WAVES

OBJECTIVE DAY 1

• I will know the three different types of mechanical waves.

• I will know the relationships among speed, wavelength, and frequency.

• I will be able to identify and name the different parts of a wave structure.

• I will be able to solve story problems for the wave equation.

In a wave pool, the waves carry energy across the pool. You can see the effects of a wave's energy when the wave lifts people in the water.

Fun Fact:

A mechanical wave is a disturbance in matter that carries energy from one place to another.

• The material through which a wave travels is called a medium.

Solids, liquids, and gases all can act as mediums.

A vibration is a repeating back-and-forth motion.

The speed of a wave can change if it enters a new medium.

What causes mechanical waves?A mechanical wave is created when a source of energy causes a vibration to travel through a medium.

Three main types of mechanical waves:

-- transverse waves-- longitudinal waves-- surface waves

1. A transverse wave causes the medium to vibrate in a direction perpendicular to the direction in which the wave travels.

Crest

Direction of wave

Trough

Direction of vibration

EXAMPLE OF TRANSVERSE WAVES!

http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html

The wave carries energy from left to right, in a direction perpendicular to the up-and-down motion of the rope.

Transverse Waves

PARTS OF A WAVE• The highest point of the wave is the crest.

• The lowest point of the wave is the trough.

Amplitude

The amplitude of a wave is the maximum displacement of the medium from its rest position.

The more energy a wave has, the greater is its amplitude.

Rest position

High amplitude

Low amplitude

Wavelength can be measured from any point on a wave to the same point on the next cycle of the wave.

Long wavelength Short wavelength

Rest position

2. A longitudinal wave is a wave in which the vibration of the medium is parallel to the direction the wave travels.

Direction of wave Direction of vibration

AN EXAMPLE OF A LONGITUDINAL WAVE

IS A SLINKY

PUSH AT ONE END AND . .

SUMMARY

A surface wave is a wave that travels along a surface separating two media.

Example: Ocean waves

Turn to a partner #1

1. How does a mechanical wave carry energy from one place to another? A. vibration of a medium B. physical transfer of matter C. phase changes of a medium D. interaction of electromagnetic fields

Turn to a partner #1 -- answer

1. How does a mechanical wave carry energy from one place to another? A. vibration of a medium B. physical transfer of matter C. phase changes of a medium D. interaction of electromagnetic fields

Turn to a different partner #2

2. Name the wave in which the vibration of the medium is parallel to the direction the wave travels.A. longitudinal waveB. sound wave C. surface waveD. transverse wave

Turn to a different partner #2

2. Name the wave in which the vibration of the medium is parallel to the direction the wave travels.A. longitudinal waveB. sound wave C. surface waveD. transverse wave

Turn to a partner #3

3. Which example describes a transverse wave?A. sound wave traveling through

airB. ocean wave far from the

shoreC. ocean wave as it approaches

the shoreD. light wave traveling through

space

Turn to a partner #3

3. Which example describes a transverse wave?A. sound wave traveling through

airB. ocean wave far from the

shoreC. ocean wave as it approaches

the shoreD. light wave traveling through

space

SMALL GROUP:Discuss a sport where the

athlete would need to understand the properties

of waves.

ONE EXAMPLE:A surfer needs to understand the properties of waves.