 Hi, welcome to the MIPS, the Teen Center at the San Francisco Public Library. My name is Illiana and I am here to be your host for the STEM Challenge Yourself series, where our inspiring librarians come up with science experiments that you can try at home. In today's challenge, you're going to learn about the science of clouds. So watch closely and pay attention. Take it away. Hi guys, I'm librarian Kimberly. Have you ever wondered what clouds are made of and how all that water gets up in the sky? Well, today we're going to make our very own rain clouds and then we're going to see if we can make it rain. We're also going to have a lot of fun playing with shaving cream and food coloring. So for today's experiment, you're going to need some shaving cream. You want the white foamy kind, not the gel kind, some water, some food coloring. You might get a little bit on your hands. If you do, just wash it off. If you get some stuck on there, it'll just last a day or two and then it'll go away. And then you'll need three small bowls or containers and three eyedroppers. If you don't have eyedroppers, or you can just use one eyedropper, but if you don't have any eyedroppers, you can use a quarter teaspoon measuring spoon and that will work just fine. So now that we've got all our ingredients, what do we know about clouds? Take a look outside and see if you can see any clouds today. Clouds come in all sorts of different sizes and shapes and even colors. Let's take a look at what some of the different cloud types are. The first one are cirrus clouds. They are thin and wispy, kind of like a horse's tail. And they're really high in the sky. Those are a sign that you are going to have a sunny day today. The next type of clouds are cumulus clouds. Cumulus clouds are also high in the sky. They're light and fluffy, kind of like cotton balls. And they're also a sign that it's going to be a sunny day. The third type of clouds we're going to look at are stratus clouds. They're lower in the sky and they're gray. And they can often cover the whole sky like a blanket. If they're very low in the sky, then they're fog. And we get a lot of that here in San Francisco. So you might have a sunny day today, but if you do have some clouds outside, take a look and observe them. What do you see? What shape are they? Are they thin? Are they thick? Can you predict what your weather will be like today? So how does all, how are clouds made and how does all that water get up in the sky? Well, it's through the water cycle. We have water all around us in rivers and lakes and oceans and even in puddles. The sun warms up the water and it turns the water from a liquid to a gas. This gas is called water vapor. And it weighs less than air so it floats up high into the sky. When it reaches the cold air, the water vapor turns into water droplets. And when water droplets form together, they form a cloud. When the cloud gets too many water droplets and it gets heavy, then it releases rain or snow or hail back down and the water cycle starts over again. So let's see if we can make our own rain clouds and make it rain. So we're going to start with our large vase. And we're going to fill it about two-thirds, three-quarters full with water. And then we're also going to get our three little bowls here ready. We're going to put two tablespoons of water in each of our bowls. And then we're going to add our food coloring. So pick out three different kinds of food coloring. Any color doesn't really matter. And you're going to add about 10 drops to each of your bowls here. We've got some blue, we've got some red. You can experiment with the colors if you want to mix them together and make a purple or something. And then we'll just give those a little stir. And we're just about ready to make our clouds. All right, so in this experiment, the water here is going to represent air. And then we're going to use our shaving cream to make clouds. So give it a good shake. If yours is like mine, it might come out really fast. So be prepared. We're just going to put a layer of shaving cream, clouds on top of our air. And I'm just going to top them down here a little bit. All right, now we are ready to begin our experiment. All right, so let's take our eyedroppers or a quarter teaspoon if you want to use a quarter teaspoon. And we're going to start adding our colored water to our shaving cream. So you can add it one drop at a time. I'm going to go a little faster for the purpose of our experiment here. And keep adding colored water to your clouds. You can try different colors and observe what happens to your clouds. What happens if you put the water in the center of the cloud? What happens if you put water near the edge of the cloud? Predict what will happen as your cloud gets more and more full with the colored water as it gets more saturated. What do you think will happen to your cloud? So keep going. You have to be patient with this. If you're adding it one drop at a time, it can take up to 100 drops before you start seeing it rain. But here you guys can see we're starting to have some rain come out of our clouds. So you can keep going as long as you want. What's happening here is that the cloud is getting saturated with colored water. And when it can't hold water anymore, then it releases the rain. So you can keep experimenting. Add as much colored water as you want. Eventually, all of the colors will combine into a big stormy, brown mess. When you're done, wash your hands. Make sure you clean up your workstation. And thanks for experimenting with me. I'll see you next time. Back to Ileana. Thanks, Kimberly. That was a very soothing experiment. You got to learn about the science of clouds, and you got to see it happen with your own eyes. So for more tips and tricks and resource lists, be sure to check out sfpl.org slash STEM challenge. Keep experimenting and see you next time. Stay STEM-tastic.