# Physical Science B – Lesson # 11 (2-24-2020)

Waves

### Unit:

Physical Science B – Unit 8 (Mr. Tyler Version)

### Objectives:

• Explain that waves transfer energy, not matter.
• Distinguish between mechanical and electromagnetic waves.
• Summarize the major properties and behavior of waves, including (but not limited to) wavelength, frequency, amplitude, speed, refraction, reflection and diffraction.

### Vocabulary/Definitions

amplitude: How far the medium (crests and troughs, or compression and rarefaction) moves from rest position (the place the medium is when not moving).

compression: When the particles of a longitudinal wave are close together.

compressional (longitudinal) wave: A wave in which the medium moves back and forth in the same direction as the wave.

crest: The highest point on a transverse wave.

diffraction: The bending of waves around an object.

electromagnetic wave: A wave that does not require a medium to travel, for example, it can travel through a vacuum. Also called an EM wave.

energy: The capacity to do work.

frequency: How many waves go past a point in one second. Measured in hertz (Hz).

mechanical wave: A wave that requires a medium to travel.

rarefaction : When the particles of a longitudinal wave are far apart.

reflection: When a wave bounces off a surface.

refraction: When a wave bends.

transverse wave: A wave in which the medium moves at right angles to the direction of the wave.

trough: The lowest point on a transverse wave.

wave: A disturbance that carries energy from one place to another.

wavelength: Distance between one point on a wave and the exact same place on the next wave.

### Engineering Connection

Engineers apply their knowledge of waves to design an array of useful products and tools, many of which are evident in our everyday lives. For example: microwave ovens, x-ray machines, eyeglasses, tsunami prediction, radios and speakers. Engineers must understand all the properties of waves and how waves can differ from one another in order to design safe and effective products. To predict how tsunamis will travel after a ocean earthquake, engineers must understand wave properties and how they travel. Engineers also use their understanding of wave properties when designing electronics—to separate different types of waves so that radios tune in to the right stations, or so your cell phone only picks up the calls that you want. Before designing a solution to a challenge, engineers conduct research and gather information as a crucial part of the engineering design process. Through this legacy cycle lesson, students begin to gather the knowledge necessary to come up with a solution to the engineering challenge outlined in lesson 1 of this unit.

### Warm Up:

Heads to Socrative.com and enter room name “A89559b4”

### Agenda:

Unit 8 – Introduction to Waves

Engineering Challenge:

You just got your first job. You are now a stock person in the new Food Lion. You show up for your first day of work excited and ready to prove how good a worker you are. The manager greets you and assigns your first task. He takes you back to the delivery entrance and you see cases and cases of apples sitting on the loading dock. The manager waves his hand over the entire mess, and says, “These need to be put into the cooler. Separate the boxes by apple type and put the Granny Smiths on the left side, the Golden Delicious in the middle, and the Red Delicious on the right. Then put some of each out in the store in the produce section.” Before you can ask any questions, an urgent summons for the manager comes over the intercom system and he rushes off. You look at the cases and see no labels on the boxes. “No problem,” you say to yourself. “I’ll just look in the boxes to see what’s what.” So you look in the boxes. However, you only see two different colors of apples, not three. The only identifying feature they have are numbers on stickers. Just as you are about to panic, another worker walks by. “How do you tell the difference between Granny Smith, Golden Delicious, and Red Delicious apples?” you ask him. He gives you a strange look and says, “The Granny Smiths are green, the Golden Delicious are yellow, and the Red Delicious are red. Duh!” You think to yourself: Why can’t I see three colors? Is it my eyes, or something else that affects how we are able to see? Can you apply engineering principles to design a device that could be used to help distinguish these three colors from one another?

Three key knowledge areas:

1. waves and wave properties,
2. light and the electromagnetic spectrum
3. Structure of the eye

Let’s start this task with what we already know. Why are we able to see? (Because there is light.) What is light? (It is a wave.) So, what is a wave? Well, we will learn the answer to that question today!

I will pass out an outline that will help you keep track of the important concepts explained as we talk about waves and wave properties.

Testing out our new knowledge.

Utilizing your new notes and understanding tackle the next piece of work on your own or with a partner if you chose.

Assignment -> Physical Science Unit 8 – Anatomy of a Wave

Template  -> Template – Printable – Graph Paper

### Lesson Source:

Website – TeachEngineering STEAM – Apples

Website – TeachEngineering STEM Curiculum K-12