Make it Rain in a Jar: A Simple STEM Experiment for Kids

Looking for a fun and easy way to teach kids about clouds and rain? This hands-on STEM experiment uses just a few household items and helps little ones understand how rain is made—right before their eyes!

What You’ll Need:

    •    A clear container

    •    A mini strainer

    •    Cotton balls

    •    Water (add blue food dye for even more fun!)

    •    A spoon, little cup or dropper

Instructions:

    1.    Place the strainer the top of the clear container.

    2.    Arrange cotton balls on top of the strainer so they cover the opening.

    3.    Using a spoon or dropper, slowly pour water onto the cotton balls.

    4.    Watch closely! After a few moments, you’ll see drops of water begin to fall through the mesh into the jar—just like rain.

What’s Happening?

This simple setup mimics how clouds and rain work in nature. The cotton balls represent clouds. As you add water to them, they become heavier—just like real clouds do when they collect moisture from the air. Once they’re full and can’t hold any more, the water starts to drip through—just like rain falling from saturated clouds.

The Science Behind It:

In nature, clouds form when water vapor rises into the air and cools, turning into tiny droplets that stick to dust particles. These droplets cluster together to form clouds. As more and more moisture gathers, the droplets grow heavier until gravity pulls them down as rain. This experiment visually shows that process in a way children can see and understand.

Why It’s Great for STEM Learning:

    •    Science: Kids learn about the water cycle and how clouds produce rain.

    •    Technology & Engineering: Using materials to create a model encourages design thinking.

    •    Math: Children can count the drops, measure how much water it takes before it rains, or time how long it takes.

Tips for Exploring Further:

    •    Try warm vs. cold water to see if the “rain” falls faster or slower.

    •    Add food coloring to the water to make the rain more visible.

    •    Ask questions like: What do you think will happen if we add more cotton balls? or How much water can one cotton ball hold?

This activity is perfect for preschoolers and early primary kids and is a great addition to any weather-themed learning or science table. Plus, it’s a lovely way to spark curiosity and conversation about the world around them.