Day 1: Lesson 3: Light Waves

Day 1: Lesson 3: Light Waves

• Objectives: define light, describe light as an electromagnetic wave, explain how EM waves are formed, design a 3D model of EM waves
• Essential Question: What is light?
• Vocabulary: Light, Electromagnetic waves, Radiation

The Nature of Light

• Light is a type of energy that travels as a wave
• Sources of light include light bulbs, burning logs, candles, fireflies, and some fish
• Light is different from other waves (like sound or water waves) as it does not require a medium to travel through
• Electromagnetic (EM) waves can exist in empty space because electric and magnetic fields can exist there
• Light is an EM wave, composed of electric and magnetic fields

What patterns do you observe?

• Comparing mechanical transverse waves to light waves
• Light waves transfer energy, but don't require a medium

Electromagnetic Wave

• Electromagnetic waves are composed of oscillating electric and magnetic fields

Stages of EM waves Formation

• Vibrations of a charged particle disturb surrounding electric and magnetic fields
• These disturbances form EM waves
• The electric and magnetic fields are perpendicular to each other
• EM waves carry energy away from the charged particle

Group Activity: Design 3D Model of EM Waves

• Materials: Scissors, two sheets of hard paper, colored markers, ruler
• Instructions:
  • Draw two or three waves on each paper, using different colors to represent electric and magnetic waves
  • Waves should all be the same length (1 cm)
  • Cut half the paper from one side, but do not split the waves
  • Ensure waves are perpendicular to each other
  • The waves are connected and oscillating

Day 2: Lesson 3: Light Waves

• Objectives: identify different EM spectrum waves, explain the relationship between wavelength, frequency, and energy, compare/contrast different EM waves, relate EM spectrum to everyday life/modern technology
• Essential Question: What is light?
• The electromagnetic spectrum is a range of waves with varying frequencies and energies
• Different types of waves have various uses (communication, medical treatments)

Starter

• Draw EM waves (light waves) in your notebook, showing both magnetic and electric fields.

EM Spectrum

• The EM spectrum is a range of waves with different frequencies and energies
• Types of waves: Radio, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays

Relationship between Wavelength, Frequency, and Energy

• Watch a video to understand the relationship between wavelength, frequency, and energy in EM waves
• Short wavelength = High frequency = high energy
• Long wavelength = Low frequency = low energy

From the Video

• Discussion questions about the various EM waves and their uses:
  • How do radio waves help with communication?
  • Why is visible light essential for life on Earth?
  • How can ultraviolet light both help (vitamin D) and harm (sunburn)?
  • How do X-rays help doctors?

Types of EM Waves (Summary)

• Radio waves: Longest wavelength, lowest frequency energy, communication signals (TV, radio, cell phones)
• Microwaves: Shorter than radio waves, microwave ovens, satellite communications
• Infrared radiation: Just below visible light in frequency, heat lamps, night vision goggles
• Visible light: The only part of the EM spectrum we can see, rainbow colors (ROYGBIV), sunlight
• Ultraviolet radiation: Higher frequency than visible light, below X-rays, sunburns, sterilization of medical equipment
• X-rays: Higher energy than UV, medical imaging
• Gamma rays: Shortest wavelength, highest energy, cancer treatment, emitted by radioactive materials

Check Your Understanding

• Compare and contrast the different EM wave types and relate them to everyday life and modern technology (Radio, Microwave, Infrared, Visible Light, UV, X-rays, Gamma rays)
  • Each student should write at least one use for at least 2 waves

Day 3: Lesson 2: Light Waves and Color

• Standards:
  • MS-PS4-1: Use mathematical representations to describe a simple wave model. Address how amplitude of waves relates to energy in a wave.
  • MS-PS4-2: Develop and use a model that describes how waves are reflected, absorbed, or transmitted.

Objectives

• State that color corresponds to certain wavelengths and frequencies of light
• Describe the colors in rainbows
• Explain the order of rainbow colors
• Compare how different colors of light waves are arranged

Vocabulary

• Color, white light, visible light

Group Work (Research Skills)

• Instructions:
  • Sit in a group
  • Choose a role
  • Search for information
  • Present the information
• Questions:
  • What is visible light?
  • How is visible light separated into colors?
  • What separates white light into different colors?

Light Waves and Color (Detail)

• Light travels as a wave; wavelengths are invisible to the human eye
• Visible light is the range of wavelengths visible to human eyes, comprised of a continuous spectrum of colors
• Colors correspond to certain wavelengths & frequencies
• Our eyes interpret these different wavelengths as different colors
• A prism separates white light into a spectrum of colors

What determines the color of light?

• Sunlight contains all visible light wavelengths
• Wavelength/frequency of visible light determines its color

Checking Understanding

• Color corresponds to a certain wavelength and frequency of light
• List the wavelength and frequency for each color