## Exploratory Stations: simple circuits, magnets, and Makey Makeys builds

By: Meghan Thoreau, OSU Extension Educator

The short program highlights videos of the simple circuits, electrical stations, and Makey Makey exploration stations.

This month students built on their electricity skills introduced in September to better understand how electricity and magnetism are related, as well as learned about other forces that can accelerate a body, or how the center of gravity is a pulling force that acts upon two things.

A student proudly shows off their center of gravity project.

#### Center of Gravity

We explored balancing basics and the center of gravity. Students learned that if they support the center of gravity, the object will balance and be stable. If an object is not supported directly below its centre of gravity then the object will be unstable and topple over. Any object is more stable when the center of gravity is near the center of the base of support. Wobbler toys are another example of using physics, torque, and the center of gravity to keep toddlers entertained for hours. (1)

Students had an opportunity to look at several types of balancing objects and understand how each object’s mass was distributed and how stable its center of gravity was. For example, they were able to interact with objects with different bases and structural shapes and see firsthand that a smaller base is less stable than an object with a larger base. A triangular pyramid shape is much more stable sitting on its broad base than on its point, which in turn can also serve as a resting point to balance another object because of its stability and take advantage of the upper object’s center of gravity.

A balancing toy utilizes the concepts of stability and low center of gravity. By having two heavyweights on the two sides, the toy will make the object very stable. The students learned about stable systems and how they return to their state of initial rest after disruption or being disturbed. (2)

After class-led activities, students broke into groups and rotated through simple circuits, magnets, electromagnets, Makey Makey interactive installations, and origami-making stations.

#### Simple Closed Loop Circuit

Electrical devices surround us every day – calculators, space heaters, remote controls, lights, cell phones, drones, electric vehicles. Students started with the voltage source such as a battery that is required to close the circuit and operate the device. As the students moved to the different stations they engaged in the science and engineering practice of making observations as they used batteries, wires, small light bulbs, and light bulb holders to explore the phenomenon of electricity and learn the difference between open and closed circuits. They also engaged in concepts of electric current, energy transfer, and electromagnets, and how circuits can be used with circuit boards and code to make more advanced electrical systems and work.

Examples of some of the simple closed-loop circuit stations and electromagnetic exploration stations.

#### Makey Makey Circuit Board Stations (using coding)

Makey Makey is a circuit board that you plug into your computer and in some ways acts like a keyboard. Each metal pad that you see on the Makey Makey is a conductive touchpad. The touchpad can be connected to other things in a circuit to invent and try out different design concepts. Alligator clips and a USB cable can be connected to the circuit board to complete closed-loop electrical signals to send the computer either by a keyboard stroke, or sensory touch that closes the loop. In the Makey Makey stations, depicted below, students interacted and explored a coded electrical guitar, an electrical keyboard, and an interactive educational poster on butterflies. Makey Makeys are powerful tools for youth to use for prototype electrical ideas for more advanced designs and projects.

Pictures Makey Makey coded projects that used Scratch and a Makey Makey circuit poster-coded program that the educator prerecorded sound bits and GIF images into for the circuit to play when closed.

#### Engineering Connection

Electrical engineers design the circuits and batteries that are in the devices and appliances that we use every day. Circuits can be found in music players, computers, video games, appliances, microwaves, phones, televisions, cameras, medical equipment, vehicles, and many more products. Engineers take seriously the responsibility of designing circuits that work dependably and safely. While new devices are constantly being developed around the world, engineers strive to create safer, more efficient products that ultimately help improve people’s lives.

1 Balance basics. Science World. (2022, June 9). https://www.scienceworld.ca/resource/balance-baseics/#:~:text=If%20you%20support%20the%20centre,of%20the%20base%20of%20support.

2 Evantoh. (2023, October 20). Evan’s space. Evan’s Space. https://evantoh23.wordpress.com/

## Engineering a Speaker: vibration, sound waves, electricity, and electromagnetism build challenge

By: Meghan Thoreau, OSU Extension Educator

Dr. Betty Lise Anderson, Professor of Electrical and Computer Engineering at The Ohio State University is pictured engaging Ashville Elementary students on principles of sound, magnetism, electricity, and constructing a speaker.

This year’s STEM Club started by welcoming guest educators Dr. Betty Lise Anderson and Lecturer, Clayton Greenbaum, both from OSU’s Department of Electrical and Computer Engineering. Each led students to explore more concepts on vibration, sound waves, electromagnetism, magnet fields, current (I), and how to build an electromagnet to use in constructing a working speaker project to take home. It’s our hope that the students plug in their speakers and share what they learned in our club meeting with their families.

Dr. Anderson runs a popular ECE outreach program that helps K-12 students, and their teachers explore electrical and computer engineering concepts with a variety of hands-on electrical projects. This program is specifically designed to encourage students toward STEM fields and to specifically increase the number of women and minorities in engineering. In 2015, the program won Ohio State’s top university-wide Outreach Award.

Ashville elementary students building to construct their speaker.

Along with the team of Educators, several OSU college students’ volunteers, and Teays Valley High School volunteers came to mentor the elementary students and provide additional opportunities for students to engage and ask questions.

OSU college students teaching magnetism concepts with Walnut elementary students.

#### How does your ear process sound waves?

Sound waves enter the outer ear and travel through a narrow passageway called the ear canal, which leads to the eardrum. The eardrum vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear. These bones are called the malleus, incus, and stapes.

The bones in the middle ear amplify the sound vibrations and send them to the cochlea, which is filled with fluid. Once the vibrations cause the fluid inside the cochlea to ripple, a traveling wave forms along the basilar membrane. Hair cells, sensory cells, sitting on top of the basilar membrane—ride the wave. Hair cells near the wide end of the cochlea detect higher-pitched sounds, such as an infant crying. Those closer to the center detect lower-pitched sounds, such as a large dog barking.

As the hair cells move up and down, microscopic hair-like projections (known as stereocilia) perch on top of the hair cells bump against an overlying structure and bend. Bending causes pore-like channels, which are at the tips of the stereocilia, to open up. When that happens, chemicals rush into the cells, creating an electrical signal.

The auditory nerve carries this electrical signal to the brain, which turns it into a sound that we recognize and understand. (1)

#### What is an electromagnet?

An electromagnet is a coil of wire wrapped around a ferromagnetic material that becomes magnetized when electric current flows through it. Electromagnets are used in common electric devices. Here is a close-up of an electromagnet the students coiled up and attached to the base of their paper diaphragm.

Slow-motion video of speaker (note this one is driven by a source a little more substantial than a cell phone!) Credit: Clayton Greenbaum.

#### Why does a speaker need an electromagnet?

Every speaker has an electrical current. When the current is changing, it produces a magnetic field. To make the cone (or panel) of the speaker move, magnets are used to create an opposing magnetic field which creates vibrations. These vibrations are the sound we hear.

Lecturer, Clayton Greenbaum leads a club meeting highlighting the speed at which technology advances exponentially and the importance of students understanding the immediate need for problem-solving minds to enter the workforce and solve problems created by human technologies.

1 U.S. Department of Health and Human Services. (n.d.). How do we hear? National Institute of Deafness and Other Communication Disorders. https://www.nidcd.nih.gov/health/how-do-we-hear#:~:text=Sound%20waves%20enter%20the%20outer,malleus%2C%20incus%2C%20and%20stapes.