Properties of A Wave

Properties of A Wave

• Wave – transfer of energy from one point to another without the transfer of matter between the two points. .

Electromagnetic Waves

Electromagnetic waves

• Electromagnetic waves-can travel through the vacuum of space.

Mechanical Waves

• Mechanical waves - disturbance in matter that carry energy from one place to another.

• -Requires a medium through which to travel

• The Medium can be solid, liquid or gas.

• Drop Pebble in water- creates concentric circles that waves moves away from the pulse.

Surface Waves

Surface waves

• The seagull floating in the water (or water molecule) moves in a roughly circular path as the wave travels past.

Surface Waves in Earthquakes

Mechanical waves ( 2 types)

• Categorize the way by the way the particles move.

• What kind of wave is this ?

• Longitudinal or Transverse?

• -Wave travels horizontally

• oscillates vertically, particles move at right angles to the motion of the wave

Mechanical Waves

• Longitudinal -the medium vibrate parallel to the direction of the wave

Waves Properties and Behavior

• Waves repeat over a distance equal to the wavelength.

• wavelength Lambda (λ)

• (λ) is the distance between two consecutive crests or troughs

• Crest of the wave- highest points

• Troughs of the wave – lowest point

• Distance from on crest to the next crest or trough to the next trough is a repeated length that equals the ( Wavelength)

• λ = wavelength • Disturbance over which

wave repeats.

• SI Unit = meter (m)

Connecting Ideas

• Learned about Period, Amplitude.

• Wavelength is the distance crest to crest.

• Period is how long it took to complete the cycle ( form crest to crest).

Characteristics of the wave

• T ( period) of a wave is the time required for one ( wavelength to pass a given potion.

• Frequency f = 1/ T• Frequency is the inverse

of T

• Amplitude (A) is the greatest displacement from the equilibrium

• A from equilibrium to crest same as A from equilibrium to the trough

• In a longitudinal wave • The crest = high

pressure= compression

• The trough = low pressure = rarefaction

• How do you find the velocity of a wave?

• If λis the distance• And T is the time

What is the Velocity of the wave?

• V = d/t

• Speed = wavelength/ Period

• V = λ / T

• V = λ f

• What is the SI units for the velocity of a wave?

• SI units for velocity is always m/s

• What determines the speed of the wave?

• f , T , λ

• V (speed) = determined by the properties of the material medium, through which it travels

• Generally – waves travel faster in mediums that are hard or stiff

• Travel slower in mediums that are soft or squishy.

• Example• Sound in air 343 m/s • Sound in water 1,400 m/s ( not as compressible)• Sound in solid – Steel- 5,960 m/s

• Sound travels faster in warmer air

• WHY?

• Ocean waves – speed greater in deep water then shallow water (produce surf

• Speed of light in vacuum, commonly denoted c, is a universal physical constant (299792458 meters per second)

• C = 3.00 x 108 m/s

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