Supporting Image
May 19, 2023 0    
Electric Crystals, Part 4
Electric Crystals and their Broken Symmetries

Students learn how some crystals produce electricity when squeezed (by the piezoelectric effect). Students perform calculations and explore engineering applications of piezo-devices to deepen understanding and engagement. This lesson is part 4 of a 4 part series. 


Approx time: 45 minutes
Things you'll need:
Step 1

Crystals' Shocking Properties

One of crystals' seemingly magical properties: the piezoelectric effect!

The comic introduces the concept of piezoelectricity: the phenomenon where a mechanical deformation results in a small charge on the surface of a crystal.

Vocab
piezoelectric: mechanical deformations result in a small electric charge

Fig. 1 (Click to enlarge).
Fig. 1 (Click to enlarge).
Step 2

Dipole Moment

Learn about dipole moment of a configuration of charges.

Read the worksheet's explanation of dipole moment, and how geometry affects electric charge just as much as charge magnitude does. Students are guided through an example dipole moment calculation for an undeformed NaCl configuration. They're then prompted to calculate the dipole moment for the SiO2 configurations.

Vocab
dipole moment: quantifies the strength a charge separation, can be detected as an electrical signal

Fig. 2 (Click to enlarge).
Fig. 2 (Click to enlarge).
Step 3

Symmetry is Key

Check in with a video about the effects of symmetry on crystal properties.

In this video Madelyn explains the source of piezoelectricity and how the symmetry of atoms inside a unit cell determines whether the material is piezoelectric. Students will then reflect on their NaCl and SiO2 calculations with this new explanation in mind.

Step 4

Identify the Device

Based on schematic diagrams, determine the identity of devices with piezos.

The properties of piezoelectric crystals mean they can be used as a a sensor or an actuator. Listed in a wordbank are six devices which use actual piezos. Students will use the wordbank to determine which devices are represented by the schematic diagrams.

Fig. 4 (Click to enlarge).
Fig. 4 (Click to enlarge).
Step 5

The Crystal Factory Feedback Form

Please fill out the survey to leave feedback for The Crystal Factory employees.

On this feedback form students can reflect on their favorite part of the tour, any remaining questions, and topics they're excited to learn more about. The comic ends with Krista geeking out about the amazing applications of symmetry and crystals, and the students on the tour seem to really get the message!

Fig. 5 (Click to enlarge).
Fig. 5 (Click to enlarge).
Why it Works

Supplemental materials for teachers can be found at the Galactic Polymath website, where you will find information on learning standards and be able to provide feedback on the lesson.

Don't stop here! This is part 4 of a series! Make sure to check out:

What is a Crystal, Anyway? (Electric Crystals, Part 1)

Unit Cells and Their Molecular Building Blocks (Electric Crystals, Part 2)

How do Crystals get their Shapes? (Electric Crystals, Part 3) 


 
SHARE THIS POST:

Related Posts

07/25
Supporting Image
Supporting Image
Ferroelectric hafnia

Ferroelectric materials generate electric fields that move charges around, just as a bar magnet produces a magnetic field that moves magnets around. Ferroelectric materials can be used for data storage to make electronics more energy efficient, but they don’t always play well with the silicon technology used in devices like phones and computers. HAFNIA TO THE RESCUE! Click to learn more.

0 0    

More Funsize Activities

05/19
Supporting Image
Supporting Image
Electric Crystals, Part 3

Students make paper models of crystal unit cells and build a large crystal structure together while reflecting on the role of symmetry in crystal formation. This lesson is part 3 of a 4-part student-driven, lecture-free series, in which students will do card sorts, build hands-on models, solve engineering design puzzles, and more!

0 0    
05/18
Supporting Image
Supporting Image
Electric Crystals, Part 2

Through hands-on activities using gumdrops and toothpicks, students will learn about unit cells that make up the repeating structures of crystals like table salt. This lesson is part 2 of a 4-part student-driven, lecture-free series, in which students will do card sorts, build hands-on models, solve engineering design puzzles, and more!

0 0    
11/30
Supporting Image
Supporting Image
Domains and Disks
by Shireen Adenwalla, Xiaoshan Xu

Magnets curve themselves into beautiful patterns called domains, which cannot be seen with the naked eye. Now that magnetic paint and nail polish are easily available, we can use magnets to create all kinds of magnetic patterns which we can see, photograph, erase and rewrite! Click to find out how YOU can paint with magnets!

2 2    
11/05
Supporting Image
Supporting Image
Light scattering and diffraction

Have you ever wondered how scientists can accurately measure the size of very small objects like molecules, nanoparticles, and parts of cells? Scientists are continually finding new ways to do this, and one powerful tool they use is light scattering. When an incoming beam of light hits an object, the light "scatters," or breaks into separate streams that form different patterns depending on the size of the object. This incoming light might be visible light, like the light we see from the sun, or it might be higher-energy light like X-rays. The light from commercial laser pointers, it turns out, is perfectly suited to measure the size of a human hair!

0 0    
05/08
Supporting Image
Supporting Image
The Visible Spectrum and Spectroscopes
by Wesley Sliger, Martin Centurion

Have you ever wondered why shining light on a glass of water causes rainbows to appear? Or noticed the colors that reflect from a CD or DVD? In this lesson, you will make an instrument called a spectroscope that can separate light into its hidden components. You will also be able to use the spectroscope to understand why different colored objects and light sources appear the way they do.

0 0    
02/12
Supporting Image
Supporting Image
Forming nanostructures

Self-assembly is the process by which individual building blocks—at the smallest level, atoms—spontaneously form larger structures. The structures they form depend on the size and shape of the building blocks, and on the conditions to which these building blocks are exposed. This can be demonstrated quite simply using breakfast cereal, or for more complex cases using specially prepared Legos.

0 0    
03/14
Supporting Image
Supporting Image
Chemical vapor deposition

Graphene is a two-dimensional material made from a single sheet of atoms, with outstanding mechanical, electronic, and thermal properties. It is a promising candidate to enable next-generation technologies in a wide range of fields, including electronics, energy, and medicine. This economical, safe, and simple lab activity allows students to make graphene via chemical vapor deposition in 30–45 minutes in a classroom setting.

0 0    
02/19
Supporting Image
Supporting Image
Making upside-down images

We can easily observe light with our eyes, and so it is one of the most familiar parts of the world around us. And yet, light often does amazing and unexpected things. Light travels in straight lines from the source to our eyes. This fact allows us to understand many of the cool things that light can do. In this lesson, we will observe how light creates mirages and shadows. And we will build a pinhole camera which makes things appear upside-down. We can understand the upside-down images by thinking about the straight line that the light took from the object to the screen.

0 0    

WRITE COMMENT

Go to Top