5a and 5b: waves. and wave – a wiggle in space and time for example: light and sound *a wave...
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5A and 5B: Waves
Wave – a wiggle in space andand timeFor example: light and sound*A wave exists over space and time**
Transverse WaveMidpoint (Equilibrium)
Parts of a Transfers Wave
Crest (high point)
Trough (low point)
Amplitude - distance from midpoint to crest or trough
Wavelength () – distance from one crest (trough) to the next
Frequency (f)how frequently a vibration occurs
(# of crests per second)vibrations per second
Heinrich HertzThe unit of frequency is
the Hertz.
1 vibration per second = 1 Hertz
Frequency/wavelength relationship
• If frequency and pitch go then wavelength goes
• If frequency and pitch go then wavelength goes
25.3 Wave MotionSound and light waves
move.As waves move, matter is NOT passed along them. Movement of energy, not
material
For example:When you create a
wave with a rope, it is the disturbance that
moves along the rope, not the rope itself.
25.6 Longitudinal Wave
The energy compresses and expands along a straight
path.
Place a slinky on the ground and try to push and pull it.
Sound waves are longitudinal or compression waves.
25.7 Interference
Interference pattern: patterns formed when waves overlap
2 types of interference:1.constructive (adding)–
reinforcing interference when waves align at the crests and troughs**individual effects are
increased**
Constructive Interference- the result would be a larger wave
2.Destructive (subtracting)– cancellation interferencewhen the crest of one wave aligns with the trough of another**their individual effects are reduced**
Destructive Interference- the result would be a flat line
Sound Waves • Sound travels MUCH slower
than lightEX: lightening and thunder
• The speed of sound at room temperature is
340 m/s340 m/s
Natural frequency – amount of vibration in a certain time (frequency) that an object naturally tends to vibrate
•Resonance – a phenomenon that occurs when an object reaches its natural frequency (from another source)
EX: marching over bridges, opera singer breaking a glass by singing
Light waves are transverse waves.
Polarization – the filtering out of all vibrations in a certain direction- only letting waves in a certain direction get through
Reflection – bouncing off(flat surface parallel to H2O)
Refraction – penetrating (goes through)(flat surface perpendicular to H2O)
• Reflection – bouncing offex: mirrors, echos
• Refraction – penetrating (goes through), changes the way things look as they travel through materials of different densities.
Ex: straw in water, heat waves along a highway