Unit 3: Waves and Tides
Name: ___________________________
Date: ________________ Pd: ____
Part 1 – Wave Basics
Please reference Lesson 23 (p. 442) in your textbook to supplement the following notes.
Where do ocean waves come from?
•
Anything through which energy flows is called a ___________________.
•
Ex: metal, string, water, land, air
•
A disturbance caused by the transfer of energy through a medium is called a ____________.
•
Source of energy for most waves is _____________.
Wave Structure
•
•
___________ – highest part of a wave
•
___________ – lowest part of a wave
•
Wave height – _________________ distance between a crest and its nearest trough.
•
Amplitude – equal to half of the wave height.
•
Wavelength – __________________ distance between two crests or troughs
If you look at the ocean in a cross section, surface wave would like a _________________ wave.
•
Transverse wave – motion of water is perpendicular to
direction of wave
•
It’s actually an ______________ wave – water is
moving a circular motion
•
Orbital motion
•
The size of the orbit of the water particles increases with
wavelength
•
The orbit size decreases rapidly with depth
•
Only "feel" waves to a depth of 1/2 of their wavelength
•
___________________________ wave – Motion of the
water moves parallel to the flow of energy.
•
Think slinky!
Wave Calculations
•
Period = time for wave to move
1 __________________
•
Frequency = ____ of waves passing fixed
point
•
Inverse relationship:
•
𝑝𝑒𝑟𝑖𝑜𝑑 =
1
𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦
•
1
𝑂𝑅 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 = 𝑝𝑒𝑟𝑖𝑜𝑑
Let’s practice:
What is the period for the graph? _________
What is the frequency for the graph? _________
What affects wave height?
1) Wind speed – How ______wind blows changes energy transfer & therefore wave height
2) Wind duration - How ______ wind blows changes energy transfer & therefore wave height
3) Fetch - ________ of ocean surface area affected by wind blowing in the same direction.
What affects how a wave breaks?
•
Type of __________, wind direction, slope of sea bed, sea floor ___________
How does a wave break?
•
Wave train approaches shore "_______" bottom at depth = 1/2 wavelength
•
Bottom of wave _________ even more as gets shallower, wave crest moves ahead of base of wave
•
When depth of water is ___ of wave height, it will break.
Deep water vs. Shallow water waves
•
•
Deep Water waves
•
The wave occurs in water deeper than half the
wavelength.
•
Not affected by ________________
Shallow Water waves
- Waves enter water that is equal to or less than _____
the wavelength
Types of Waves
•
___________ breaker: Found at gently sloping bottom.
•
___________ breaker: Found at moderate sloping bottom.
•
___________ breaker: So steep that wave doesn’t break until
right at shoreline.
More types of Waves
•
______________ – caused by plate shift on seafloor causing a
major displacement of water
•
_________ waves – Waves come together in positive interference
Part 2 – Tides
Reference Lesson 24 in your textbook to supplement these notes.
Causes: Moon’s gravity, Centrifugal force, Sun’s gravity
•
The Sun affects the Earth because it is so large, while the Moon's proximity to Earth is the main reason
for its role in the tidal cycle.
Daily Tides
•
High Tide:
- Occurs when the body of
water is in _______ with
the moon.
- Highest point water
reaches onto shore.
•
Low Tide:
- Occurs when the body of water in ________________ to the moon.
- Lowest point water reaches onto shore.
•
_____________: Distance between high and low tide.
- Affected by moon phase.
- Organisms must adapt to tidal range
- Highest tidal range = Bay of Fundy (16m or 52 feet)
- Ex: Sea turtles lay their eggs above the highest high tide.
Tidal movement
- __________ tide: Water moving
onshore from low to high tide.
• “Tide is coming in”
- ___________ tide: Water moving
offshore from high to low tide.
• “Tide is going out”
3 Basic Patterns of Tides
•
__________________ tide pattern
- Most areas on Earth experience this type
- ____high tides and ____ low tides
per day
•
____________ tide cycle
- One high and one low tide per day
•
Mixed Tide pattern
- Two highs and two lows per day but one set of tides is more ______________ than the
other.
Monthly Tides
1) Spring Tide
- Sun and moon __________ up and pull in the
same direction
- ___________ tidal variation between high and
low
- Occurs twice a month
- Occurs during ______ and ______ moon
2) Neap Tide
- Sun and Moon are lined up
_________________ (partially cancelling each
other out)
- __________ tidal variation
- Occurs twice a month
- Occurs during 1st and 3rd _______________ moons