Oceans of Fun: Ocean STEM Activities for Kindergarten

Oceans of Fun: Ocean STEM Activities for Kindergarten

The ocean is a fascinating world and most kindergarten children will freely spill plenty of stories of their oceanic adventures. Teachers can take advantage of this excitement by bringing ocean lessons into the classroom. And what better way of doing it than by using STEM activities.

If you’re on a maiden voyage to find some engaging, educational and of course, fun STEM lessons, I’ve saved you the time of rummaging through hundreds of experiments to bring you five ocean STEM activities for kindergarten that are sure to bring oceans of memorable fun!

Related post: 32 Cool Science Experiments for Kids

Ocean STEM Activities for Kindergarten

Floating in Seawater

Floating egg on a glass of water

Most kids have never wondered if it’s easier to float in saltwater or freshwater. This is a great introductory question to ask the kindergarteners for this experiment, while also introducing the terms “density” and “buoyancy.”


A large glass (tall and clear), lukewarm tap water, an egg (some prefer raw, others prefer hardboiled), salt, teaspoon, and a permanent marker


Fill the glass halfway with tap water and carefully slide in the egg – it will sink to the bottom.


Notice that the egg is sitting at the bottom of the glass. Add 1 teaspoon of salt to the water and stir gently. If the egg slowly begins to float, draw a line on the glass where the bottom of the egg sits in the water.

Continue adding and stirring 1 teaspoon of salt to the water and marking the glass each time until the egg is at the surface of the water. Talk with the children about why they think this happened and how it would affect floating and sinking in the ocean.

Big Shark, Little Shark

STEM activities to compare real sizes of different sharks

Pictures never do a shark’s size any justice. This activity puts into perspective the real sizes of different shark species using the Ocearch Shark Tracker website and some handy classroom materials.


A computer, the Ocearch Shark Tracker website, measuring tape, chalk, and (for added shark-pleasure) these worksheets


Choose two or more sharks species from Ocearch to compare your results. Record the shark’s stats such as species, length, and any other cool facts (one of the provided worksheets has these research questions).


On a large, paved surface, have a child hold the end of the measuring tape to the ground while measuring out the length of one of the sharks. Draw a straight line above the measuring tape with the chalk and write the name of the shark and length on the line. Measure out the other shark lengths above or below each other to compare results.

Build a Microscope for Ocean Specimens

Child at the beach holding different stones and small corals

Microscopes have this magical ability to make you feel like a scientist. Kids (and adults, ahem) love microscopes because they can see their ocean treasures more up close and personal. Before building your own microscope, ask the children to bring in some items they may have picked up from the beach: seashells, seaweed, fish vertebrae, sea glass, etc.


Cling wrap, plastic cups (clear), rubber band, water, and ocean specimens


Cut a small hole in the bottom side of the cup, just big enough to slide the specimen through. Place the cling wrap over the top of the cup and secure it with the rubber band. You’ll want just a little less resistance in the center for the water.


Slide a specimen through the bottom hole into the center of the cup. Pour just a bit of water in the middle of the cling wrap – this acts as the magnifier! Keep the cup steady or sitting on a table so the child can “ooh” and “ahh” over the specimen. Have the child take photos of her specimens or draw what she sees in a nature sketchbook.

Ocean Currents

Ocean current as reference for STEM activity for kids

Any child who has been to the ocean has heard the term ‘current.’ The ocean’s currents are a major part of the movement of the sea, and this activity gives a colorful example of how they work. To see more in-depth descriptions of this experiment and the types of currents, visit Little Bins for Little Hands.


A 9×13” clear pan, cold water, 2 cups boiling water, 1 cup ice cubes, plastic ocean creatures, red and blue food coloring


Fill the container halfway with the cold water, then mix in the blue food coloring and ice cubes. Place the ocean creatures throughout the container.


Mix the red food coloring into the 2 cups of boiling water. Once the water is dark red, slowly start to pour the hot water into the pan. You’ll almost immediately see the currents start to form. Talk about the different types of currents and allow the children to blow on the surface of the water to see what happens.

Magnetic Sandcastle Geometry

Sand paper and scissor for STEM activities

Who doesn’t love to build sandcastles, especially when it focuses on basic geometry and magnetism? Because we’re always trying to find fun ways to teach new concepts, this is a good opportunity to subtly introduce 3 different types of triangles: equilateral, scalene, and isosceles.


A metal cookie tray or small magnetic whiteboard, sheets of sandpaper, and self-adhesive magnetic sheets.


On the back of the sandpaper, draw different-sized shapes such as squares, rectangles, and triangles. Cut out the shapes and pieces of magnetic adhesives. Attach them to the back of each sandpaper shape.


Create specific prompts using geometry terminology such as “Use all scalene triangles on top of the rectangles.” Allow them to engineer their own sandcastles using inquiries such as “How many equilateral triangles can fit inside of one rectangle?” 

You can also have a thin sheet of drawing paper in between the cookie sheet and sandcastle so the child can trace their design and color in their artwork afterward.

Frequently Asked Questions

Can I use preschool and first-grade activities for kindergarten?

Yes! Many preschool STEM activities are helpful for the beginning of the school year to help kindergarten students feel comfortable and confident. Depending on the topic and the simplicity of the lesson, there is plenty of first grade STEM activity suitable for kindergarten age.

What do you teach preschoolers about the ocean?

The most important part of teaching kindergarten or preschool kids about the ocean is to make it relatable for them. You need to draw upon things they can see – water in the bath, sand in the sandbox – and expand their imaginations to consider the vastness of the ocean. At this age it is all about tactile examples and observation of the world around them!

Why are oceans important for kids?

Well, firstly, point out that oceans actually cover more (70%) of the earth’s surface than land! For some kids it can be important to talk about the ocean because if they live in non-coastal areas, they may not have any first-hand experience of oceans and the sea.