Wave Behavior

Wave Behavior

By: Ann Paxton

Lesson Goals:

At the end of the lesson, students will be able to:

• describe reflection, refraction and diffraction
• categorize examples of wave behavior in their world
• construct patterns of wave interference
• Explain the concepts of constructive interference and destructive interference

Checklist for this lesson

• Complete vocabulary practice in Quizlet
• Read book pages 5-8
• Complete the VoiceThread assignment
• Read book pages 10-12
• Complete the hands on activity described on page 13 of the book
• Complete the assignment described on page 14

You can download a printable copy of the checklist by clicking HERE

As you read through the lesson, vocabulary words will be linked to the glossary.  You also have the option to go practice the vocabualry words for this lesson.  Click HERE to go to your Quizlet for this lesson. 

Waves interact with matter in different ways.  When waves travel through a medium, they are affected by this medium in different ways.  In addition, waves will interact with each other.  Let's explore the ways waves interact with media and other waves. 

Reflection  occurs in many types of waves--including sound, light, seismic, and water waves.  Have you ever yelled into a canyon and heard your voice return?  This is called an echo.  Echos are examples of reflection.  The sound waves from your voice strike a canyon wall.  Instead of entering the wall, the sound waves move back toward you.  In the case of reflection, the wave remains in one medium instead of entering a new one.  Reflection is when a wave reaches the boundary between two media and some, or all, of that wave bounces back into the first medium. 

Refraction  is the change in direction of a wave due to a change in wave speed.  Any type of wave can refract when it moves from one medium to another.  In the image below, the straw appears bent because of the bending of light as it moves through different media.  The media the light has to travel through are the air, the glass and water.  The change in wave speed results in you seeing a bent straw.

You can hear your mother yell for you even if she is another room and out of your line of sight.  Why is this?  Waves have the ability to spread out and travel around obstacles.  This is called diffraction .  Diffraction can also occur when a wave passes through an opening in an obstacle-like a water wave traveling in between two sand bars.  All waves are diffracted, but some diffract better!  Sound waves diffract better than light waves.  This is why you can hear someone around a corner but not see them!

Let's learn more about diffraction by watching this video. 

For our assignment, we will once again be using voice thread.  Please click HERE to go to the correct voicethread.

Think about what will happen if you throw two pebbles into a still pond.  The pebbles will create waves.  As these waves move away from their source, they will interact with one another.  These interactions will affect the amplitude of the wave. Interference is the interaction between waves when they meet.  There are two types of interference; constructive interference and destructive interference.

Constructive interference is the adding of waves.  This type of interference happens when a wave crest meets another wave crest or a wave trough meets another wave trough.  In constructive interference, the amplitudes are added together. The result is a wave with a larger amplitude. 

Destructive interference  is the subtraction of waves.  This type of interference occurs when wave crests meet wave troughs.  When destructive interference happens, the amplitude of the resulting wave is smaller than that of the origional waves. 

Let's learn more about wave interaction.  In this simulation, you will be able to manipulate different factors to visualize different types of wave interference--both constructive and destructive. 

Set your simulation to these specifications:

• pulse
• loose end
• zero (0) damping

Now, start one wave by moving the pulse end.  Start a second wave.  Watch what happens.  You can play the simulation in slow motion and pause to see wave interference.  You can also play the simulation in a 'step by step' mode. 

Click HERE to go to the simulation. 

For this lesson, you will complete the Ripple Tank Gizmo in Explore Learning. 

Remember the following log in information:

Username: UCA657             Password: pen657

As always, download the worksheet from our classroom in Explore Learning. You will e-mail the worksheet to your teacher when you have completed the assignment. You can also make a video of you completing the lab instead of completing the worksheet.

Click HERE to go to the website. 

All references are located in part 2 of the final project.