Unit Plan 28 (Grade 8 Science): Intro to Waves—Properties & Patterns

Focus: Use mathematical representations to describe waves in terms of amplitude and wavelength and to show how wave patterns provide information about motion, energy, and signals.

Grade Level: 8

Subject Area: Science (Physical Science • Waves & Information)

Total Unit Duration: 5 sessions (one week), 50–60 minutes per session

I. Introduction

Students are introduced to waves as repeating patterns that transfer energy and information without transferring matter. They learn key features of simple transverse waves—crest, trough, amplitude, and wavelength—and practice using graphs and diagrams to describe wave patterns. Using ropes, springs, or digital simulations, students generate waves, measure their properties, and connect mathematical descriptions (numbers and symbols) to visual patterns. By the end of the week, students can interpret and create simple wave graphs, explain how changes in amplitude and wavelength affect a wave’s behavior, and describe how wave patterns can be used to represent and decode information.

Essential Questions

• What is a wave, and how is it different from the material it travels through?
• How do we describe waves using amplitude and wavelength, and what do those quantities tell us about the wave?
• How can graphs and diagrams of waves help us see patterns and relationships we might miss otherwise?
• In what ways can wave patterns be used to carry and represent information (like sounds, images, or digital signals)?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Define a wave as a repeating pattern that transfers energy and describe basic parts of a transverse wave (crest, trough, amplitude, wavelength).
2. Measure and calculate amplitude and wavelength from physical models (ropes/springs) and graphs (wave vs. position or time).
3. Use mathematical representations (tables of values, labeled graphs, simple equations) to describe waves in terms of amplitude and wavelength.
4. Compare waves with different amplitudes and wavelengths and explain how changes in these properties affect energy and pattern spacing.
5. Interpret wave patterns (e.g., repeating peaks, spacing between crests) to explain what information they can provide (such as distance, pitch, or encoded signals).
6. Construct a short written or visual explanation connecting wave graphs, measurements, and patterns to the standard’s language.

Standards Alignment — 8th Grade (NGSS-based custom)

• MS-PS4-1 — Use mathematical representations to describe waves in terms of amplitude and wavelength and to show how wave patterns provide information about the source and/or the medium.
  • In this unit, students generate, measure, and graph waves, then use numbers and patterns (e.g., repeated crests) to describe and interpret their properties.

Success Criteria — Student Language

• I can label the parts of a transverse wave and correctly use the terms amplitude and wavelength.
• I can measure amplitude and wavelength from a diagram or graph and record them using correct units.
• I can draw and interpret graphs of waves that show repeating patterns and clearly indicate amplitude and wavelength.
• I can compare waves (e.g., one with larger amplitude, one with shorter wavelength) and explain how they are different using numbers.
• I can describe how wave patterns (like evenly spaced peaks) can provide information about what is happening at the source or in the medium.