What are Ocean Currents? - Definition & Types

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Ocean Upwelling: Definition & Types

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:00 Definition of Ocean Currents
  • 0:59 Surface Currents
  • 3:12 Deep Water Currents
  • 4:25 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Lisa Roundy

Lisa has taught at all levels from kindergarten to college and has a master's degree in human relations.

Currents are responsible for circulating water throughout the earth's oceans. This lesson will discuss surface ocean currents, deep water ocean currents, and the forces that drive them.

Definition of Ocean Currents

Imagine you fill a bathtub with cold water then add hot water at one end. You will not have warm water until it is mixed. Put your hand in the hot water and push it toward the cold end of the tub. You can feel the movement and the difference in water temperature. You created a small current in your bathtub by causing the water to move from one place to another.

Much larger currents are at work in our oceans, circulating water around the world. These ocean currents, which are massive currents that are influenced by a variety of different forces that act to propel the water both on the surface and in deep ocean waters. This movement has a significant effect on the earth's weather. For example, the Gulf Stream current carries warm water toward northern Europe. Due to this, coastal countries in northern Europe have a milder winter than coastal areas in the northeast United States that are much farther south.

Surface Currents

Currents found in the upper 1,300 feet of the ocean are called surface currents. Let's examine some of the forces that determine the direction of these currents.


The surface of the ocean is not even. Due to this, gravity has an impact on the flow of water in the ocean. The earth's gravity pulls at water, causing it to flow downward from higher surface levels. You will notice the impact of gravity as it is mentioned alongside various other forces throughout this lesson.


Wind is the driving force behind our oceans' surface currents. In other words, most surface currents are caused by wind, which has the greatest impact on these currents. As the wind blows over the water's surface, it produces friction. This friction pushes the water along and forms a current moving in the same direction the wind is blowing. The current will continue in the direction of the wind until other factors - such as nearing a land mass or colliding with another ocean current - cause the water to build up and move in different ways.

Coriolis Effect

The spinning of the earth deflects movement. This is called the Coriolis Effect . We usually see no impact from the spinning of the earth, but we do notice its effect on surface currents because they are large and move over long distances. The Coriolis Effect comes into play when water being pushed by the wind piles up into mounds. As gravity pulls the water down the slope of the mound, the Coriolis Effect forms a current that creates spiral patterns called gyres that help push the current forward. These gyres move clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

Continental deflection

We briefly mentioned earlier that nearing a land mass is one factor that causes water to build up and change direction. When water building up or changing direction occurs near a very large land mass, or continent, it is called continental deflection. Since the earth is not completely covered in water, continental deflection plays a large role in the overall direction of surface currents. The water can't travel over or through the continent, so it is forced to move around it.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account