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What is a Wave? •  A Wave is a disturbance that transfers

energy from place to place. In order to pass it’s energy along, waves

can pass through a medium.(-- the material through which a wave travels).

•  (A medium can be a gas, liquid, or solid).

Not all waves pass through a Medium……

•  Some waves DO NOT need a medium, in order to pass its energy along.

•  For example, electromagnetic waves can go through matter such as air, water, and glass.

•  (Other example include: microwaves, •  x-rays used by doctors and dentist, •  and even light)

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Waves transfer energy, not matter. The water in the waves below are carrying energy but are not moving. Waves can only exist as they have energy to carry.

What causes waves? •  Waves are created

when a source of energy causes a medium to vibrate.

•  A vibration is a repeated back and forth or up and down motion.

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How do we classify waves?

•  Waves are classified according to how they move. We classify waves based on the direction in which the particles of the medium vibrate compared to the direction in which the wave moves.

Types of Waves:

• Longitudinal • Transverse • Surface

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Transverse •  Vibrates

perpendicular (at right angles) to the wave travel. These waves move in an “up and down” motion.

(Similar to waving a moving rope)

Parts of a transverse wave: •  The highest point on

a transverse wave is called the “crest”.

•  The lowest point on the transverse wave is called the “trough”.

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Longitudinal Waves •  Vibrates parallel to (in the same direction of)

wave travel. It produces a “back and forth” type of motion. (ex: sound waves) It’s similar to pulling one end of a slinky. The wave

travels through the medium from one end and back again to the other.

Parts of a Longitudinal wave…

•  The parts of longitudinal wavess where the particles are “crowded” is called the compression.

•  The parts of the waves where they are “farthest apart’ is called rarefaction.

“Compression”

ß--Rarefaction-

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Surface Waves •  These are a

combination of longitudinal & transverse waves. They look like transverse waves, but the particles travel through the medium in circles rather than up and down. The particles also

•  Move forward at the crest of each wave and move backwards at the trough.

“Properties of waves”

•  Imagine you are floating on your air mattress in the pool and a friend dives in and creates a huge wave that sends your mattress “a rock-in”!!

•  We can compare the different types of waves similar to the actions that were created by your friend.

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Properties of Waves…..

•  Waves have several properties such as: •  a) Amplitude -------- (the height of the wave) !•  b) Wavelength -------- (the distance between the crest)!•  c) frequency •  d) wave speed

“Amplitude” •  The amplitude of a wave is related to its “height”. A

wave’s amplitude is the maximum distance that the particles of the medium vibrate from their rest point.

•  The rest point is the point where the particles of the medium stay where there is no disturbance.

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“Wavelength” •  This is the distance between two crest. •  The shorter the wavelength the greater the

amount of energy carried. •  The longer the wavelength the lesser amount of

energy carried.

“Frequency” •  --is the number of waves

produced in a given amount of time.

•  The higher the frequency, the greater the amount of energy that was made.

•  The lower the frequency, the lesser amount of energy that was made.

Low frequency

High frequency

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“Frequency” •  Is similar to the

movements of a jump rope. Moving the rope quickly makes a larger number of waves. (in a given time).

•  Moving the rope slowly makes a lower number of waves.

•  Simulation clip on frequency and amplitude of a wave!!!

•  Watch how the

frequency changes along with the amplitude of the waves

Brainpop:

"Waves"

•  How stuff works video clip on waves

•  After the videos, complete the worksheet: “Diagram of a Wave”.

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Practice Time: See if you know the answers:

•  The following questions were taken from last year’s TCAP practice book:

• Questions: 5, 11, 32, 38, and 44

answer: “C”

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Answer: “B”

Answer: “F”

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Answer: “J”

Answer: “G”