Aim: What are waves?

Do Now: Make a list of at least 5 different

types of waves.

Homework: Study for quiz.

1. What is a wave? • A disturbance that travels through matter or empty space, & transfers energy

• Ex. a ripple in a pond, or light from the sun

2. What is a medium?

• The matter through which a wave moves

Ex. Solid, liquid, or gas

a) Water is a medium for ocean waves

b) Air is a medium for sound waves

3. What type of waves require a medium?

4. What types of waves don’t require a medium?

Mechanical Waves

Electromagnetic Waves

• Can travel through a vacuum (empty space) or a medium

Ex) Light or X-Rays

5. What are 2 types of waves?

1. Transverse

&

2. Longitudinal (a.k.a. Compressional)

6. How does a transverse wave move?

The motion of the medium is at right angles to the direction of the wave

Ex. A ripple in water, light, electromagnetic wavesMedium

    

Energy of the Wave

7. How does a longitudinal wave move?

The motion of the medium is parallel to the direction of the wave, or back & forth

Ex. Sound

Transverse Waves Longitudinal Waves

1. Motion of the medium is at right angles to the direction of the wave

2. Ex) Electromagnetic waves

3. Don’t require a medium

1. Motion of the medium is parallel to the direction of the wave

2. Ex) Sound

3. Require a medium

Compression Rarefaction

The space in the medium where the particles are crowded together

The space in the medium where there are fewer particles

Aim: What are characteristics of waves?

Do Now: Take out a piece of loose-leaf, put your name on top & # it 1-5. Prepare for quiz.

Homework: Study for Quiz & Complete questions 2 & 3 in note-packet on a separate piece of loose-leaf

***Make sure to write out the formulas, plug in #s, & give correct answer & units

1. Waves only transfer _______________.

2. What type of waves require a medium?

3. The motion of the medium is at right angles to the direction of the wave describes a _________ type of wave.

4. Another name for a compressional wave is a ___________ wave.

5. In a Compressional wave, the space in the medium where there are fewer particles is called a _________________.

Name_____________ What are waves? - Quiz

1. What are the parts of a wave?

a) Crest -

b) Trough -

c) Normal

Resting Position -

the highest point of a Transverse Wave

the lowest point of a Transverse Wave

position of the medium without a wave disturbance

2. What are 3 characteristics that all waves have?

1. (D) Amplitude,

2. (E) Wavelength, &

3. Frequency

3. What is Amplitude?

• the maximum movement from the rest position

energy = amplitude

4. What is Wavelength?

• the distance between 2 consecutive crests or troughs

• Measured in meters or cm

• The symbol = λ (lambda)

5. What is frequency?

a) The number of waves that pass a point in one second

b) Importance:• Distinguishes one color of

light from another

• Higher frequency = higher sound (pitch)

c) Measured in units called Hertz

1 Hz = 1 wave/sec.

Example:

You are at a lighthouse on the tip of an island. You notice that 1 wave passes every 2 seconds.

What is the frequency of the wave?

1 wave/2 sec.

Or

= 0.5 Hz

6. What is the relationship between frequency & wavelength?

• As Wavelength decreases, Frequency increases.

• As wavelength increases, Frequency decreases.

• Inverse Relationship

Summary:

1. How do you measure wavelength?

2. Which wave has the greatest wavelength?

3. What is frequency?

4. Which wave has the greatest frequency?

5. What are the frequencies for waves A, B, C?

1. How can you calculate the speed of a wave?

Recall:

How is speed calculated?

Wave Speed =

Wavelength X Frequency

or

V = L*F

meters X (waves)

(sec)

Example 1:

Waves pass the end of a dock 2 times every second. If the waves are 3 meters long, how fast are they moving?

V

L F

V = L * F

V = 3.0 m * 2.0 Hz

V = 6 m/s

Example 2:

A wave has a frequency of 10 Hz & a wavelength of 30 m.

What is its speed?

V = L * F

V = 30m * 10 Hz

V = 300 m/s

Example 3:

The speed of a wave is 200 m/s, & the frequency is 20 Hz.

What is its wavelength?

L = V

F

L = 200 m/s

20 Hz

L = 10 meters

• Yahoo! Video Detail for f14transonic.mpg

• Wave Parts

• http://www.acs.psu.edu/users/sparrow/movies/newbackwardcomp.flat.mov

Aim: What does the speed of a wave depend upon?

Do Now: Take out homework & prepare for quiz.

Homework: Study for Quiz.

Quiz – Characteristics of Waves1. Write the letter that identifies: Amplitude2. Write the letter that identifies: Wavelength3. The number of waves that pass a given point in each second is known as ____________.

4. The loudness of a sound is determined by its______________.

(Wavelength, Frequency, or Amplitude)

5. You are at a lighthouse on the tip of an island. You notice that 15 wave passes every 3 seconds.

You are at a lighthouse on the tip of an island. You notice that 15 waves passes every 3 seconds.

What is the frequency of the wave?

1. What does the speed of a wave depend upon?

The medium through which it travels.

Recall:

What is a medium?

2. What are some properties of a medium which can affect the speed of sound?

1. Density,

2. Elasticity, &

3. Temperature

3. How does density affect the speed of a wave?

(Is it easier to stir a spoon through water or molasses? Why?)

• Waves move slower in a denser medium

Due to:• More mass in a

given volume &

• More inertia to overcomeRecall – What is inertia?

4. How does elasticity affect wave speed?

(Is it easier to run on the beach, or on a track?)

Elasticity = the ability of a medium to return to its original (resting) position

• Waves move faster in more elastic mediums

5. What phase of matter is the most elastic?

• Solids are more elastic than liquids &

• Liquids are more elastic than gases

6. How does temperature affect the speed of sound?

Lower temperature = slower speed of

sound

Higher temperature

= faster speed of sound

• Direct Relationship

Summary:

In what medium does sound travel the fastest?

The slowest?

Aim: What are 4 types of wave interactions?

Do Now: Prepare for Quiz.

Homework: Study for Quiz & Read pages 327 – 329 & 339, Answer Ques. #1 on pg 343

1. What is A2. B3. C4. D5. G

6. What type of wave is this?

7. The number of waves that pass a point in one second is known as __________.

8. What types of waves require a medium?

9. As temperature increases, the speed of a wave __________.

10. What do waves transfer?

Bonus:

What is the relationship between wavelength & frequency?

1. What do you know about waves traveling in the same medium?

1. They move at a constant speed &

2. They move in a constant (same) direction

2. What happens when a wave hits an obstacle, a different medium, or another wave?

1. Reflection

2. Diffraction

3. Refraction (with or without dispersion)

4. Interference

3. What causes a Reflection?

a) The bouncing back of a wave when it hits a barrier

b) Surfaces reflect light waves at the same angle at which they are hit.

c) Examples:

Looking in a mirror, or an echo

Reflection

4. What is the Law of Reflection?

angle of incidence = angle of reflection

orAngle I = Angle R

Example:If the angle of incidence = 30° the angle of reflection = _______

5. What is Diffraction?

The bending of waves around an obstacle

Draw This Picture

6. What is Refraction?

The change in direction and speed of waves when they move from one medium to another

Refraction in Glass Lenses

7. What happens when light hits a glass prism?

1. Refraction

&

2. Dispersion -the process of separating white light into a spectrum of color

Ex. A prism forms a rainbow

8. What 3 processes occur as a light wave hits a boundary between 2 different mediums?

1. Reflection

2. Absorption

3. Refraction

9. Why do we perceive certain objects as being the color red?

• When white light hits a red object the red light is reflected & taken in by our eye.

• All other colors are absorbed.

10. What is true about a white object?

11. What is true about a black object?

It reflects all colors of the spectrum, as well as heat.

 

It absorbs all colors of the spectrum, as well as heat.

What happens during Interference?

Destructive Interference

2 or more waves arrive at the same place at the same time

Constructive Interference

Tacoma Narrows Bridge

• http://www.tau.ac.il/~simcha/Tacoma-a.mov

Aim: What are properties of sound?

Do Now: Prepare for quiz

Homework: Study for tomorrow’s quiz & Friday’s Exam on waves.

For Questions (1-5, 7 & 10) Choose the Answers: Reflection, Refraction Diffraction or Disbursion)

1. The change in direction and speed of waves when they move from one medium to another is called _________________.

2. An echo is an example of _________.

3. The bending of a wave around an obstacle is called ___________.

Quiz - Wave Interactions

4. This picture shows:

5. The bouncing back of a wave when it hits a barrier is called ______________.

6. _____________ absorbs all colors of the spectrum, as well as heat. (Black or White)

7. This picture

demonstrates_______

8. If the total angle =

80 degrees, what is

the angle of reflection?

9. When white light hits a red object the red light is ______________. (Absorbed or Reflected)

10. When white light hits a prism refraction & ____________ occurs.

1. What is sound? 1. Is a form of energy,

2. Has longitudinal waves produced by vibrations, &

3. Can’t travel in empty space (vacuum)

It Needs a Medium!

2. What factors affect the speed of sound?

1. Medium2. Elasticity3. Temperature

Waves move faster: a) in solids, b) more elastic, c) & higher temperatures

3. What are properties of sound?

1. Frequency & Pitch

2. Intensity & Loudness

4. What is pitch? a) Pitch is a description of a sound as high or low.

b) This depends on how fast the particles of a medium vibrate, or the frequency of the waves.

c) frequency = pitch (higher sound)

frequency = pitch (lower sound)

5. What are humans capable of hearing?

• Human ear can detect 20 to 20,000 Hz (vibrations/sec)

20,000 Hz = ultrasonic

20 Hz = infrasonic

6. What is the doppler effect?

    The change in pitch due to or frequencies, which result from sound waves being pushed together, or spread apart.

    This occurs whenever there is motion between the source of a sound & its receiver.

http://www.colorado.edu/physics/2000/applets/doppler.html

http://www.colorado.edu/physics/2000/applets/doppler2.html

7. What is intensity?

1. The amount of energy carried by a wave in a certain amount of time.

2. This determines the loudness of a sound.

3. The decibel (dB) scale measures intensity.

Sonic Boom

sonic_boom.mpg - Yahoo! Video

Aim: What types of waves make up the electromagnetic spectrum?

Do Now: Prepare for quiz

Homework: Study for tomorrow’s quiz & this Friday’s

Exam on Waves.

1. Above 20,000 Hz is known as ___________.

2. The number of waves/sec is known as _______.

3. As frequency increases, pitch __________.

4. Intensity causes an increase in amplitude of a wave which will cause an increase in ________.

5. Sound is an example of a __________ wave.

Bonus: Where is the pitch higher? (Point A or B)

Name_____________ Sound – Quiz #1

A B

1. Sound is an example of a __________ wave.

2. Below 20 Hz is known as ___________.

(Ultrasonic or Infrasonic)

1. The number of waves/sec is known as _______.

2. As frequency decreases, pitch __________.

3. Where is the pitch lower? (Point A or B)

Bonus: Intensity causes an increase in amplitude of a wave which will cause an increase in ____________.

Name_____________ Sound – Quiz #2

A B

1. What are electromagnetic waves?

a) Waves consisting of electric & magnetic fields

b) positioned at right angles to each other & to the direction of the wave motion

c) Carry energy

d) Travel in a vacuum or medium

What type of wave is an electromagnetic wave?

2. How are electromagnetic waves arranged?

• In order of wavelength & frequency

• in what is known as the Electromagnetic

SpectrumRecall:

What do you know about relationship between wavelength & frequency?

What do you notice about frequency, energy & wavelength?

What do you think about the sizes of the various waves?

3. What are the 6 groups of electromagnetic waves?

Radio Waves

Infrared Visible

(White)

Light

Ultra-Violet

X-Rays

Gamma

Rays

Least Energy

& Frequency

Longest Wavelength

Highest

Energy

&

Frequency

Shortest Wavelength

Increasing Frequency & Energy

Decreasing Wavelength

4. What is the relationship between frequency , energy, & wavelength?

a) As frequency increases, energy increases

= Direct relationship

b) As frequency increases, wavelength decreases

= Inverse relationship

6. What are characteristics of each type of wave?

Radio Waves Infrared Visible

Light

Ultra-Violet

X-Rays

Gamma

Rays

6. What are characteristics of each type of wave?

Radio Waves Infrared Visible

Light

Ultra-Violet

X-Rays

Gamma

Rays

Transmit radio (AM or FM) & TV waves

Micro-waves (high frequency Radio waves)

Radar

6. What are characteristics of each type of wave?

Radio Waves

Infrared Visible

(White)

Light

Ultra-Violet

X-Rays

Gamma

Rays

Felt as heat

Can be used to make a picture called a

Thermogram

How are thermograms made?

6. What are characteristics of each type of wave?

Radio Waves

Infrared Visible

(White)

Light

Ultra-Violet

X-Rays

Gamma

Rays

The only waves that can be seen!

ROY G BIV

Needed for photo-synthesis

6a) Which color has the greatest wavelength?

6b) Which color has the greatest frequency & energy?

Red

(Least frequency & energy)

Violet

(it has the shortest wavelength)

6c) What else do we know about visible light?

a) It can act as a wave or a tiny bundle of light energy called a photon

b) Nothing in the universe travels faster

(300 million m/s in a vacuum)

6d) Do you see lightening first or hear it first?

Why?

Lightening is always seen first because:

light travels much faster than sound

Aim: What types of waves make up the electromagnetic spectrum? (continued...)

Do Now: Prepare for quiz

Homework: Study for tomorrow’s quiz & this Friday’s

Exam on Waves.

Electromagnetism – Quiz #1

1. Which wave has the greatest frequency?2. Which wave has the greatest energy?3. Which wave has the longest wavelength?4. Visible light can act as a wave or a tiny

bundle of light energy called a _________.5. What type of wave can be felt as heat?

Electromagnetic Waves – Quiz #2

1. Which wave has the lowest frequency?2. Which wave has the lowest energy?3. Which wave has the shortest wavelength?4. What type of wave can be felt as heat?5. Visible light can act as a wave or a tiny

bundle of light energy called a _________.

6. What are characteristics of each type of wave?

Radio Waves

Infrared Visible

Light

Ultra-Violet

X-Rays

Gamma

Rays

Can kill cells

Cause

or

Cause skin to make Vitamin D

sunburnstanning

6. What are characteristics of each type of wave?

Radio Waves

Infrared Visible

Light

Ultra-Violet

X-Rays Gamma

Rays

Used to make an image of bones

Can cause cell defects (mutations)/cancer

What does the dentist do to you before he/she takes an X-Ray of your teeth?

Why?

6. What are characteristics of each type of wave?

Radio Waves

Infrared Visible

Light

Ultra-Violet

X-Rays

Gamma

Rays

Certain radioactive materials & nuclear reactions create these

Can be used in medicine

7. What do U/V rays, X-rays, & gamma waves have in common?

a) They have such high energies & great penetrating abilities

b) Can cause cell mutations, cancer, & lead to death

Summary

Aim: Review: What do you know about waves?

Do Now: Prepare for quiz.

Homework: Bring in a pencil & calculator &

Study for tomorrow’s Exam on Waves!!!

Electromagnetic Waves 2 – Quiz #1

1. What type of wave is used to see bones?2. What type of wave is used by humans to make

Vitamin D? 3. Compared to X-Rays, which wave has a higher

frequency?4. What type of wave can give you a tan or

sunburn?5. What type of wave is given off from some

radioactive materials?

Electromagnetic 2 – Quiz #2

1. What type of wave is used by humans to makeVitamin D?

2. Compared to X-Rays, which wave has a higherfrequency?

3. What type of wave can give you a tan or sunburn?

4. What type of wave is given off from nuclear reactions?

5. What type of wave is used to see bones?

Aim: Exam – What do you know about Waves?

Do Now: 1. Take out pencil & calculator.

2. Put up your binder.

3. Uncover your textbook & keep it out on your

desk.

Homework: Big 8 Review Book pgs

Radio Waves

Infrared Visible

(White)

Light

Ultra-Violet

X-Rays

Gamma

Rays

Least ________

& ________

Longest _________

Highest

_________

&

_________

Shortest _________

____________________________

____________________________

ROY G BIV