16-2 Flashcards
What are waves?
Rhythmic movement that carries energy through matter or space
In oceans, the energy wave moves through seawater.
What causes waves?
Winds, earthquakes, and gravitational force of the moon and sun
These factors contribute to the formation of waves.
What visible evidence indicates energy passing through water?
Water waves
These are commonly seen in the ocean due to wind.
Define ‘crest’ and ‘trough’ in wave characteristics.
crest: Highest point of a wave
trough: Lowest point of a wave
what is wave height and wavelength?
wave height: Vertical distance between crest and trough. amount of energy and strength depends on it
wavelength: Horizontal distance between the crests or troughs
What distinguishes long wavelength waves from short wavelength waves?
Long wavelength waves are gentle rollers, short wavelength waves are choppy water
What is the period of a wave?
Time it takes for one full wave to pass a certain point
Define frequency and amplitude in relation to waves.
frequency: Number of waves that pass a point in a certain amount of time
amplitude: Half the distance of the wave height
How is energy related to amplitude?
Energy is equal to amplitude squared (E=amplitude^2)
What occurs to wave height and energy during storms?
Wave height increases a lot, but the amount of energy increases even more, causing damage
What causes water to pile up and form a wave?
Friction between wind and water
This movement begins when wind blows across a body of water.
What happens to waves when wind stops blowing?
Waves stop forming but continue moving for long distances
What factors determine wave height, length, and period?
- Speed (strength) of the wind
- Fetch (distance) over which the wind blows
- Length of time the wind blows
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What is wave motion in relation to water?
Waves can travel a great distance while water stays in about the same place except where it is cresting on the shoreline.
What happens to an object floating on water as waves pass?
It will rise and fall but does not move with the wave.
Describe the motion of water particles in a wave.
Water particles move in a circular orbital motion, swinging forward and downward, then back up to their original position.
How does energy move in wave motion?
Energy moves forward while water particles remain in the same place.
How does the depth of water affect wave motion?
Deeper water particles move in smaller circles compared to the surface due to the influence of wind.
What is the depth of wave motion relative to wavelength?
The depth of wave motion is half the wavelength.
What are swells in the context of waves?
Long low waves in deep water.
What are breakers?
swells approach shallow water.
What causes the height of waves to increase as they approach the shore?
Water on the bottom of a wave is slowed down by friction, causing crests to get closer together and wave height to increase.
What occurs when the tops of waves move faster than their bottoms?
The wave front collapses and turns into a breaker.
What happens after a wave breaks onto the shore?
Gravity pulls the water back into the sea, creating an undertow.
What are tides?
Regular changes in elevation of the ocean surface due to the moon.
What is gravity?
A mutually attractive force between any two objects.
What factors affect the strength of gravitational pull?
The masses of objects and the distances between them.
What is the relationship between the moon and Earth regarding gravity?
The moon and Earth exert gravitational forces on each other, with less pull when they are farther apart.
How does the distance from the moon affect gravitational pull on Earth’s surface?
Closer areas to the moon have more pull of its gravity, while further areas have less.
What is tidal range?
The difference between high tide and low tide.
What is high tide? what is low tide?
high tide: When the crest of a wave approaches, the sea level appears to rise.
low tide: When the trough approaches.
Why should tides be harnessed?
Tides can be harnessed to capture energy of wave motion, useful in large tidal ranges to generate electricity.
What is the primary cause of tides on Earth?
The moon’s gravity exerts a strong pull on Earth.
How does the moon’s gravitational force affect the oceans?
It pulls on water particles, causing a bulge on the side toward the moon (high tide).
What creates the second bulge of water on the side of Earth opposite the moon?
Inertia causes water to be ‘left behind’ as Earth is pulled more toward the moon.
What happens to water when high tides form?
Water is drawn away from areas between bulges, creating low tides.
Why does the sun have a lesser effect on tides compared to the moon?
The sun is larger but much farther away than the moon.
How does Earth’s rotation affect the timing of tides?
Different locations on Earth’s surface pass through high and low positions as Earth rotates.
What is the relationship between the east-west travel along the coast and high tide occurrence?
High tide occurs later the farther west you travel along the coast.
What factors can affect the height of tides in specific locations?
- Landforms can interrupt water movement
- A basin at a river’s mouth can increase tidal range
- Speed and depth increase as water flows into a narrower channel
What is a solar tide?
The sun pulls water on Earth’s surface toward it, creating a smaller tidal effect than the moon.
Define spring tides.
Tides that occur when the moon, Earth, and Sun are aligned during a new moon.
What are the characteristics of neap tides?
Smaller high tides and low tides that occur when the sun, Earth, and moon form a right angle.
How often do spring and neap tides occur each month?
Two spring and two neap tides each month.
What are the three types of tidal patterns?
- Diurnal: one high and one low tide each day
- Semidiurnal: two high and two low tides each day of similar size
- Mixed: similar to semidiurnal but with large inequality in high and low water heights
