Teacher Guide

# ChromaDepth Glasses

## Experimenting with wave properties of light

What is wave diffraction? Wave refraction? Name examples of wave diffraction and refraction you see in real life. How can ChromaDepth possibly play into new technologies?

This resource was originally published in PhysicsQuest 2023: Making Waves.

This is the teacher guide for this lesson. A student-focused guide to assist learners as they perform the activity is available.

View the student guide: ChromaDepth Glasses

What is wave diffraction? Wave refraction? Name examples of wave diffraction and refraction you see in real life. How can ChromaDepth possibly play into new technologies?

• ChromaDepth glasses
• Colorful fabric, images, etc. (We’ve found that bright primary colors on dark backgrounds work best.)
• Black paper and colorful gel pens, paint markers, or similar drawing implements to create ChromaDepth art

Students start by exploring different light sources using ChromaDepth glasses. Encourage students to look at different colorful fabrics, objects, posters on your walls, or Google “Chromadepth art,” and look at various pictures online that give a good 3D effect. Then they can create “ChromaDepth art” — drawing with brightly-colored gel pens or paint markers on black paper. Finally, encourage students to think about real-life scenarios where ChromaDepth technology could be used.

• Total time
30 - 45 minutes
• Education level
Grades 5 - 9
• Content Area
Waves
• Educational topic
Waves, features of waves, wave terminology

Watch this video from Little Shop of Physics for an overview of the experimental setup and the science behind the phenomenon.

The lenses of ChromaDepth glasses contain a very fine series of slits. Light passing through these slits will get spread out. In formal physics jargon, the lenses act as diffraction gratings: they diffract (spread out) light that passes through them. It’s worth noting that the grating in ChromaDepth glasses has a unique structure — the fine structure in these lenses is a bit different than a normal diffraction grating. The angle of diffraction depends on the wavelength (color) of the light.

The overall effect we are interested in is that the glasses diffract (bend) different wavelengths (colors) of light to different angles. The glasses bend red light to a greater angle than blue light (in-between colors, like green, are bent to in-between angles). Most people’s brains will interpret this difference in angles to mean that red areas are “floating” above a surface and that blue areas are “sinking” into it.

Optical devices (like lenses, mirrors, prisms, diffraction gratings, etc.) use reflection, refraction, or diffraction to move light around. The optics found in ChromaDepth 3D glasses, combine refraction and diffraction to make thin optics that act like thick glass prisms; it’s like having a super compact version of a glass prism!

Key terms

These are the key terms that students should know by the end of the lesson. They do not need to be front loaded. In fact, studies show that presenting key terms to students before the lesson may not be as effective as having students observe and witness the phenomenon the key terms illustrate beforehand and learn the formalized words afterward. For this reason, we recommend allowing students to grapple with the experiments without knowing these words and then exposing them to the formalized definitions afterward in the context of what they learned.

However, if these words are helpful for students on an IEP, ELL students, or anyone else who may need more support, please use at your discretion.

• Diffraction: : Slight bending of a wave as it passes around the edges of an obstacle
• Refraction: : The bending of a wave as it travels from one material to another
Objective

Students will use ChromaDepth glasses which bend light of different wavelengths by different amounts. Students will experiment by looking at different objects with the glasses on, create ChromaDepth art, and brainstorm possible applications of ChromaDepth technology.

It is important to understand that student goals may be different and unique from the lesson goals. We recommend leaving room for students to set their own goals for each activity.

Before the experiment
• Ask the students to wear brightly colored clothing for the day of the experiment.

• Watch this video from Little Shop of Physics for an overview of the experimental setup and the science behind the phenomenon.

• Ask any or all of the following set-up questions:

1. Have you ever stuck your arm in a swimming pool and noticed how it appears “broken” at the boundary between the water and the air above?
1. Maybe you’ve seen something similar with a drinking straw sitting in a glass of water.
2. Why do you think that happens?
2. How about the rainbow effect you can see when looking at the back of a CD or DVD disc?
1. What causes those rainbow colors to appear?

• Tell students that the experiment they are about to do will help them explore these properties of light waves.

Setting up
• It is often helpful to have some fabrics or images on hand that you know will give a good effect when observed through the glasses; you’ll want to look for bright primary colors (reds, greens, and blues, though bright yellows and pinks also usually work) on dark backgrounds.

• Hand out one pair of ChromaDepth glasses per student.

During the experiment
• These glasses lend themselves well to open-ended inquiry. Just put on a pair of glasses and explore.

Note that the effect will be quite strong and apparent for most students but may be much weaker for some.

• Have students create “ChromaDepth art” — drawing with brightly-colored gel pens/paint markers on black paper. If you’re having trouble making this work with the gel pens, note that creating thicker lines and putting different-colored lines adjacent to one another tends to improve the effect.

• Introduce the PhysicsQuest 23: Making Waves Physics Career and Concept Map (at bottom of page) and allow students to read through and discuss the careers that use this content. Extend their thinking with research about these careers if time allows.

Teacher tip

A great way to start any physics-related unit is with the STEP UP Careers in Physics lesson. This lesson covers careers one can do with a physics degree, particularly those that help solve societal problems. It helps students assess their personal values in relation to a career in physics, examine profiles of professionals with physics degrees, and envision themselves in a physics career.

Suggested STEP UP Everyday Actions to incorporate into the activity:

• When pairing students, try to have male/female partners and invite female students to share their ideas first.
• As you put students into groups, consider having females or students from underrepresented backgrounds take the leadership role.
• Take note of female participation. If they seem to be only receiving direction and following along, elevate their voice by asking them a question about their experiment.

Consider using whiteboards so students have time to work through their ideas and brainstorm before saying them out loud.

As students experiment, roam around the room to listen in on discussion and notice experiment techniques. If needed, stop the class and call over to a certain group that has hit on an important concept.

Consider using the RIP protocol (Research, Instruct, Plan) for lab group visits and conferring.

Consider culturally responsive tools and strategies and/or open-ended reflection questions to help push student thinking, evidence tracking, and connections to their lives.

Conclusion
• After experiencing how ChromaDepth glasses create a 3D effect by diffracting and refracting the light, creating the effect of red features “floating” and blue features “sinking,” ask the students to think of possible applications of this technology in real life.

• Have students make a poster or other form of representation of their idea.

• Set the posters up around the classroom, on the walls, or on tables.

• Have small groups of students travel from station to station together, looking at others’ ideas.

• You can have students respond using sticky notes with questions or wonderings.

• Real world connections:
• Based on what you learned in this activity, which of the following images is an example of reflection, refraction, and diffraction? (Suggested photos below)
• Suggestions for drawing, illustrating, and presenting content in creative ways:
• Engineering and design challenges connected to the content:
• How could you use the properties of lenses and mirrors to move around a beam of light? Brainstorm what kinds of systems might use this type of technology and how you can use it to solve a problem.
• If engineering challenges have a time constraint, students are allowed to keep iterating and developing their ideas outside of class time and continue to participate in the challenge at a later date
• Watch this Listen to Light video and see what lasers sound like!

### Sign up for Physicists To-Go to have a scientist talk to your students.

Sign up for Physicists To-Go to have a scientist talk to your students.

### STEP UP Women in Physics lesson

STEP UP Women in Physics lesson: Introduces the underrepresentation of women in physics and the role of implicit bias and cultural stereotypes. Helps students examine the conditions for women in physics and discuss gender issues, gendered professions, and personal experience to neutralize the effect of stereotypes and bias.

• MS-PS4-1
Use mathematical representations to describe a simple model for waves that includes how the amplitude of a wave is related to the energy in a wave.
• MS-PS4-2
Develop and use a model to describe how waves are reflected, absorbed, or transmitted through various materials.
• MS-PS4-3
Integrate qualitative scientific and technical information to support the claim that digitized signals are a more reliable way to encode and transmit information than analog signals.

### Credits

Created by Cherie Bornhorst, MEd, and Little Shop of Physics along with Nicole Schrode, MEd, and Claudia Fracchiolla, PhD, of APS Public Engagement

Reviewed by Summer Chrisman, MEd, Tamia Williams, MSt, Chris Irwin

Extensions by Jenna Tempkin

Formatted by Sierra Crandell, MEd, partially funded by Eucalyptus Foundation

PhysicsQuest © 2023 by American Physical Society is licensed under CC BY-NC 4.0

### License

1. Attribution — You must give appropriate credit , provide a link to the license, and indicate if changes were made . You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
2. NonCommercial — You may not use the material for commercial purposes

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