Formation & Dissipation of Cloud Droplets

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: The Effect of Atmospheric Moisture on Climate Variability

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

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:01 What's a Cloud Droplet?
  • 1:01 Formation of Cloud Droplets
  • 3:15 Dissipation of Cloud Droplets
  • 5:34 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
Lesson Transcript
Instructor: Julie Zundel

Julie has taught high school Zoology, Biology, Physical Science and Chem Tech. She has a Bachelor of Science in Biology and a Master of Education.

Have you ever wondered why a cloud forms? Well, you've come to the right place! This lesson will explain why clouds form and will also examine why they disappear.

What's a Cloud Droplet?

Wally Water Molecule is back to teach you all about cloud droplets. You don't remember Wally, you say? Don't worry. I'll introduce you. Like his name implies, Wally Water Molecule is a water molecule, and he can exist as liquid water, solid water (aka ice) and a gas (or, water vapor). He is quite the world traveler and can be found in lakes and oceans, in the air, in clouds, in rain and even in snow! In fact, you might even see him change from a liquid to a gas, through evaporation, or change from a gas to a liquid through condensation.

Today you're in for a special treat: Wally is going to become a cloud droplet! A cloud droplet is water vapor that has condensed onto condensation nuclei. When you get a bunch of cloud droplets together, you have a cloud! But what are condensation nuclei? Well, let's start from the beginning.

Formation of Cloud Droplets

Once upon a time, Wally was hanging out in a beautiful blue lake. But, like all water molecules, Wally wasn't content just sitting around, so as soon as he had enough energy, he evaporated and became water vapor. Meanwhile, some of Wally's fellow water molecules were condensing. You might see some of them as dew on plants or as water droplets forming on a cold glass on a hot day.

Okay, back to Wally. The air can only hold so many of Wally and his buddies before it becomes saturated, which means the air is full of water vapor and can't hold anymore. And for every molecule of water that evaporates, one must condense. But what causes the air to become saturated, or full of Wally and his friends? Let's take a look.

  1. Evaporation - If the rate of evaporation has increased, there is more water vapor in the air; therefore, the air can become saturated.
  2. The air is cooled - As air is cooled, it can hold less water vapor before it becomes saturated. Technically it's a little more complicated, but the basic explanation is that more water vapor is found in warm air than in cold air.

Okay, so now you know what saturated means (and a couple of ways saturation can happen), so let's check back with Wally, who's still bouncing around in the atmosphere. Wally is now in saturated air, so he really wants to condense, but there is nothing to condense on in the atmosphere - or is there? Uh oh, it looks like Wally is about to bump into something. Look out!

Wally just collided with condensation nuclei, or tiny particles like dust, pollen, ash or bacteria that are floating in the atmosphere. And when Wally collides with these tiny particles, he's able to condense, turning into liquid water that is suspended in the air, otherwise known as a cloud droplet! So, cloud droplet formation just means water vapor condensed on condensation nuclei. If Wally and all of his friends become cloud droplets, they will collectively become a cloud.

Dissipation of Cloud Droplets

I'd like to say Wally and his friends lived happily ever after in that cloud, but all good things must come to an end. Unfortunately for that cloud, it's becoming a bright, sunny day. Wally and his friends are about to disappear and the cloud is going to dissipate. When the cloud droplet dissipates, it just means the cloud droplets evaporate. But what causes a cloud droplet to evaporate? I'm so glad you asked!

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