DAY 144
Zoom Meeting Agenda 11:00-11:30
1. Welcome
2. Goals
3. Warm-Up
4. 142A: Waves Guided Reading
- answers posted early this afternoon
5. Phet Wave Lab
- analyzing how changing the amplitude affects frequency
6. 144A: Wave Problem Solving
GOALS: SWBAT...
1. Memorize symbols for wave frequency, period, and wavelength
2. Recognize that wavelength is inversely proportional to frequency
3. Solve math problems to find wave speed, wavelength, and frequency
WARM-UP 144
Recall that sound is a mechanical wave.
1. TRUE or FALSE: In order for Xochitl to hear Sharkeisha , air molecules must move from the lips of Sharkeisha to the ears of Xochitl.
2. How does the sound move from Sharkeisha to Xochitl?
CLASSWORK
1. #144A: Wave Speed and Frequency: Notes & Problem Solving
Today we'll practice relating frequency and wavelength. You should notice that they are (directly/inversely(?)) proportional.
Wave demo - .5 waves ---> 1.5 waves
Example:
#1: An ocean wave of wavelength 1.2 m is traveling at 3.5 m/s. What is the frequency?
-What are the symbols for frequency, period, speed, and wavelength?
-How can we connect the speed equation we already know (speed=distance/time) to waves?
-The problem ends with a unit of 1/s. One what over seconds? Or...one what per second?
Solve each of the following using GUESS. Page 2, #2-8
LINK ---> https://drive.google.com/file/d/0B-AiPYEb3nFVT21US202cVFQbXM/view
HINTS:
#2 & #5: consider 17-19 from last weeks Guided Reading (below(
17. A complete back and forth vibration is one cycle. If it occurs in one second, the frequency is one vibration per second or one cycle per second.
18. The unit of frequency is called the hertz (Hz). A frequency of one cycle per second is 1 hertz, two cycles per second is 2 hertz, and so on.
19. Higher frequencies are measured in kilohertz (kHz– thousands of hertz), and still higher frequencies in megahertz (MHz– millions of hertz) or gigahertz (GHz– billions of hertz).
#3: Why is the mention of "echo" important?
2. #144B: Waves: Check Your Understanding
Answer the four questions below. Use last week's Homework reading to assist (link is here --> LINK).
1. Curly and Moe are conducting a wave experiment using a slinky. Curly introduces a disturbance into the slinky by giving it a quick back and forth jerk. Moe places his cheek (facial) at the opposite end of the slinky. Using the terminology of this unit, describe what Moe experiences as the pulse reaches the other end of the slinky.
2. Mac and Tosh are experimenting with pulses on a rope. They vibrate an end up and down to create the pulse and observe it moving from end to end. How does the position of a point on the rope, before the pulse comes, compare to the position after the pulse has passed?
3. Minute after minute, hour after hour, day after day, ocean waves continue to splash onto the shore. Explain why the beach is not completely submerged and why the middle of the ocean has not yet been depleted of its water supply.
4. A medium is able to transport a wave from one location to another because the particles of the medium are ____.
a. frictionless
b. isolated from one another
c. able to interact
d. very light
1. Answers to 144A are below.
1. 2.9 waves/s
2. 0.7 m
3. a. 1500 m b. 770 m
4. 4 m
5. 0.04 m
6. T = 13 s f = 0.077 waves/second
7. 2 x 1020 waves/second
8. 0.03 waves/second
2. Answers to 144B are below
LINK (scroll to the bottom of the page for problems and links to answers)
3. Phet Waves Lab is due electronically via Schoology tonight 11:59pm
4. 133A: Basic Waves (Slinky) Lab
Read ahead, as we'll be learning via this lab Wednesday
LINK
GOALS: SWBAT...
1. ...describe how a change in physical properties of a wave affects its sound.
2. ...memorize the speed of light
3. ...define a light-year
4. ...explain polarization
WARM-UP
1. Choose the right answers: Sound is a(n) [electromagnetic] [mechanical] [transverse] [longitudinal]
2. What two things are necessary for a sound to be made?
3. Which two frequencies could I combine to make a sound with 5 beats per second?
CLASSWORK
1. 144A: Sound Stations Lab
Share the lab with me. Title: P1 - Sound Stations Lab - Your Name
Read the entire lab, includeing conclusion questions
Complete in class, rotating through all four stations.
4 min per station
Lab LINK
2. 144B: Guided Reading: Light is a Wave
Guided Reading: LINK
Textbook Reading: LINK
HOMEWORK/LEARNING AT HOME
1. Complete 144B Guided Reading to prepare for Tomorrow (Thursday). Complete the entire assignment correctly, and get bonus HW points :)
2. 144A Lab is due Friday 11:59pm
3. Quiz on sound waves Friday. Review sound wave terms, problem solving, echo problem solving.