🌋 Underwater Volcano Science Experiment for Kids

This simple underwater volcano experiment allows children to observe an undersea volcano, learn about density, and go through the scientific method. This simple science experiment for kids is good for preschool, pre-k, kindergarten, first grade, and 2nd graders too.

Underwater Volcano

I love using simple science experiments to help kids discover the wonder of science and learn to think critically about the world around them. In this underwater volcano demonstration, children will get to see not only what a volcano in the ocean might look like, but explore a density experiment for kids too. All you need for this easy science experiment are a few common household items. Whether you are a parent, teacher, or homeschooler – you will love this science project for preschoolers, kindergartners, grade 1, and grade 2 students.

Underwater Volcano Experiment

This experiment has a cool WOW moment with simple household items you already have in your kitchen:

large TALL clear container
film canister
a heavy object that will weigh down the smaller container (we’ve used small rocks and coins)
water
red food coloring

Density Experiment for Kids

Start by filling the large container with cold water. The colder the better to make a more dramatic contrast between the two temperatures.

Now prepare your smaller container by putting a rock or two in the bottom of the small container.Add a couple of drops of food coloring in the small container – this allows us to see the movement of the hot water in the cold water. Finally, fill the small container with very hot water. The hot water should cause the food coloring to mix without stirring, but feel free to stir with a chopstick to stif if yours isn’t.

Hot and Cold Water Experiment

While keeping the small, red hot water container upright, gently release the small container in the large container. Observe as the red water erupt from the small container like a volcano!

Easy science experiments

Have children make observations. What is happening?

Kindergarten science experiments

The food coloring is now staritng to evenly distribute. WHY?

HINT: The hot water and cold water are making warm water. Once all the water is the same tempearture the food coloring will have blended completely.

Science Experiment for Kids

So other than looking cool, what are you learning? Well kids are learning a couple things in this simple science experiment:

Density – hot water is less dense than cold water. As a result, the warmer water will rise to the top, while the cold water sinks to the bottom. We exagerated the effect to produce the underwater volcano demonstartion by placing a rock to quickly sink the small container. As a result, the hot water shoots up and looks like a volcano erupting.

The Scientific Method – help kids learn how to think critically even from a young age.
- Ask a Questions – What will happen if we put hot water inside cold water?
- Form a hypothesis – I think the hot water will spread into the cold water.
- Try an Experiment – Do the experiment
- Observe and record – The red, hot water burst straight up out of the container
- Draw conclusions – Something about the hot water caused it to move out of the jar into the cold water. My findings support my hypothesis.
- Ask More Questions – there were only 2 differences: temperature and color. If you change the color of the hot water will you still have the same results?
- Try a 2nd Experiment – Do the Experiment and see if your Conclusion holds.
Hot and cold molecules – Teach what molecules are and why the hot and cold molecules are different.
Following directions – Following directions is an important skill for students to learn. If you skip directions of adding a rock, the temperature of the water, or adding food coloring, the experiment would be a bust.

See a real underwater volcano errupt.

Ocean Activities for Kids

Looking for more ocean activities for kids? You will love these clever, free resources and ideas:

Ocean Color by Number Worksheets
Build an Ocean Scene with this fun Fractions Activity
Ocean Simple Coloring Pages
Ocean Worksheets for Learning Numbers 1-10
Pearl Color Matching activity
Try this Watercolor and Crayon Ocean Craft
Ocean Printable Count & Trace for prek / k
Cupcake Liner Octopus Craft
Tons of ideas for a weeks worth of fun learning with an Ocean Theme
Octopus Color Matching Craft
50 Amazing Ocean Crafts for Kids
HUGE Ocean Animals Unit

Summer Fun

Looking for more outdoor activities for kids and things to do in the summer? Your toddler, preschool, pre k, kindergarten, and elementary age kids will love these fun ideas to keep them busy all summer long:

Marshmallow Shooters – go over 30 feet!
Lemon Volcano is a fun Summer Experiment for kids of all ages
Ice Cream Volcano – fun ice cream activity for summer!
2 ingredient Easy Slime Recipe
How to Make a Simple Newton’s Cradle Science Experiment
Super Simple Sand Slime
EPIC Mentos and Soda Experiment
How to Make a Lava Lamp – it’s super EASY!
DIY Water Xylophone Activity – Sound Science Experiment for Kids
Kids will no nuts over this simple Pop Rock Experiment
Easy Button Crafts for Kids
Handprint Strawberry Craft for Summer
Grow Your Own Crystals
Water Balloon Experiment – exploring densit with an EPIC summer activity for kids
Amazing Bubble Painting
Mind Blowing Color Changing Playdough
Disolving Seashell Activities – a Summer Science Experiment