Identify the following parts of a wave: 1. A to E 2. B 3. D 4. The line connecting A and G 5. The distance from F to the line.

Identify the following parts of a wave:1. A to E2. B3. D4. The line connecting A and G5. The distance from F to the line

Do Now (6/1/12): Happy Friday!

Exam Review: Please use the rest of class to work on your

review packet. Not working on your packet will result in a

loss of 2 points for today!!! If you have any questions or need any

slides, please ask.

Several positions along the medium are labeled with a letter. Categorize each labeled position along the medium as being a position where either constructive or destructive interference occurs.

Do Now: 4/5

A hiker shouts toward a vertical cliff 589 m away. It takes 3.1 s to reach the cliff. The wavelength is 0.65 m.

1. What is the speed of sound in air?  

2. What is the frequency? 3. What is the period of the wave?

Do Now 4/5

Periodic motion is motion that repeats itself in a regular cycle. List three examples of periodic motion in your life.

Do Now (3/26/12):

Waves3/26/12

Last week before spring break!

Wave: a disturbance that carries energy or matter through space

Pulse: a single disturbance

Periodic wave: a repeated wave

Waves

Mechanical waves: require a material medium to travel (air, water, ropes)

Electromagnetic waves: do not require a medium to travel (light, radio)

Types of Waves:

1.Transverse: medium moves perpendicular to the direction of the wave.

Mechanical Waves

2. Longitudinal: medium moves parallel to the direction of the wave

Mechanical Waves

3. Surface: combination of transverse and longitudinal

Mechanical Waves

Crest: highest point Trough: lowest point Wavelength: shortest distance between

crests and troughs; represented by Greek letter λ (lambda); measured in m or nm

Wave Characteristics

crest

trough

Equilibrium: the position at which the net force is zero

Amplitude: the distance from a crest to where the wave is at equilibrium

Wave Characteristics

Equilibrium position

Period (T ) – time to complete one cycle of periodic motion; measured in seconds (s)

Frequency (f )– # of complete cycles per second; measured in Hertz (Hz)

Wave Characteristics

sHz

Tf

11

1

A radio wave has a frequency of 93.9 MHz (93.9 * 106 Hz). What is its period?

Example:

f = 93.9 * 106 Hzf = 1 / TT = 1 / f

T = 1 / 93.9 x 106 HzT = 1.06 x 10-8 s

Wavelength – super important!!!

f

v

A sound wave has a frequency of 200 Hz and travels the length of a football field(91.4 m) in 0.3s.

a. What is the speed of the wave?

b. What is the wavelength of the wave?

c. What is the period of the wave?

Example:

sms

m

t

dv /6.304

3.0

4.91

msm

f

v52.1

200

/6.304

sf

T 005.0200

11

Use the rest of class to work on the paper: Introduction to Waves. It is due on Wednesday!!!!!

Don’t forget…. Final mouse trap testing is on THURSDAY, MARCH 29!!!

Practice:

Identify the following parts of a wave:1. A to E2. B3. D4. The line connecting A and G5. The distance from F to the line

Do Now (3/27/12):

Use the rest of class to work with the slinkys.

IF YOU TANGLE A SLINKY SO THAT IT NO LONGER WORKS, YOU WILL LOSE POINTS ON YOUR LAB!!!!

REMINDER: Homework is due tomorrow!

Slinky Lab:

Review:

crest

trough

Equilibrium position

sHz

Tf

11

1

A sound wave travels across a football field at 330 m/s. The wavelength is 1.12 m.

1.What is the frequency?

2.What is the period?

Do Now (3/28/12):

From your calculations yesterday, did the size of the pulse have any affect on the speed?

Slinky Lab

Two methods:

THE SPEED OF A WAVE DEPENDS ONLY ON THE MEDIUM!!!

Speed of a wave:

fv t

dv

phenomenon that occurs when two waves meet while traveling along the same medium

Wave interference:

occurs at a location along the medium where two interfering waves have a displacement in the same direction

Constructive interference:

Positive or negative

Constructive Interference

occurs at a location along the medium where two interfering waves have a displacement in the opposite direction

Destructive interference

Equal sized opposite pulses result in a straight line:

What if we have one of each???

Subtract:

What if they are not equal?

They pass through each other:

What happens after they interfere?

When two waves interfere, the resulting displacement of the medium at any location (the AMPLITUDE) is the algebraic sum of the displacements (the AMPLITUDES) of the individual waves at the same location.

The Law of Superposition

Write your name and class period

On the paper on your desk:

Categorize each point as constructive or destructive:

Example:

Classroom textbook p.347 problem 45

4 min!!

Practice (on same sheet of paper):

Take out your mousetrap car and wait quietly for further instructions.

Do Now (3/29/12):

Use the rest of class to work on the paper “Wave Superposition.” It is due on Friday!!!

You can turn this paper in by the end of class for EXTRA credit!!!

If you need to, you may meet with your mousetrap car group.

Practice:

1. Initial proposal – already due 2. Proof of vehicle moving (photo or

video) – already due3. Mousetrap lab (emailed and one

per group) – already due 4. Final mousetrap analysis

questions; (you will get these today) one per group; due tomorrow

5. Mousetrap car results (you will do today)

Components of Project:

1. What is interference?2. What are the two types of

interference?3. What is the difference between

the two types?4. What does the Law of

Superposition state? Happy Day Before Spring Break

Do Now (3/30/12):

Do Now’sSlinky Labs *(if you have not already)

Superposition paper (*if you have not already)

Mousetrap Analysis Questions *(if you have not already)

Please Pass In:

Slinky Lab!!!!!

1.What was your favorite thing you did over spring break?

2.What is one goal you have for the fourth quarter?

Do Now (4/11/12):

1.Slinky Lab Part 2

Please Pass In:

Complete the Unit 2, Worksheet 5. This is your quiz review.

If you finish before the end of class, please turn it in.

If not, you will have to finish for homework.

You will have a quiz on Friday on Wave Properties!

Review:

An incident pulse travels towards a fixed end. What do you think will happen once the pulse reaches the end?

Do Now (4/12/12): (2 min)

A sound wave has a frequency of 200 Hz and travels the length of a football field(91.4 m) in 0.3s.

a. What is the speed of the wave?

b. What is the wavelength of the wave?

c. What is the period of the wave?

Do Now (4/13/12:

sms

m

t

dv /6.304

3.0

4.91

msm

f

v52.1

200

/6.304

sf

T 005.0200

11

Do Now’sHomework – (Waves Unit 2, Worksheet 5)

Wave simulation (if completed)

You have until MONDAY to finish your simulation questions

Pass in:

1. A single disturbance that moves through a medium is_________.

2. The speed of a wave is determined by its_____.

3. The process used to predict the effect of combining two waves as they pass through the same medium is called ____________.

4. Sound waves emanate from a razor at a rate of 50 cycles per second and spread out at 340 m/s. the frequency is___________.

Do Now (4/19/12): Fill in the blank

Complete ONE brainstorm idea for your project and get it initialed by Ms. Timson

Once your brainstorm has been initialed, work on your review sheet.

Reminder: you have a test next Tuesday!!!

Class Agenda:

1. Is a sound wave mechanical or electromagnetic?

2. Is a sound wave transverse or longitudinal?

3. What does a sound wave NOT travel through?

4. What unit is used to measure the loudness of sound?

5. What unit is used to measure the pitch of sound?

Do Now (4/20/12):

Use the rest of class to complete the analysis

Analysis:

Wave Behavior

Clear your desks of everything except your Do Now Sheet and get ready for a POP QUIZ

Do Now:

APRIL FOOLS!!!!!

!!

Boundary: the divide between two different media

Medium: the substance through which a wave travels

Waves at Boundaries

incident pulse: wave approaching the boundary

reflected pulse: the disturbance that returns after bouncing off the boundary

transmitted pulse: the disturbance transmitted to the next medium

Waves at Boundaries

1. What is the difference between constructive and destructive interference?

2. What does the Law of Superposition state?

Real Do Now:

The transmitted pulse (in the more dense medium) is traveling slower than the reflected pulse (in the less dense medium).

The transmitted pulse (in the more dense medium) has a smaller wavelength than the reflected pulse (in the less dense medium).

The speed and the wavelength of the reflected pulse are the same as the speed and the wavelength of the incident pulse.

Less dense to more dense

The transmitted pulse (in the less dense medium) is traveling faster than the reflected pulse (in the more dense medium).

The transmitted pulse (in the less dense medium) has a larger wavelength than the reflected pulse (in the more dense medium).

The speed and the wavelength of the reflected pulse are the same as the speed and the wavelength of the incident pulse.

More dense to less dense

In phase: the same two points on a wave:examples: A&E, B&F, C&G

Out of phase: two points that are not the sameExamples: A&C, E&G

In Phase