Chapter 5, Section 2

Making Waves

January 5, 2011HW: PTG #1, 2, 5-8, pg. 505-506, Due Monday, Bring

Tissues

• Learning Objective:– Describe how waves carry

energy– Describe how wavelength,

frequency and speed of a wave are related

• Success Criteria:– Observe the motion of a pulse– Calculate the speed of a wave

pulse– Observe standing waves– Investigate the relationship

among wave speed, wavelength, and frequency

– Make a model of wave motion– Distinguish between transverse

and longitudinal waves

• Do Now:– 5.1 Quiz– Write LO and SC

on a new left-side page

– WDYS/WDYT pg. 492

Investigate: Part A

• Stadium Wave• Standing Wave • #1-Answer a-d in your notebook

January 6, 2011HW: PTG #1, 2, 5-8, pg. 505-506, Due Monday, Bring

Tissues

• Learning Objective:– Describe how waves carry

energy– Describe how wavelength,

frequency and speed of a wave are related

• Success Criteria:– Observe the motion of a pulse– Calculate the speed of a wave

pulse– Observe standing waves– Investigate the relationship

among wave speed, wavelength, and frequency

– Make a model of wave motion– Distinguish between transverse

and longitudinal waves

• Do Now:– Brain Dump: List

everything you know about waves

Part A Big Idea?

• Wave moves, but people stay stationary

• Waves are produced by adjacent particles move up and down, causing the wave to move across.

Investigate: Part B

• Transverse Waves• Demo #1-5• You are writing in your notebook• #6-7-in groups• #7-choose amplitude as a class– Prediction: How do you think amplitude

will affect the speed of the wave?– Groups 1-2, 3-4, 5-6 different amplitudes

• #10-13 Demo then in groups• #14-Demo, discuss energy• #15-groups, discuss

Part B Big Ideas

• Speed of a wave=distance/time

• Frequency=#times the wave moves up and down each second

• Energy travels in waves

• Transverse Wave:

• Standing Wave:

Investigate: Part C

• Longitudinal Waves• Complete all sections, OK with

teacher

Part C Big Ideas

• Compressional/Longitudinal Waves

Investigate: Part D

• Skip

Vocabulary ActivityBook Definition: Definition in YOUR words

Example Picture or Equation

Physics Talk

• Waves Transfer Energy

• Example

• A wave transfers energy with no transfer of mass

• When you throw a ball the mass and kinetic energy move from one place to another

• A wave transfers only energy, no mass is moving.

Physics Talk

• How is energy transferred?

• Chemical energy in musclesmechanical energy in armspring

• Energy transferred from one form to another, but TOTAL energy remains the same…Conservation of Energy!

Physics Talk

• How do waves “add”?

• They continue to travel as though the other wave never existed.

• http://www.youtube.com/watch?v=Xqo6sEt1cUE

Physics Talk

• Periodic Wave

• Crest

• Trough

• Amplitude

• Repetitive series of pulses

• Highest point on a periodic wave

• Lowest point on a periodic wave

• Height of crest or depth of trough

Physics Talk

• How does amplitude relate to sound?

• How does amplitude relate to energy?

• Large amplitudeLoud sound!

• Small amplitudesoft sound

• Large amplitudeLarge amount of energy

• Small amplitudesmall amount of energy

• Wavelength (λ)

• Frequency (f)

• Distance between two consecutive crests or troughs

• Symbol is λ (pronounce lambda)

• Number of waves per unit time

• Usually waves/sec called hertz (Hz)

Physics Talk

• Period (T) • Time required to complete one complete wave (crest-trough-crest)

• Period and frequency are inversely proportionate

• P=1/f• f=1/T

Physics Talk

• Transverse Waves

• Compressional (Longitudinal) Wave

• The medium moves perpendicular to the direction of the wave

• The medium moves parallel to the direction of the wave

• http://www.youtube.com/watch?v=MoVz2ENJb8M

Physics Talk

• Standing Wave • Wave pattern that remains in a constant position.

• Does not go right/left, but does go up/down.

• http://www.youtube.com/watch?v=03cUrkjqdE0

• Node

• Antinode

• Place on a standing wave that is motionless

• Point on a standing wave where the displacement (movement) is greatest

• What type of wave is sound?

• Compression Wave• Air molecules get

compressed and move through the air

• How can you calculate the speed of a wave?

• Speed=Distance/Time

• Wave speed=wave frequency x wavelengthv=fλ

Sample problems on pg. 502

Essential Questions

• Pg. 504–What does it mean?– How do you know?–Why should you care?

HW: PTG #1, 2, 5-8, pg. 505-506