For grade 7 lesson in 3rd quarter

1. WAVE
INTERFERENCE
Physics
4

2. ● a phenomenon that occurs
when two waves meet while
traveling along the same
medium.
Wave Interference
● occurs when disturbances
are near one another and
their series of waves
overlap.

3. Types of Interference
-- a type of interference
that occurs at any location
along the medium where the
two interfering waves have
a displacement in the same
direction.
-- a type of interference that
occurs at any location
along the medium where
the two interfering waves
has a displacement in the
opposite direction.
Constructive
Interference
Destructive
Interference

4. Constructive Interference Destructive Interference

5. ● When two waves interfere,
the resulting displacement
of the medium at any
location is the algebraic
sum of the displacements
of the individual waves at
that same location.
The Principle of
Superposition
Put Another
Way…
The resultant
wave is the
result of adding
the two
interfering
waves.

6. Methods of
Determining
Resultant
1. Pick strategic points.
2. Use grid to identify the Y of
wave 1 and wave 2 at each
point.
3. Add the Y of the two waves
to determine the y of the
resultant. Place a dot on the
grid at that point.
4. Once you have enough
points, draw the resultant
wave.

7. Applying Superposition
Principle
(Constructive Interference)
Applying Superposition
Principle
(Destructive Interference)

8. -- Standing wave patterns
are produce as the result
of the repeated
interference of two waves
of identical frequency
while moving in opposite
directions along the same
medium.
Standing Waves Standing waves are
waves that appear to
be standing still and
vibrating.

9. Nodes and Antinodes
-- The nodes are the points in
the waves without displacement.
It is always located in the same
location along the medium,
giving the appearance of
standing still.
-- The antinodes are the location
of maximum amplitude in waves.
-- points along the medium which
oscillates back and forth
between a large positive and
negative displacement.

10. SUMMARY
 Wave interference is the interaction of waves with other waves.
 Constructive interference occurs when a crest overlap with the
crest of other wave.
 Destructive interference occurs when trough overlap with the
crest of other wave.
 The superposition principle states that when two or more
waves interact in space, the resultant disturbance is equal to
the algebraic sum of individual disturbances.
 Standing waves are formed when there repeated interference
of two waves of identical frequency while moving in opposite
directions along the same medium.