Login
Copyright

Capillary Action of Water: Definition & Examples

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Conversion Factor in Chemistry: Definition, Formula & Practice Problems

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

Take Quiz Watch Next Lesson
 Replay
Your next lesson will play in 10 seconds
  • 0:00 What is Capillary Action?
  • 0:55 Contributing Properties
  • 2:14 Examples
  • 3:29 Try This At Home!
  • 4:13 Lesson Summary
Add to Add to Add to

Want to watch this again later?

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

Login or Sign up

Timeline
Autoplay
Autoplay
Create an account to start this course today
Try it free for 5 days!
Create An Account

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Mary Ellen Ellis
Capillary action is an important ability of water to move through other materials. Water is not the only liquid that can do this, but its properties make it better at capillary action than most other substances.

What Is Capillary Action?

If you put a narrow straw into a glass of water, what can you observe about the level of water in the straw as compared to in the glass? You should see that the water has climbed up the straw and is higher than the level of water in the glass. It seems to have defied gravity by moving up the straw. This is capillary action - the movement of a liquid through or along the surface of another material in spite of other forces, such as gravity.

Capillary action is a property seen in some liquids. It is most pronounced in water because of water's unique properties and because water is the basis of most liquids that we use every day. When you use a paper towel to mop up a spilled drink or use a towel to dry yourself after a shower, you are using capillary action. When you put cut flowers in a vase of water, capillary action keeps them fresh.

Contributing Properties

Water is good at capillary action, better than most liquids. How well a liquid can perform the feat of capillary action depends on cohesion and adhesion. Cohesion is the attraction between particles of the same type. There is strong cohesion in water. One water molecule is strongly attracted to another. Adhesion is the attraction between two different particles. The adhesion between water molecules and a plastic straw is also pretty strong.

Capillary action occurs when adhesive forces outweigh cohesive forces. Although water molecules are pretty strongly attracted to each other, they are also attracted to the plastic of the straw. The result is that water molecules will climb up the surface of the interior of the straw and the level of the water is slightly higher within the straw. There is even better adhesion between water and glass. If you had a glass straw of the same size as the plastic straw, you would see the water level rise even higher.

So why doesn't the water climb the sides of the glass, you might be asking? It does, but only a little bit. The wider the vessel, the more the cohesive forces between water molecules will take over and keep water from climbing the sides of the glass. The narrower the vessel or tube, the greater the effect of capillary action.

Examples

You may have seen this happen if you have ever donated blood. Before you can donate, the nurse will prick your finger to get a sample of your blood for testing iron levels. He or she will place a narrow glass tube, called a capillary tube, where your finger was pricked. Your blood quickly moves up the tube. It looks like the nurse has sucked your blood out with that tube, but it's really only capillary action. This demonstrates capillary action of water because your blood is largely made of water.

Another example of capillary action is in your eyes. The tear duct in the corner of each eye is a narrow tube that uses capillary action to drain excess tears into the nasal passage. And how do plants, including the tallest trees, get water from their roots all the way out to branches and leaves against the force of gravity? Capillary action.

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

Register for a free trial

Are you a student or a teacher?
I am a teacher
What is your educational goal?
 Back

Unlock Your Education

See for yourself why 10 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back

Earning College Credit

Did you know… We have over 95 college courses that prepare you to earn credit by exam that is accepted by over 2,000 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? Study.com 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 free for 5 days!
Create An Account
Support