12 Weeks to TAKS

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12 Weeks to TAKS Week 5
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• Obj. 5 IPC 5A and 5B Demonstrate wave types and
  their characteristics through a variety of
  activities such as modeling with ropes and coils,
  activating tuning forks and interpreting data on
  seismic waves. Demonstrate wave interactions
  including interference, polarization, reflection,
  refraction, and resonance within various
  materials.
• IPC 6F Investigate and compare series and
  parallel circuits.

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WAVES
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By moving a rope regularly up and down, a
traveling or periodic wave is produced. Waves
transfer energy from one place to by vibrating
something up and down, or back and forth.
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A transverse wave is a wave in which the
particles of the medium are displaced in a
direction perpendicular to the direction of
energy transport.
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. The crest of a wave is the point on the medium
which exhibits the maximum amount of positive or
upwards displacement from the rest position.
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The trough of a wave is the point on the medium
which exhibits the maximum amount of negative or
downwards displacement from the rest position
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The amplitude of a wave refers to the maximum
amount of displacement of a a particle on the
medium from its rest position. The amount of
energy carried by a wave is related to the
amplitude of the wave.
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A longitudinal wave is a wave in which the
particles of the medium are displaced in a
direction parallel to the direction of energy
transport.
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• A compression is a point on a medium through
  which a longitudinal wave is traveling which has
  the maximum density. A region where the coils are
  spread apart, thus maximizing the distance
  between coils, is known as a rarefaction. A
  rarefaction is a point on a medium through which
  a longitudinal wave is traveling which has the
  minimum density.

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A tuning fork serves as a useful illustration of
how a vibrating object can produce sound.
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Characteristics of Waves a. Frequency the
number of complete waves passing a point in space
per second depends on the source b. Wavelength
the distance from a point in a wave to the next
point that wave in the same phase, often
symbolized with l (lambda)
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By knowing the frequency of a wave and its
wavelength, we can find its velocity. Here is the
equation for the velocity of a wavevelocity
wavelength x frequency orv l x f
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• Light waves will always travel in a straight line
  until they hit a barrier. So whether its
  traveling through air, water, glass, diamond, or
  any substance (or none at all), light travels in
  a straight path, until it encounters a different
  medium.

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All visible objects either emit light or reflect
light. When an object either emits light or
reflects it, the light travels in all directions
from the object. If viewed through a pinhole the
light rays encounter no different medium so they
travel in a straight line.
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Wave Properties Reflection

• When a wave hits a barrier, it will be
  reflected depending on the direction of the
  barrier (normal). The angle between the incident
  wave and the normal is the same as the angle
  between the normal and the reflected wave. 

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• Reflections are commonly observed with sound
  waves. Echos are reflected sound waves. When you
  yell in a canyon, the sound wave travels through
  the medium (air in this case), reflects off the
  canyon wall and returns to its origin (you). The
  result is that you hear the echo (the reflected
  sound wave) of your original yell.

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Wave Properties Refraction When a wave
enters a different medium (more shallow region)
at an angle, the direction of waves changes. This
change is called refraction.

• The energy
  transferred depends on the difference between
  the mediums. If there is a significant
  difference, almost all the energy will be
  reflected. If the mediums are similar, most of
  the energy will be transferred.

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• Refraction causes objects to appear in a
  different place than it actually is because when
  light passes into a different medium the light
  path bends.

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Wave Properties InterferenceWhen two waves
traveling in opposite directions through the same
medium collide, the amplitude of the resulting
wave will be the sum of the two initial waves.
This is called interference and there are of two
types
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• 1. Constructive interference is when the
  amplitudes of the initial waves are in the same
  direction. The resulting wave will be larger than
  the original waves.

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• 2. Destructive interference is when the
  amplitudes of the initial waves are opposite. The
  amplitude of the resulting wave will be zero.

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Wave Properties Polarizaton

• A light wave which is vibrating in more than one
  plane is referred to as unpolarized light.
  Polarized light waves are light waves in which
  the vibrations occur in a single plane. The
  process of transforming unpolarized light into
  polarized light is known as polarization.

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Wave Properties Resonance

• Resonance causes an object to move back and forth
  or up and down.

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• For resonance to occur three things must be
  present.
• A) An Object With a Natural Frequency.
• B) A Second Object that Can Oscillate at the Same
  Frequency as the Natural Frequency Energy is
  transferred by a wave from a vibrating object to
  a second object.
• C) A Lack of Energy Loss For an object to
  resonate energy has to build up in the object.

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Electricity
Electricity generally refers to the flow of
electrons.
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Types of Electricity

• Static Electricity - no motion of free charges
• Current Electricity - motion of free charges
• Direct Current (DC)
• Alternating Current (AC)

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Electrical CircuitsA circuit is a loop of wire
with its ends connected to an energy source such
as a battery. One end of the wire is connected to
the positive terminal the other end of the wire
is connected to the negative terminal. The wire
is connected in this way so a current can flow
through it.
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Resistors can be connected in series that is,
the current flows through them one after another.
Series Circuits
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Parallel Circuits
A parallel circuit is rather like two or more
series circuits connected to the same energy
source. For example, here is a parallel circuit
connecting a battery and three resistors.
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• Series circuits have two disadvantages when
  compared with parallel circuits. The first
  disadvantage is that, if one component in a
  series circuit fails, then all the components in
  the circuit fail because the circuit has been
  broken. The second disadvantage is that the more
  components there are in a series circuit, the
  greater the circuit's resistance.

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• Parallel circuits have two advantages when
• compared with series circuits.
• The first advantage of a parallel circuit is that
  a failure of one component does not lead to the
  failure of the other components. This is because
  a parallel circuit consists of more than one loop
  and has to fail in more than one place before the
  other components fail.
• The second advantage of parallel circuits is that
  more components may be added in parallel without
  the need for more voltage.

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Ohms Law

• Ohm's Law deals with the relationship between
  voltage and current in an ideal conductor.
• Ohm's Law is given by
• V I R

R
V
I
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Voltage

• Voltage (V) can be thought of as the force
  pushing electric charges along a conductor

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Resistance

• Resistance (R) is a measure of how difficult it
  is to push the charges along.

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Current

• Electric current (I) is the movement of electric
  charge in a conductor.