How does the distance between two slits affect the interference pattern of water waves?
- Background information
Energy is a fundamental concept in physics and is often described as the capacity to do
work or cause change. It exists in various forms, all of which allow for movement, growth, heat,
light, and other effects to occur in the universe. There are different forms of energy. Kinetic
Energy is the energy of motion, for example a rolling ball, flowing water, and wind. Potential
Energy is stored energy based on an object’s position or condition, for instance a stretched
rubber band which has elastic potential energy or a pencil on the edge of the table which has
gravitational potential energy. Thermal Energy is related to the temperature of an object,
resulting from the movement of particles within matter. The faster the particles move, the
higher the thermal energy is in an object. Chemical Energy is stored in the bonds of atoms and
molecules, and when chemical reactions occur, the energy is released. Chemical energy is stored
in food, batteries, fuel, and other objects. Electrical Energy is the movement of electric charges,
commonly used to power devices and transferred in electric currents. Nuclear Energy is stored
in the nucleus of atoms and released through nuclear reactions, such as fission or fusion. Light
Energy is electromagnetic energy that travels in waves, such as X-rays, visible light, and radio
waves. This form of energy does not require a medium and can travel through a vacuum, like
sunlight through space. In 1842, a German surgeon called Julius Robert von Mayer first stated a
principle known as the conservation of energy which states that energy can’t be created or
destroyed, it only changes from one form to another.
Waves are disturbances in a medium that transfer energy from one place to another
without the movement of matter. They occur when energy is applied to a medium, causing
particles to oscillate, vibrate, or fluctuate around a central point. Waves can travel through
different mediums, such as air, water, or solid objects, and they can also move through a
vacuum, as is the case with electromagnetic waves. There are 2 main types of waves. The first
type of wave is mechanical waves which require a medium for it to travel through. This type of
wave can be further categorised into Transverse Waves and Longitudinal waves. In transversal
waves, the particles move perpendicular to the wave's propagation. An example is a water wave,
where the water moves up and down as the wave moves forward. In longitudinal waves, the
particles move in the same direction as the propagation of the wave. Sound waves are a common
example, where compressions and rarefactions travel through the air. The second main type of
waves are electromagnetic waves. These do not require a medium to travel though, so they can
travel through a vacuum. They are created by oscillating electric and magnetic fields. A few
examples of electromagnetic waves include light, radio waves, X-rays, and microwaves. Both
mechanical and electromagnetic waves have characteristics like wavelength, which the distance
between two corresponding points on consecutive waves, frequency which is how often the
waves pass a point in a certain amount of time, amplitude which is the height of the wave,
indicating energy, and speed which is how fast the wave travels through the medium. These
properties help define how the wave behaves and interacts with other waves and materials.
Wave interference is the phenomenon that occurs when two waves meet while traveling
along the same medium. When the waves overlap, they combine to form a new wave pattern,
often referred to as a wave interference pattern. There are two main types of wave interference;
constructive interference and destructive interference. Constructive Interference occurs happens
when the crest (highest point) of one wave aligns with the crest of another wave, or the troughs
(lowest points) align with the troughs of another wave. As a result, the waves amplify each other,
creating a wave with a higher amplitude. Destructive Interference, occurs when the crest of one
wave aligns with the trough of another. They cancel each other out, leading to a lower amplitude
or, in some cases, complete cancellation if the waves are of equal intensity. Interference can
occur with any type of wave, so it is utilized as the core principle behind many technologies and
natural phenomena, from noise-canceling headphones to the colorful patterns oil makes when it
sits on water.
Young's Double-Slit Experiment is a famous physics experiment that demonstrates the
interference patterns of light waves. It was conducted by Thomas Young in 1801 and became a
key piece of evidence in the debate over whether light behaves as a wave or a particle. In Young's
experiment there is a single light source, such as a laser or sunlight filtered through a single slit,
directed at a barrier with two parallel slits cut into it. This ensures that the light waves reaching
the slits are in phase. The two parallel slits in which the light passes through, acts as a new
source of light waves. These waves then spread out, or diffract, as they pass through each slit. An
interference pattern can be observed from this experiment as the diffracted light waves from the
two slits travel to a screen behind the slits. They overlap and interfere with each other, creating
regions of constructive interference, which creates bright spots on the screen, and destructive
interference, which creates dark spots. This produces a series of alternating bright and dark
bands on the screen, known as interference fringes. Young’s experiment produced several
observations. For example, this particular interference pattern of alternating bright and dark
bands suggested that light waves interact in a wave-like manner, reinforcing or canceling each
other out as they overlap. This was strong evidence for light’s wave nature, as particles alone
would not create such patterns. The second observation that was made was wave-particle
duality. When individual photons pass through the slits one by one, they are able to form an
interference pattern over time, suggesting each photon behaves as a wave and interferes with
itself. Young’s Double-Slit Experiment was crucial in advancing the wave theory of light and laid
the groundwork for quantum mechanics, and it is now also used as a model to demonstrate how
all particles, not just light, have wave-like properties.
The destructive interference region in an interference pattern is commonly expressed as
the dark regions, whereas the constructive interference is commonly referred to as the bright
regions. This is due to the fact that, as seen in Young’s Double-Slit Experiment, the brightness of
light is proportional to the amplitude of the wave. To explain, in areas where destructive
interference is occurring, the amplitude is decreased, making the light less bright. On the other
hand, in areas where constructive interference is occurring, the two light waves add together,
meaning that their amplitudes also combine, leading to a significant increase in intensity, which
appears as a bright spot to the human eye.
Wave interference in water has unique characteristics because water waves are
mechanical waves that require a physical medium, in this case water, to propagate, unlike light
waves which are electromagnetic and can travel in a vacuum. One unique aspect of water wave
interference is that water waves are on a surface, inherently two-dimensional, with both
horizontal and vertical displacements. When two water waves interfere, you see interference
patterns on the water surface, creating visible regions of constructive and destructive
interference. This differs from sound or light waves which are three dimensional, where
interference effects aren’t as visible in a medium. Another interesting aspect is the amplitude
and energy dissipation nature of water waves. Water waves lose energy as they propagate due to
frictional forces within the water and the air above. This energy dissipation causes the amplitude
to decrease over time and distance, making interference effects and patterns less pronounced
farther from the source of disruption. In contrast, light waves don’t dissipate energy in the same
way because they are not slowed by friction in a vacuum. The third aspect that makes water
wave interference unique is that it uses gravity as a restoring force. The behavior of water waves
is influenced by gravity, which acts as a restoring force that pulls water back to its original level.
This creates a different kind of interference pattern than in sound or light waves, where the
restoring force isn’t gravity. This influence of gravity causes water waves to oscillate at a
frequency that depends on both the wavelength and the depth of the water, which leads to more
complex interference patterns, especially in shallow water. And finally, another unique aspect is
the visibility and tactility of the interference patterns. Interference patterns in water waves are
not only visible but can also be felt physically if you’re in the water. This makes water wave
interference highly experiential, unlike interference with light, which is only visual, or sound,
which is auditory. The physical interaction allows for tangible observation of patterns, and
therefore is a good way to visualise wave interference.
Water wave interference observation plays a significant role in several real-world
contexts, especially in fields related to engineering, environmental science, and coastal
management. Engineers study wave interference to design coastal structures like breakwaters
and groins that minimize destructive wave impacts on shorelines, or design harbors that limit
wave energy, creating calmer waters. This phenomenon is also important in the field of Surf
Science and Wave Forecasting to predict wave heights and patterns as well as when and where
the best waves will form, making use of ocean buoys and wave-tracking technology.
Additionally, this phenomenon also influences the distribution of nutrients and oxygen in
coastal and shallow water ecosystems. Studying wave interference patterns can help marine
biologists learn about areas of nutrient-rich waters which benefit marine life, or conversely,
zones that might limit water circulation, potentially affecting oxygen levels for organisms. And
finally, wave interference principles are applied in underwater noise cancellation technologies to
reduce the impact of human-made noise on marine life. By creating waves that destructively
interfere with noise, engineers and marine scientists can help protect marine animals sensitive
to sound. Overall, studying the principles of water wave interference can assist in many fields,
even contributing to the reduction of human damage on marine ecosystems.
- Research Question
How does the distance between two slits affect the interference pattern of water waves,
simulated in a water tank?
- Hypothesis
If the distance between two slits in a water container increases, then the distance between points
of constructive interference (bright regions where waves add together) and the destructive
interference (dark regions where the waves are out of phase with each other) will also increase
because a larger slit distance causes wider wave separation. Direct, inverse relationship.
- Variables
Independent Variable: The distance between 2 slits in a water container.
Dependent Variable:
● The distance between points of constructive interference
● The distance between points of destructive interference
Control Variables:
Control Variables
Impact on experiment
Method to ensure a certain
level of control over the
variable
The medium of which the
waves are traveling in.
If I am not consistent with
I will be using tap water from
the medium I am utilizing,
the sink for each trial.
the density and overall
characteristics might differ,
leading to an unfair
experiment. For example, If I
used oil for one trial and
water for another, the density
of the medium differs which
will contribute to the overall
imprecision and inaccuracy of
the results.
The volume of the water in
the container.
The volume of water in the
container determines the
depth of the water. This can
affect the amplitude,
wavelength, and frequency of
each wave. Also the
interference pattern that will
be visible on the piece of
paper that is underneath the
body of water will differ if the
volume of water is different
for each trial. The lines will
be less intense and visible if
the water is shallower.
I will use a measuring cup to
make sure that the volume of
water in the container stays
the same for each trial.
Frequency of the waves
The frequency of the waves
I will use a certain tool to
produced.
determine the wavelength as
well as the energy of each
wave. This will lead to
inconsistency and therefore
an imprecise experiment.
create the waves in the
simulation and use a
metronome so I know when
to create a wave.
Amplitude of the waves
produced.
The amplitude of the wave
determines the strength and
intensity of the wave. This
will lead to inconsistency and
therefore an imprecise
experiment. For example, if
the first wave has a high
amplitude and the second
wave has a lower amplitude,
the wave with the higher
amplitude has more energy
and therefore will have a
different wave interference
pattern than the next wave.
I will need to create a
mechanism which can
produce the same amplitude
of waves every time.
The materials used in each
trial.
The materials can affect
many things in this
experiment. For example, the
same material has to be used
to create the barrier in the
middle of the plastic
container because its
flexibility and thickness can
affect the experiment.
Another example is the
container of which the water
is going to be. The
dimensions, the shape, and
the overall material that it is
made out of can make a
difference in the results.
I need to make sure I use the
same equipment and
materials for each trial.
The method used in each
trial.
The method and order of
things I do for the procedure
of this experiment can affect
the results. For example, If I
take pictures of the
experiment before I actually
create the waves, that would
not be an effective
experiment.
I will make sure that I follow
the method for each trial of
the experiment.
Distance from the slits to the
measurement area.
Energy disperses as the wave
travels so the point of
disruption in the water must
I will set a fixed point and I
will be taking the
measurements and making
The width of the slits.
be the same for each trial of
this experiment.
sure that the slits don't move
around.
The width of the slits will
determine the diffraction as
well as the intensity of the
interference pattern. For
example if the slits are wider,
the wave interference pattern
will be blurrier and more
unclear and the wave will
travel in a straighter line.
I will make sure that I use a
ruler to measure the width of
the slits.
- Materials
● Water (2.5 L)
● Clear Plastic Tray (1)
https://www.amazon.com/PeoTRIOL-Stackable-Organizer-Certificate-Stationery/dp/B
0BZV76FY3/ref=sr_1_14_sspa?crid=2QWMJVD9LV2CV&dib=eyJ2IjoiMSJ9.fhwdpkL1
o_BMEBkT6A2_qq9RSFd2EYVo_eGvSLSw5Y8Zivd7vf-kGH30qkB9KmeMN0w0rgmm
sA0c-dRymRizQj39pTNzoo9bJh7-5TzK88EolE480Rm5a3ZG28RTl3IcJbJNrMcyG1dAw
wbtpPtrrtcpqHr5IEc6fD0MQt3BI2WJkHv4nem7TC-4VSe0yNENEeiJpMu7EucpFJU7l
HdxwtKSEK74GMadGOjcf6uz7AGq_LL_t5ZfSv906TK2l7Zf5yuqXb1S66M6TLxi30uddV
cbIBeFYLEhgqr1io0paYw.L0BXb1AwnfnfsDYFD1U0rI2mGRQoBYzCG--qq8rU2q8&dib
_tag=se&keywords=Shallow%2BContainer&qid=1730776423&sprefix=shallow%2Bcont
ainer%2B%2Caps%2C294&sr=8-14-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9tdGY&th=1
● Light (1)
● Foam board (1)
https://www.amazon.co.jp/-/en/Styrofoam-Board-inches-Thickness-sheets/dp/B0C8T4
7N5D/ref=sr_1_6?dib=eyJ2IjoiMSJ9.N_hXYgkrHlZSSlKM2Z-WbiSfpbuiJJVYfjD512Xd
BVhDxtBUIwSY0bW5damsabdEzQheJUDtj83iFy95EhyAgH1DUk4kl_yNgjPQTOCPh1r
A_yh8w9W67s_OmmebBmaYBhdQC6xV2JPbhgl8jopnLMrRwG0v88-GTgsk2ZjG2xtC8
uJZEXbS1sezl-yMN9RXkEqFa56t-m2Diw7T4-YmVPCuWhsuewXABtaIUsSSTsYNh9fN
qVIg22-5o8zesbb9PHUiT8qUfeLZDR8QOQnQxYYADWvjGIKPCNwrdIA4-iE.Mb0CLV
DruPeKNVz04VoS43r5MLl8kQq798fEi_ZwkNg&dib_tag=se&keywords=foam+board+
no+paper&qid=1730776245&s=office-products&sr=1-6
● 100mL beaker (Smallest graduation: 2 ml, uncertainty of 1 measurement: 1ml) (1)
● A3 Grid paper (1)
● 15 cm ruler (Smallest graduation: 1 mm, uncertainty of 1 measurement: 0.5 mm) (2)
● Plastic baskets (height of 20cm) (3)
● Tape (1)
● Scissors (1)
● Cutter (1)
● Pencil (1)
● Marker (Able to use on multiple surfaces) (1)
●
●
Plastic Folder
Phone/camera (1)
- Method
1.
Create the Simulation
1.1.
Place an A3 piece of grid paper on a flat surface.
1.2.
Place 3 plastic baskets that are flipped upside down so that the base is on top, on
3 sides of the grid paper.
1.3.
Cut out a rectangle with widths 36 x 24 (cm) in the foam board. Make sure it is
centered on the foam board.
1.4.
Place this foam board on top of the plastic baskets, above the piece of grid paper.
1.5.
Insert the plastic tray in the rectangular hole in the foam board.
1.6.
Place a lamp or a light on the upside down plastic baskets so that the light is
shining on to the plastic tray.
1.7.
Pour 2.5L of water into the plastic tray, making sure to use a 100mL beaker.
1.8.
Cut 5 rectangular strips with dimensions 25 x 8 (cm) from the plastic folder. Cut
2 slits in each piece, all of them 0.5 cm in width. The first piece with slits that are
2 cm apart, the second with slits that are 4 cm apart, the third with slits that are 6
cm apart, the fourth with slits that are 8 cm apart, and the last strip with slits that
are 10 cm apart.
1.9.
Cut a slit on either side of the plastic strips, 0.5 cm away from opposite edges.
This is so it can be slid on to the edge of the plastic tray.
2.
Begin the experiment
2.1.
Insert the strip of plastic folder with slits that are 2 cm apart onto the plastic tray.
Make sure that it is in the center of the tray.
2.2.
Use tape to make sure it does not move around.
2.3.
Turn the lamp on.
2.4.
Set up a recording device (phone/camera) beneath the plastic tray on the side
where the plastic basket is not there, pointing the lens at the grid paper. Press
record.
2.5.
Using one of the 15 cm rulers, disturb the water on one side of the plastic strip in
a back and forth motion, making sure that the disruption is creating waves on the
other side of the plastic folder strip.
2.6.
Repeat the back and forth motion 5 times, each time making sure that the water
has calmed down to its original state before starting the next. Observe the
interference pattern that will show up on the grid paper.
2.7.
Repeat steps 2.1, 2.2, skip to 2.5, and 2.6 with the other plastic folder strips. Start
with the strip with the smallest distance between the two slits and end with the
strip with slits that are 10 cm apart.
2.8.
Stop the recording.
3.
Collect Data
3.1.
Look back at the recording that was taken for the experiment.
3.2.
3.3.
3.4.
3.5.
3.6.
3.7.
4.
Identify when the waves were made and take a screenshot of the frame.
Optional: print out the screenshots that were taken.
With a 15 cm ruler, measure the distance between 2 dark regions.
Repeat step 3.4 but measure the distance between 2 bright regions.
Repeat steps 3.4 and 3.5 for all 5 plastic folder strips with 5 different distances
between each slit, with 5 trials each.
Collect and organise data into a table and graph.
Safety Tips.
4.1.
Make sure that the lamp/light is not exposed to the water since it is very
dangerous.
4.2.
Make sure that when packing away the experiment, the water is not spilt on to
charging ports or any electronics. The water can also make the floor slippery.
- Results
Table 1: The Distance Between Points of Interference (cm) for Difference Distances Between 2
Slits (2,4,6,8,10 cm). Data extracted from experiment.
Distan
ce
betwe
en the
slits
(cm)
Type of
Wave
Interfere
nce
(Constru
ctive/Des
tructive)
2
Construc
tive
1 mm
Destructi
ve
1 mm
Construc
tive
1 mm
Destructi
ve
1 mm
Construc
tive
1 mm
Destructi
ve
1 mm
4
6
Distance Between Points of
Interference (cm)
Trials
1
2
3
4
5
Mean
Distan
ce
Betwe
en
Points
of
Interf
erence
(cm)
Small
est
Gradu
ation
Uncer
tainty
of One
Measu
remen
t
Overal
l
Uncer
tainty
8
10
Construc
tive
1 mm
Destructi
ve
1 mm
Construc
tive
1 mm
Destructi
ve
1 mm
Graph 1: The Distance Between Points of Interference (cm) for Difference Distances Between 2
Slits (2,4,6,8,10 cm). Data extracted from experiment.
- Analysis
- Conclusion
It is very difficult to identify any patterns to make any observations referring to the data that was
extracted from this experiment. However, there are formulas that have been developed to
calculate the distance between points of both constructive and destructive interference. Here
are the 2:
Formula for Constructive Interference (Bright Spots)
λ𝐿
Δ𝑥 = 𝑚 𝑑
Formula for Destructive Interference (Dark Spots)
1
λ𝐿
Δ𝑥 = (𝑚 + 2 ) 𝑑
By using these formulas, an identification can be made about the differences between the data
collected in this experiment and the data collected from the formulas and judge on the
experiment's accuracy and precision.
Table 2: The Distance Between Points of Interference (cm) for Difference Distances Between 2
λ𝐿
Slits (2,4,6,8,10 cm). Expected results, using the formula Δ𝑥 = 𝑚 𝑑 for constructive
1
λ𝐿
interference and Δ𝑥 = (𝑚 + 2 ) 𝑑 for destructive interference. Δ𝑥 = Distance Between
Points of Interference, m=Fringe order, L=14cm, 𝝺=1cm,
Width
between the
slits
(represented
as d in the
formula)
Fringe order
(represented as m
in the formula)
Type of Wave Interference
(Constructive/Destructive)
Distance Between
Points of Interference
(represented as Δ𝑥 in
the formula)
2 cm
0
Constructive
0.0 cm
1
2
3
4
5
4 cm
0
1
2
3
4
5
6 cm
0
1
Destructive
3.5 cm
Constructive
7.00 cm
Destructive
10.5 cm
Constructive
14.0 cm
Destructive
17.5 cm
Constructive
21.0 cm
Destructive
24.5 cm
Constructive
28.0 cm
Destructive
31.5 cm
Constructive
35.0 cm
Destructive
38.5 cm
Constructive
0.0 cm
Destructive
1.75 cm
Constructive
3.5 cm
Destructive
5.25 cm
Constructive
7.0 cm
Destructive
8.75 cm
Constructive
10.5 cm
Destructive
12.25 cm
Constructive
14.0 cm
Destructive
15.75 cm
Constructive
17.5 cm
Destructive
19.25 cm
Constructive
0.0 cm
Destructive
1.17 cm
Constructive
2.33 cm
2
3
4
5
8 cm
0
1
2
3
4
5
10 cm
0
1
2
Destructive
3.5 cm
Constructive
4.67 cm
Destructive
5.83 cm
Constructive
7.0 cm
Destructive
8.17 cm
Constructive
9.33 cm
Destructive
10.5 cm
Constructive
11.67 cm
Destructive
12.83 cm
Constructive
0.0 cm
Destructive
0.88 cm
Constructive
1.75 cm
Destructive
2.63 cm
Constructive
3.5 cm
Destructive
4.38 cm
Constructive
5.25 cm
Destructive
6.13 cm
Constructive
7.0 cm
Destructive
7.88 cm
Constructive
8.75 cm
Destructive
9.63 cm
Constructive
0.0 cm
Destructive
0.7 cm
Constructive
1.4 cm
Destructive
2.1 cm
Constructive
2.8 cm
3
4
5
Destructive
3.5 cm
Constructive
4.2 cm
Destructive
4.9 cm
Constructive
5.6 cm
Destructive
6.3 cm
Constructive
7.0 cm
Destructive
7.7 cm
Graph 2: The Distance Between Points of Interference (cm) for Difference Distances Between 2
Slits (2,4,6,8,10 cm). Expected results, using the formula for constructive interference and
destructive interference.
Table 3: The Difference between the expected results and the data collected in the experiment.
Width
Fringe
between order
the slits (represe
nted as
m in the
formula)
Type of
Wave
Interference
(Constructiv
e/Destructiv
e)
2 cm
Constructive
0.0 cm
Destructive
3.5 cm
Constructive
7.00 cm
Destructive
10.5 cm
Constructive
14.0 cm
Destructive
17.5 cm
Constructive
21.0 cm
Destructive
24.5 cm
Constructive
28.0 cm
Destructive
31.5 cm
Constructive
35.0 cm
Destructive
38.5 cm
Constructive
0.0 cm
Destructive
1.75 cm
Constructive
3.5 cm
Destructive
5.25 cm
Constructive
7.0 cm
Destructive
8.75 cm
Constructive
10.5 cm
Destructive
12.25 cm
Constructive
14.0 cm
Destructive
15.75 cm
Constructive
17.5 cm
0
1
2
3
4
5
4 cm
0
1
2
3
4
5
Data Collected
in the
Experiment
Data extracted
from using the
formula
Difference
6 cm
0
1
2
3
4
5
8 cm
0
1
2
3
4
5
10 cm
0
Destructive
19.25 cm
Constructive
0.0 cm
Destructive
1.17 cm
Constructive
2.33 cm
Destructive
3.5 cm
Constructive
4.67 cm
Destructive
5.83 cm
Constructive
7.0 cm
Destructive
8.17 cm
Constructive
9.33 cm
Destructive
10.5 cm
Constructive
11.67 cm
Destructive
12.83 cm
Constructive
0.0 cm
Destructive
0.88 cm
Constructive
1.75 cm
Destructive
2.63 cm
Constructive
3.5 cm
Destructive
4.38 cm
Constructive
5.25 cm
Destructive
6.13 cm
Constructive
7.0 cm
Destructive
7.88 cm
Constructive
8.75 cm
Destructive
9.63 cm
Constructive
0.0 cm
1
2
3
4
5
Destructive
0.7 cm
Constructive
1.4 cm
Destructive
2.1 cm
Constructive
2.8 cm
Destructive
3.5 cm
Constructive
4.2 cm
Destructive
4.9 cm
Constructive
5.6 cm
Destructive
6.3 cm
Constructive
7.0 cm
Destructive
7.7 cm
Graph 3: The Difference between the expected results and the data collected in the experiment.
- Evaluation
As visible in the data table 1, 2 and 3 as well as data graph 1, 2 and 3, the results are very
inaccurate and imprecise. There were many flaws in this experiment that made my experiment
extremely unreliable.
1. First of all, it was very difficult to extract any data from my experiment, due to the
materials I decided to use. For example, I used plastic sheets and cut slits into them to
use as the point of interference. This was not ideal for 3 reasons. Firstly, because it was a
flexible material, once I created waves on one side of the plastic sheet, the plastic sheet
created waves of its own on the other side. It was very difficult to keep it from bending
back and forth. This affected the results because it created more disturbances in the
water that showed up in the data extraction process and overall made the experiment
unreliable. The second issue with this material was that it was very difficult to cut
accurate slits. The width of each slit was supposed to be 0.5 cm but the only thing I could
use to mark the lines of which I needed to cut out was by using a marker. The lines of the
marker were too thick so each time I tried to cut accurate and precise lines, the results
were always different. The inconsistency in this control variable made the experiment
unreliable because the width of the slit can affect the interference pattern. The third
problem of this material was that it was difficult to stick it to the container in a straight
line. Again, because of the flexibility of this material, it was very difficult to stick the film
onto the container on the straight line in the middle. It kept bending and moving around
as I created more waves, which led to the unreliability of these results. If I were to
replace this material with another to create a more reliable experiment, I would use a
material that is stiffer and would be able to be marked with a finer line for a more
accurate cut, for instance a metal panel. However, I would need power tools to create the
slits in the panels which would mean a longer process. Another material that caused
issues was the plastic container. The plastic container I used was supposed to be used for
storage and organization purposes in an office environment, not for a science
experiment. The base of the container had marks and dents which created shadows onto
the piece of paper. Also, it was not completely flat, resulting in the bending of light in
some areas. Another flaw of this material was its size, more specifically it was too small.
The waves in the water reflected off the other sides, creating more disturbances in the
water, making it difficult to see the initial interference pattern. As a replacement for this
material, I would use a plastic container that is meant to be used for science experiments.
2. Second of all, the results of my experiment are unreliable, due to the method I decided to
use. First, I was unable to create waves of the same frequency, wavelength, and
amplitude each time I did the trail because there was no mechanism to create these
waves. I used a ruler and created random waves in the container with different forces
and frequencies for each trial. This led to inconsistent waves and inaccurate
measurements. Another issue, the point of which I created the waves for each trial was
different. As explained in the Control Variable section of this report, this variable was
important to keep the same for this experiment because energy disperses as the wave
travels. However, one thing that was done well in terms of the method was the
preparation of the experiment. With the materials and time that was available, the set up
of the experiment was quite detailed and thought out, but not enough for the results to
be reliable.
3. Third of all, the data extraction process led to inaccurate results. This issue was created
because of both the materials and the method I utilised. My original plan was to take
pictures from above the plastic container containing the water and place my phone
parallel to the surface of the paper underneath the bottom. However, the waves were
very unclear and couldn’t be seen from the top of the plastic container because of the
water and the light that was reflected off it, so I had to place my phone at an angle to the
paper which led to an inaccurate reading. Also the distance of the phone to the piece of
paper and the angle differed each time so even if I printed out the frames from the
videos, and measured the wavelengths of the waves, it would be impossible to get a
reliable result. However, one thing I think helped with this situation was the fact that
there was a grid paper instead of a plain sheet of paper underneath the plastic container.
This helped with the measuring process to a certain extent.
Overall, this experiment produced very unreliable and inaccurate results due to the materials,
method, and data extraction I used.
- Real World Application
Water wave interference plays a significant role in several real-world contexts, especially
in fields related to engineering, environmental science, and coastal management. One example
in which the phenomenon plays a vital role is in coastal engineering and erosion control
research and technologies. Interference patterns of water waves influence coastal erosion and
sediment transport. Engineers study wave interference to design coastal structures like
breakwaters and groins that minimize destructive wave impacts on shorelines. By positioning
these structures strategically, they can encourage destructive interference, reducing wave energy
that reaches the shore and thereby protecting against erosion​. Another example is designing
harbors and ports. Interference from incoming waves can affect port operations and ship
stability. Engineers use knowledge of wave interference to design harbors that limit wave
energy, creating calmer waters. This is crucial in locations where strong, consistent wave
interference patterns could make navigation and docking dangerous. Controlled interference
helps create safer and more efficient harbor conditions. This phenomenon is also important in
the field of Surf Science and Wave Forecasting. Wave forecasters rely on an understanding of
constructive and destructive interference to predict wave heights and patterns. For example,
areas with constructive interference produce higher waves, which are ideal for surfing.
Forecasting models use interference patterns to predict when and where the best waves will
form, making use of ocean buoys and wave-tracking technology. Additionally, it is related to
research done for the human impacts on the marine environment and ecosystems. Interference
patterns also influence the distribution of nutrients and oxygen in coastal and shallow water
ecosystems. Certain interference patterns can enhance the upwelling of nutrient-rich waters,
which benefits marine life. Conversely, interference that creates large, calm zones might limit
water circulation, potentially affecting oxygen levels for organisms like fish and coral reefs. And
finally, wave interference principles are applied in underwater noise cancellation to reduce the
impact of human-made noise (like from ships or construction) on marine life. By creating waves
that destructively interfere with noise, engineers and marine scientists can help protect marine
animals sensitive to sound, such as whales and dolphins. Studying water not only helps in
managing natural forces but also aids in creating a safer and more sustainable environment for
both humans and marine ecosystems.
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