# 6.2.3.1 Waves

6
Subject:
Science
Strand:
Physical Science
Substrand:
Energy
Standard 6.2.3.1

Waves involve the transfer of energy without the transfer of matter.

Benchmark: 6.2.3.1.1 Properties of Waves

Describe properties of waves, including speed, wavelength, frequency and amplitude.

Benchmark: 6.2.3.1.2 Energy Transfer in Sound

Explain how the vibration of particles in air and other materials results in the transfer of energy through sound waves.

Benchmark: 6.2.3.1.3 Wave Properties of Light

Use wave properties of light to explain reflection, refraction and the color spectrum.

## Overview

Standard in Lay Terms

MN Standard in Lay Terms

Energy moves from one medium to another by waves without any loss or gain of matter.  These waves vary in speed and size depending on the type of energy being transferred.

Sound is energy and moves by waves that vibrate particles of matter as it moves from one place to another.  That matter for us humans is the molecules of gas in the air around us, but sound moves through solid and liquid matter in a similar fashion.

Light also travels by wave and these wave can bounce off matter (reflection) or slow down as they move through matter (refraction).  The different sizes of waves in that make up white light are the colors of the spectrum of that light.

Big Ideas and Essential Understandings

Big Idea

Wave motion -- Light and sound travel in waves.  Different sounds have different wavelengths and different parts of the light spectrum have different wavelengths.

Light--Light is made of many different colors, of varying wavelengths, different energies.  The eye cannot detect all wavelengths of light energy.

Vibrations--Vibrations create waves that move away from the original source.

Benchmark Cluster

MN Standard Benchmarks

6.2.3.1.1  Describe the properties of waves, including speed, wavelength, frequency, and amplitude.

6.2.3.1.2  Explain how the vibration of particles in air and other materials results in the transfer of energy through sound waves.

6.2.3.1.3  Use wave properties of light to explain reflection, refraction and the color spectrum

The Essentials

A quote, cartoon or video clip link directly related to the standard.

6.2.3.1:

NASA eClips has many excellent video clips that connect to multiple standards and benchmarks.  The eClips site allows teachers to search for videos specific to the subject matter.  The "waves" eClip might be used after students become familiar with the various types of waves found in nature.

Go to this site and search "waves."

Correlations

NSES Standards:

K-4, Light, Heat, Electricity, and Magnetism

Light travels in a straight line until it strikes an object. Light can be reflected by a mirror, refracted by a lens, or absorbed by the object.

5-8, Transfer of Energy

Energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei, and the nature of a chemical. Energy is transferred in many ways.

Light interacts with matter by transmission (including refraction), absorption, or scattering (including reflection). To see an object, light from that object-emitted by or scattered from it-must enter the eye.

Electrical circuits provide a means of transferring electrical energy when heat, light, sound, and chemical changes are produced.

The sun is a major source of energy for changes on the earth's surface. The sun loses energy by emitting light. A tiny fraction of that light reaches the earth, transferring energy from the sun to the earth. The sun's energy arrives as light with a range of wavelengths, consisting of visible light, infrared, and ultraviolet radiation.

9-12, Interactions of Energy and Matter

Waves, including sound and seismic waves, waves on water, and light waves, have energy and can transfer energy when they interact with matter.

AAAS Atlas:

Volume 1, Motion:  Waves, p. 62-63

Benchmarks of Science Literacy:

Energy can be transferred from one system to another (or from a system to its environment) in different ways: 1) thermally, when a warmer object is in contact with a cooler one; 2) mechanically, when two objects push or pull on each other over a distance; 3) electrically, when an electrical source such as a battery or generator is connected in a complete circuit to an electrical device; or 4) by electromagnetic waves. 4E/M2*

Thermal energy is transferred through a material by the collisions of atoms within the material. Over time, the thermal energy tends to spread out through a material and from one material to another if they are in contact. Thermal energy can also be transferred by means of currents in air, water, or other fluids. In addition, some thermal energy in all materials is transformed into light energy and radiated into the environment by electromagnetic waves; that light energy can be transformed back into thermal energy when the electromagnetic waves strike another material. As a result, a material tends to cool down unless some other form of energy is converted to thermal energy in the material. 4E/M3*

Energy appears in different forms and can be transformed within a system. Motion energy is associated with the speed of an object. Thermal energy is associated with the temperature of an object. Gravitational energy is associated with the height of an object above a reference point. Elastic energy is associated with the stretching or compressing of an elastic object. Chemical energy is associated with the composition of a substance. Electrical energy is associated with an electric current in a circuit. Light energy is associated with the frequency of electromagnetic waves. 4E/M4*

Light and other electromagnetic waves can warm objects. How much an object's temperature increases depends on how intense the light striking its surface is, how long the light shines on the object, and how much of the light is absorbed. 4E/M6**

Common Core Standards

Math:

Expose students to formulas associated with frequency and waves.

6.EE.2. Write, read, and evaluate expressions in which letters stand for numbers.

Social Studies and Language Arts:

Examine the impact that wave knowledge has made on technology advancements.  Research a piece of technology that depends on waves.

RST.6-8.4.       Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 6-8 texts and topics.

## Misconceptions

Student Misconceptions

The majority of elementary students and some middle-school students who have not received any systematic instruction about light tend to identify light with its source (e.g., light is in the bulb) or its effects (e.g., patch of light). They do not have a notion of light as something that travels from one place to another. Middle-school students often accept that mirrors reflect light but, at least in some situations, reject the idea that ordinary objects reflect light (Guesne, 1985; Ramadas & Driver, 1989).

"When students are being introduced to waves, they may believe that:

• Waves transport matter.
• There must be a medium for a wave to travel through.
• Waves do not have energy.
• All waves travel the same way.
• Frequency is connected to loudness for all amplitudes.
• Big waves travel faster than small waves in the same medium.
• Different colors of light are different types of waves.
• Pitch is related to intensity.

When students are introduced to light, they may believe that:

• Light 'just is" and has no origin.
• Light is a particle.
• Light is a mixture of particles and waves.
• Light waves and radio waves are not the same thing.
• In refraction, the characteristics of light change.
• The speed of light never changes.
• Rays and wave fronts are the same thing.
• There is no interaction between light and matter.
• The addition of all colors of light yields black.

Olenick, Richard. "Misconceptions in Teaching Introductory Physics." Comprehensive

Conceptual Curriculum for Physics. National Science Foundation, 16 07 2009. Web. 27 Dec 2010.

## Vignette

Over the last few class periods, Ms. K's class has just been working on a number of investigations with the reflection and refraction of light.  A number of students have commented on observing a small rainbow occasionally as they were making light "bend" through dishes of water.  She adapts the GEMS unit, Color Analyzers, to help the students discover why the rainbow appears and some of the properties of the spectrum (6.2.3.1.3)

The next day, Ms. K turns off the classroom lights and turns on a single lamp in the center of the room. She asks her students examine to examine the light's energy and try to describe it, especially its color.  She then asks the students to put on diffraction grating glasses and look at the light.  They are asked to record their observations in their science notebooks, paying close attention to the colors observed, their location in relationship to each other, and size comparisons.

Lights are turned back on and students are asked to share their observations with each other.  Ms. K leads a whole group discussion on what they saw.  The students are clearly excited to share what they saw and describe the colors in detail.  She asks the students where the colors came from.  Many think that the colors are on the glasses themselves, so using an overhead projector, they project the colors onto a screen.  At this point the students begin to hypothesize that something is happening to the light as it passes through the glasses.

Ms. K closes the lesson by explaining that the light is made of many colors called a spectrum, that the diffraction grating spreads the light out so one can see the component colors.

The next day, students come into the room and the word light is written on the white board in yellow marker.  The students are asked to put on a different set of glasses this time, ones with a red filter, and look at the message.

"It disappears!"

"Does it really disappear?  Or can you just not see it?" asks Ms. K.  "Why can't you see it?  Think about what we've learned about how light behaves when it hits something like the white board?"

The students take the glasses off and Ms. K writes in a purple and blue marker on the board.

"It turns black!"

"Again,"  says Ms. K, "does it turn black, or does it look black through the red filter?"

Through the discussion, Ms. K gets the students to explain how the yellow from the spectrum can reach their eyes, because it gets absorbed in the red filter.  They explore other filters with other colored writing and see if they have any effect.

The students spend the next day designing secret messages on white paper, surrounded by a number of colors and patterns, that seems to show up when looked through with the red filter due to all of the yellow, red and orange components "disappearing."

## Resources

Instructional Notes

Suggested Labs and Activities

Selected activities

6.2.3.1.3:

Color Analyzers by GEMS offers a number of labs on light, spectra and color (info found at this site).

6.2.3.1.1, 6.2.3.1.2, 6.2.3.1.3:

Energy Transfer: Waves, Sound, and Light by Lab Aids offers comprehensive and middle school appropriate literature and labs that align with the standard and benchmarks.  The info is found at this site.

Instructional Resources

Instructional Suggestions/Options

Benchmark 6.2.3.1.1:  Describe the properties of waves, including speed, wavelength, frequency, and amplitude:

Provide each group of two students with a "slinky."  Tell the students to stretch the slinky  across the floor or table, and allow them to work together to make small, medium, and large "s-waves" with the slinky.  After students have had enough time to explore, stop the group and generate a list of characteristics that students noticed about the waves.  The list might include items like, "when I moved my end of the slinky slowly, the wave moved slowly," etc.

After a list has been generated, introduce one wave property at a time, and relate it to the characteristic that students noticed as they explored.  Students can write the properties in a two-column chart in the science notebooks.  The left side of the chart should list the wave property.  The right side should include a sketch and definition.

To review, have the students return to their slinkies.  Call out a property and give the students time to verbally review the definition with a partner.  Then the students should "act out" the property with the slinky.

Sound Waves:

Collaborate with music teachers to assure that common language is being used and reinforced in both content areas.

"Students should be able to understand the mechanism by which different waves transfer energy.

Students should be able to describe mechanical and electromagnetic waves and use their properties to explain natural phenomena and technological applications.  (i.e. thunder before lightning,  antennas for cell phone transmission and reception, noise cancellation, musical instruments, decibel-hearing loss, Doppler-radar, echo location / sonography and ultrasound.)"

"Enduring Understandings and Essential Questions for Physics." Midland Public Schools. Midland Public Schools, n.d. Web. 27 Dec 2010.

New Vocabulary

Vocabulary/Glossary

• Amplitude: the height of a wave, measured from its midpoint to its crest.
• Crest: the highest point of a wave.
• Energy: capacity for doing work.
• Frequency: the number of waves that pass through a given point in a given amount of time.
• Pitch: how high or how low a sound is perceived to be.
• Reflection: the change of direction of a wave when it strikes a boundary.
• Refraction: the turning or bending of a wave when it passes through a medium.
• Spectrum: the arrangement of forms of radiation separated according to a given property such as wavelength.
• Speed: the rate of change of an object's position measured by distance/time.
• Trough: the lowest point of a wave.
• Vibration: a periodic back and forth movement of particles.
• Wavelength: the distance between one crest or peak of a wave to the next crest or peak.
Technology Connections

6.2.3.1.1:

Use this activity to discuss the vocabulary and properties associated with waves:

6.2.3.1.2:

Use this activity to demonstrate how changing a variable of a sound wave changes the sound produced:

Sound

Cross Curricular Connections

Use math tools and formulas to calculate the incident angle and angle of reflection, wave speed, wave frequency, etc.

Connect with music teachers to assure that common language is being used in both content areas.

References

6.2.3.1.3

This activity demonstrates properties of light waves and guides students toward an understanding of why the sky is blue.

6.2.3.1.3

This activity demonstrates properties of light waves.  Light is reflected between two sheets of plexiglass and rainbow patterns become visible in the glass.

6.2.3.1.3

This activity demonstrates how waves diffract, or bends, around edges.

6.2.3.1.3

This activity demonstrates the color spectrum associated with light.

6.2.3.1.3

This activity uses a glue stick and a flashlight to demonstrate how light waves scatter in the atmosphere to create colorful sunsets and a blue sky.

## Assessment

Assessment of Students

Formative:

Make a list of objects you think can vibrate to produce sound.

Imagine yourself standing close to a mirror at eye level.  Think about how much of your face you are able to see.  Now imagine taking 10 steps back from the mirror.  How much of your face can you see this time?

Where do waves come from?  How are sound waves similar to waves in water?  How are they different?

Summative:

Application:

"Draw a wave that represents a loud, high-pitched sound.  Label the wavelength and amplitude.

Draw a wave that represents a quiet, low-pitched sound. Label the wavelength and amplitude.

Draw a wave that represents a loud, low-pitched sound. Label the wavelength and amplitude.

When lightning strikes, both light energy and sound energy are produced at the same instant.  Explain why you usually see the lightning before you hear the thunder."

Energy Transfer: Waves, Loud, and Light. Cat. No. 211. Ronkonkoma, NY: Lab-Aids, 2009. 6-7. Print.

Evaluating:

How do you know that waves carry energy?

Creating:

Explain how knowledge of waves helps us understand our world and create technologies that make life better.

Assessment of Teachers

Waves transfer energy from one place to another.  Do waves displace the particles of a medium when they are in motion?

Is it most appropriate for students to learn about waves before or after they have been introduced to the term "energy?"

How do the lessons you have created regarding waves relate to the transfer of energy lessons that students have experienced?

## Differentiation

Struggling Learners

Struggling and At-Risk

Provide students with multiple hands-on opportunities to create, compare, and contrast different types of waves.  Insert short reading activities between the lessons to identify key vocabulary and summarize major concepts.

English Language Learners

Provide an experience with waves before identifying and labeling vocabulary terms.

For example, when teaching "reflection," provide students with a paper copy of a protractor and a list of angles (15, 30, 45, 60, 75, and 90 degrees).  Have students place the 0 degree angles against the back wall of the classroom.  For each angle in the list, students should roll the marble toward the center of the protractor on the line that represents that angle.  Repeat two times.  Observe the angle at which the marble bounces off the wall.  Record the data.

Once students recognize the pattern in the results, explain the term "reflection."

While developing Energy concepts with ELL students make sure to:

• Illustrate and diagram concepts with vocabulary on the board during discussion
• Give step-by-step directions for labs
• Prepare word walls or glossary sheets with illustrated vocabulary for students to easily access
• Summarize discussion and learning more frequently
• In setting up groups, pair non-native with native speakers.
• Make connections to the students' out of school experiences
• Vary instructional delivery to include picture books, video, etc.
Extending the Learning

Students might create an experiment in which they demonstrate the reflection and refraction of light, using household objects.

Multi-Cultural

Introduce the concept of waves by showing students water waves.  Explain that a tsunami is a large, powerful water wave.  Use this website to help students research the causes of this enormous wave.

Special Education

The study of waves can be difficult for students, because waves are often not seen.  Begin the study by showing students examples of water waves.  Connect the "wave" vocabulary and concepts studied in class to the water waves.