Unit 3 Waves
I am learning about the properties of waves.
I can describe the frequency, wavelength, & amplitude of waves.
I can explain how mechanical waves are different from electromagnetic waves.
I am learning about the behavior of waves.
I can explain how waves travel: reflection, absorption, transmission, and refraction.
I can describe how various media affect the way waves travel by reflection, absorption, transmission, and refraction.
What Are Waves?
Waves are disturbances that transfer energy from one place to another.
There are two main types: mechanical waves and electromagnetic waves.
Mechanical Waves require a medium (a substance) to travel through. Sound is a mechanical wave—it needs air, water, or another material to move. This is why there's no sound in space (there's no air for sound waves to travel through). Water waves and earthquake waves are also mechanical waves.
Electromagnetic Waves (like light) don't need a medium. They can travel
through empty space. This is how sunlight reaches Earth from 93 million miles away!
How Waves Interact with Materials When a wave hits a material, three things can happen:
1. Reflection occurs when a wave bounces off a surface. When you look in a mirror, light waves reflect off the shiny surface. Sound waves reflect too—that's what causes an echo when you shout in a canyon.
2. Absorption happens when a material takes in wave energy instead of reflecting it. Dark materials absorb more light than light-colored materials. That's why wearing a black shirt on a sunny day makes you feel hotter than wearing white. The black fabric absorbs light energy and converts it to thermal energy.
3. Transmission occurs when waves pass through a material. Clear glass transmits light—you can see through it. But frosted glass transmits light differently, scattering it so you can't see clearly through it.
Light and Sound Behave Differently
Light can travel through space (no medium needed), but sound cannot. Light travels in straight lines except when it hits surfaces between different transparent materials - like when light bends going from air into water (refraction). This bending makes a straw in a glass of water look broken!
The frequency (number of waves per second) and color of light affect how materials interact with it. Some materials reflect red light but absorb blue light. This is why objects appear different colors.
Unit 3 Waves - Reading Informational Text
Types of Waves: Mechanical and Electromagnetic online article
This is a great website for this unit. https://www.ducksters.com/science/physics/ Below are more specific topics related to what we are learning. At the bottom of each page, you'll also find an online quiz.
Waves and Sound
Intro to Waves
Properties of Waves
Wave Behavior
Basics of Sound
The Sound Wave
Light and Optics
Intro to Light
Light Spectrum
Light as a Wave
Electromagnetic Waves
Lenses
Properties of waves:
The behavior of waves is different depending on the object they encounter. Below are examples of the behavior of light waves:
When sound waves hit a surface, they do three things: reflect, absorb, or transmit. Reflection bounces sound back. Absorption traps sound and converts it to heat. Transmission passes sound through to the other side. These behaviors depend on the material, frequency, and density.
