Study Guide: Ch.14 – The Movement of Ocean Water KEY
1. What was Thor Heyeredahl trying to prove on his voyage across the ocean?
Thor Heyerdahl sailed a raft using only the wind and currents for more than 6000 KM in order to prove
that the Ancient Peruvians used currents to settle in the Polynesia.
2. What does the Gulf Stream transport?
The Gulf Stream transports warm water currents from equator north into Europe. It transports more
water than any other river.
3. How do winds blow across the equator?
Near the equator, winds blow East to West… Near the poles, wind blows West to East
4. Define the Coriolis Effect and explain how it works.
Definition: The apparent curving of the path of a moving object from an otherwise straight path due
to the Earth’s rotation
This causes the wind to blow in clockwise patterns in the Northern Hemisphere and Counter-clockwise
in the Southern Hemisphere
5. List the major surface currents that are deflected by North and South America.
Brazilian Current, Gulf Stream Currents
6. Describe the temperature and density differences between surface currents and deep currents.
Surface Currents are controlled by wind. They can be cool or warm currents. Cool currents originate
from the poles, warm from the Equator.
Deep currents are affected by salinity and temperature. Cooler temperatures=more dense.
Warmer temperature = water rises (less dense)
Higher salinity = more dense
Lower salinity = less dense
Deep currents are colder and denser than surface currents
7. How are coast lines affected by warm-water currents?
Warm water currents affect the coastlines by producing warmer climates at a higher latitude
(example England and Iceland versus Canada)
8. Describe the positive and negative effects of El Niño.
Positive: Warmer Temperatures, rain in areas where there is often drought
Negative: Flash Floods in areas where land is dry, landslides, droughts in normally moist areas. Also, it
impacts crops and tourism.
9. Define the following parts of a wave: crest, trough, wavelength, and wave height.
Crest- the highest part of a wave
Trough-the lowest part of a wave
Wavelength- the vertical distance between two adjacent high or low points of a wave
Wave height- the vertical distance between the highest and lowest points of a wave
10. How is wave speed calculated?
Wavelength/wave period = wave speed
11. How does the motion of a wave change as it approaches the shore?
1. As deep water waves become shallow water waves, the water particles slow down and build up.
2. Deep water waves become shallow water waves when they reach water shallower than half their
wavelength.
3. When they get shallower and interact with the ocean floor, the waves get higher.
4. Gravity then eventually pulls the water down causing the wave to “break” and crash into the ocean
floor.
The area between the breaker zone and the shore is called the surf.
12. What is an undertow?
An undertow is a subsurface current that is near shore and that pulls objects out to sea. It flows in the
opposite direction as the wave.
13. How does an earthquake cause a tsunami?
A tsunami occurs when an earthquake occurs under water. The movement of the earth causes a
tsunami. This forces a large amount of water up or down.
14. Draw and label the characteristics of a wave.
15. List 3 facts about surface currents and 3 facts about deep currents.
Surface Currents
1. East to west near the equator, west to east near the poles
2. Zero to several hundred meters, warm or cool
3. Controlled by three factors – Global winds, coriolis effect, and continental deflection
Deep currents
1. Also called density currents – not controlled by wind
2. Temperature and salinity affect the currents
3. Form by decreasing temperature, increasing salinity through freezing, and increasing salinity
through evaporation16. How do currents affect the temperature and weather on land?
Warm water currents affect the coast by making the land warmer and more moisture
Cool water currents can cool the land down bringing rain or snow.
17. Draw the water cycle. Include labels at each step.
(See diagram in your folder/binder)
18. Draw a diagram of the ocean floor. Please include the major features.
(See diagram in your folder/binder)
19. How does ocean pollution in one area of the world affect other areas?
CURRENTS!