TCAP Practice Questions•Complete question #1-4

•Please do NOT write in TCAP booklet!

•Bubble in the correct answer on the bubble sheet provided.

•Scan your bubble sheet and record your score.

•We will discuss the questions after everyone has scanned.

•You have 5 minutes to answer the questions.

•Your time starts as soon as the bell rings.

BELLWORK 4/7/14

THINK OF A TIME YOU HAVE EXPERIENCED WAVES…

70. Waves

Objectives

• SPI 0707.11.5 Compare and contrast the different parts of a wave.

• SPI 0707.11.6 Differentiate between transverse and longitudinal waves in terms of how the are produced and transmitted.

NATURE OF WAVES:A wave is a disturbance that

transmits energy through empty space or through a medium.

Look @ pg. 602!

The “Medium” of a Wave…• A medium is the substance or material the

wave travels through–Can be a SOLID, LIQUID, or GAS–Example:

• Seismic waves (earthquakes) travel through the ground

• Ocean waves travel through water• Light waves travel through space from the sun

Question:You are a commander of a space station located about halfway between Earth and the moon. You are in the Command Center, and your chief of security tells you that sensors have just detected an explosion 61.054 km from the station.How long will it be before you hear the sound of the explosion?

Sound waves need a medium through which to travel. If there are no particles to vibrate, no sound is possible!Electromagnetic waves, like visible light, can transfer energy without going through a medium.

Longitudinal vs. Transverse Waves

Transverse Waves

• Examples: light waves, water waves electromagnetic waves

Electromagnetic Waves

ROY G. BIV was a colorful guy.

Parts of Transverse Waves

• Crest – highest point (above)

• Trough – lowest point (below)

Transverse Particle Motion• Particles or energy moves

perpendicular to wave motion

Draw a transverse wave. Label the wave motion, particle motion, crest, & trough.

Check for Understanding…

Longitudinal Waves

• Examples: sound waves

Parts of Longitudinal Waves:

• Compression: place where particles are closest together

• Rarefaction: place where particles are furthest apart

Longitudinal Particle Motion

• Particles or energy moves parallel to wave motion

Draw a longitudinal wave. Label the wave motion, particle motion, compression, & rarefaction.

Check for Understanding…

A wave is transporting energy from left to right. The particles of the medium are moving back and forth in a leftward and rightward direction. This type of wave is known as a ____.a. mechanicalb. electromagneticc. transversed. longitudinal

Check out this longitudinal wave…

http://utahscience.oremjr.alpine.k12.ut.us/sciber08/8th/forces/movies/compress.mov

Properties of Waves• Amplitude – height of the wave above or

below rest• Larger amplitude = more energy• Label the amplitude on the transverse wave.

Describe the amplitude…

•Wavelength= distance between any two corresponding locations.

Usually measured in one of three ways:

1. crest to next crest

2. trough to next trough

3. from the start of a wave cycle to the next starting point

Label the wavelength on both types of waves.

Check for Understanding…

As a wavelength decreases, the crests of the wave

A become wider.

B become shorter.

C get closer together.

D get farther apart.

Frequency:The number of waves in given

amount of time higher frequency = more energy

Units: Hz = Hertz

Frequency:Measure the frequency by counting

either the number of crests or troughs that pass a point in a

certain amount of time.

Count the frequency for each wave.High or Low Frequency?

Properties of Waves

Wave speed is the speed at which a wave travels.

Wave speed can be calculated by using the following formula:

v = λ x f or v = λ • f

v = wave speed

λ = wavelength

f = frequencyDetermine the wave speed of a wave that has a wavelength of 5 m and a frequency of 4 Hz.

Express the units as m/s.

Longitudinal vs. Transverse Waves

Let’s make waves…

Wave Displacement (motion of the particles)

Surface Waves

Check for Understanding

How does the pencil look How does the pencil look broken?broken?

Wave Interactions

The frequencies at which standing waves are made are called resonant frequencies.

When an object vibrating at or near the resonant frequency of a second object causes the second object to vibrate, resonance occurs.

A resonating object absorbs energy from the vibrating object and vibrates, too.

Tacoma Narrows Bridge AKA “Galloping Gertie” is a phenomenon, or an extraordinary event, that caused a lot of destruction because of resonance.

Watch this Video!

71. Waves Lab

Create a transverse and longitudinal wave using paper

confetti.