Challenges

STEM education programs can have a positive impact on students’ attitudes towards STEM disciplines, 21st century skills, and a greater interest in STEM careers. Educators throughout Pickaway County have been busy in supporting a number of problem-based learning initiatives, business-teacher partnerships, and STEM teaching initiatives.

Foldscope, Origami Microscope Biology Challenge

Elementary STEM Club is one of those local initiatives that employs hands-on learning through a multidisciplinary approach into many subjects and career paths. The program challenges its youth in chemistry, astronomy, biology, coding, drone technology, connected toys, wearable tech, strategic mind games, escape classrooms, electric circuits, physics, renewable energy, beekeeping, aerospace, flight simulations, aviation, fostering a community service mindset, and more.

Strategic Mind Games and Bee Science Challenges

We invite specialists from the community to teach, share, and engage with the students, such as the Scioto Valley Beekeeping Association, OSU Professors, an Extension Energy Specialist, an OSU Health Dietitian, and the Civil Air Patrol to name a few. Next year we’re hoping to bring some virtual reality, 360 photography, and video production challenges to our students. If you’re interested in sharing a skillset, a technology, a career path, or a meaningful life experience to some amazing and eager-minded students, please email, thoreau.1@osu.edu or jwalley@tvsd.us.

We’d like to also thank everyone who has been involved in the program over the last two years. It’s been a pleasure and a plunge into the wild side of STEM education, youth workforce development, and promoting a mindset of lifelong learning – all critical to today’s workforce.

Civil Air Patrol and Aerospace Careers

Civil Air Patrol

We ended last year with a great program partnering with Civil Air Patrol (CAP). Civilian volunteers – with a passion for flight, science, and engineering – led the program highlighting STEM careers in aviation, space, cyber security, emergency services, and the military. The whole organization is powered by a team of dedicated civilian volunteers with a passion for aviation and STEM education. If you know of a student, 12-years and up, that has in interest in aviation, would like a chance to fly a plane, work towards their pilot license, attend leadership encampments, career academies, and more, visit http://www.ohwg.cap.gov/.

Aerospace Officer Donna Herald, Lieutenant Casey Green, and Lieutenant Colonel David Dlugiewicz volunteered their time and aviation skills to lead our youth into exploring the history of the Civil Air Patrol, emphasize the value of civic engagement, and underscore the growing deficient of pilots and aerospace specialist in the workforce.

Physics Concepts, Bernoulli Principle on Air Pressure Differential Theory Challenges

The CAP lessons built on previous STEM Club programming that taught physic concepts, the law of gravity, and re-instilled aircraft principal axes, such as the friction, center of gravity, and coding parrot drones challenges. Lieutenant Colonel Dlugiewicz taught the discussed Bernoulli Principle (an air pressure differential theory) and Sir Isaac Newton and the laws of motion and lift. The students engaged in a hands-on activity such as filling an air bag with one breath, leaving a gap between their mouth and the bag to allow a vacuum to form, demonstrating Bernoulli’s principle.

Part of a Airplane and Axis Challenges

Lieutenant Casey Green discussed the parts of an airplane focusing on the components that control an aircraft’s moment and direction. The students broke into groups and rotated between two stations. The first engaged the students in building paper airplane that they cut strategic slits into. The students experimented by folding different components of their airplanes to change and control the overall direction of their paper airplanes. The second station engaged the students in two different sets of CAP flight simulators to further the students’ understandings of the aviation principles taught in the program. The flight simulators provided a semi authentic experience that helps young pilots learn to fly.

Flight Simulator Challenges

Our community has some amazing young minds that are thinking and embrace the many dynamic career pathways of a STEMist. Please get involved and support more STEM programming in your community, it matters.

 

Halloween STEM Challenges: chemistry of color, vision, and slime

By: Meghan Thoreau, OSU Extension Educator

October’s STEM Club

We thought we’d take advantage of the spooky mystery themes of Halloween and challenge our students to become science detectives, experimenting with hands-on activities involving chromatography, perception of vision, and phosphorescent slime chemistry.

Chromatography

The students became CSI lab technicians, tasked with solving a who-done-it pumpkin theft. All that was left at the scene of the crime was a letter demanding cookies! No finger prints were found, but six suspects where brought in for questioning and all six had different black markers on their person. The marker evidence was tagged and brought to the CSI lab along with the random letter for further analysis. Marker samples were taken and a chromatography test was performed by our young lab technicians.

Chromatography is a laboratory technique for the separation of a mixture (more specifically separation of molecules) and in our case black marker ink molecules. The ink was dissolved in a water solution process of a mobile to stationary phase, revealing distinct ink-finger prints for comparative analysis against an ink sample taken from the random note. The students discovered different ink molecules travel at different speeds, causing them to separate and reveal distinct color patterns that could help identify the pumpkin thief from the six suspects.

People don’t often pick up a marker or pen and think of molecules,  but ink and paints are made up of atoms and the molecules, like everything, follow rules. Ink and paints follows the standard CPK rule, which is a popular color convention for distinguishing atoms of different chemical elements in molecular modeling (named after the chemists Robert Corey, Linus Pauling, and Walter Koltun). Basically, certain elements are associated with different color. For example,

  • Hydrogen = White
  • Oxygen = Red
  • Chlorine = Green
  • Nitrogen = Blue
  • Carbon = Grey
  • Sulphur = Yellow
  • Phosphorus = Orange
  • Other = Varies – mostly Dark Red/Pink/Maroon

PERCEPTION OF VISION

Persistence of vision refers to the optical illusion that occurs when visual perception of an object does not cease for some time after the rays of light proceeding from it have ceased to enter the eye. The discovery was first discussed in 1824 when an English-Swiss physicist named Peter Mark Roget presented a paper, “Explanation of an Optical Deception in the Appearance of the Spokes of a Wheel when seen through Vertical Apertures” to the Royal Society in London. Shortly after, in 1832, a Belgian physicist Joseph Plateau built a toy that took advantage of the optical illusion trick. (Photo below source: http://streamline.filmstruck.com/2012/01/07/the-persistence-of-persistence-of-vision/)

The toy made images move independently, but over lapped them or when placed in a series made them look as if they were walking, running, juggling, dancing. This concept soon laid the foundation to early film making. (Photo below source be: http://1125996089.rsc.cdn77.org/wp-content/uploads/2011/12/persistence-of-vision-transit.jpg)

The students learned how our eyes report basic imaginary back to the brain, or rather how our eyes perceive shapes, their motion, and their relative position from other objects. The students discovered that eyes are not simple windows to the world. Eyes do not see what is, but instead see approximations.

PHOSPHORESCENT SLIME

The students learned how different objects glow in the dark. First, students learned that heat is a good emitter of light, such as a fire or an old-fashioned light bulb, but heat isn’t always required to make something appear to glow. For example, bedroom glow-in-the-dark stickers, glow sticks, or fireflies do not require heat. The stickers and even certain types of rocks, like the Bologna Stone, require several hours of light to charge them in order to later glow. But glow sticks and fireflies, do not require heat or light, but instead deal with chemistry where two different elements are mixed together to make a ‘luminescent’ compound.

We talked about phosphorescence and the process in which energy absorbed by a substance is released slowly in the form of light. Unlike the relatively swift reactions in fluorescence, such as those seen in a common fluorescent tube, phosphorescent materials “store” absorbed energy for a longer time, as the processes required to re-emit energy occur less often.

Finally, we let the students become chemists and make their own phosphorescent slime for later glow in the dark fun after the compound was charged by light. The young chemists used measuring devices to concoct their spooky slime recipe.

Make another batch at home with your young chemist:

  1. Add 20.0 mL of glue to cup
  2. Add 15.0 mL of water to cup
  3. STIR!
  4. Drop of preferred food coloring
  5. STIR!
  6. Add a drop of glow in the dark phosphorescence paint
  7. Add 12.0 mL of BORAX solution
  8. STIR! It will be runny until you take it out of the cup and start to play with it.

Next month we will be challenging our STEMist in Mind and Body Challenges! Stay tuned to learn more about November’s STEM adventures.