I love to have a theme day that is easy, low prep but has a big impact.  This one definitely delivers – the kids will get a treat, do some art and get to see some pretty cool science in action – and you will save your sanity because these are fun and easy to pull off!  We’re going to have some STEAM powered fun by blending science concepts with a winter theme! We will explore principles like solubility, hydrophobicity, and chemical reactions with engaging hands on discovery. 

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What is Hydrophobic vs Hydrophilic?

First things first, you might be wondering… what does hydrophobic and hydrophilic mean? Let’s explain it in a really easy to understand way for kids.

Imagine you have two friends. One friend loves water and always wants to go swimming or play in the rain. This friend is like “hydrophilic” a word that means “water-loving.” Hydrophilic things enjoy being around water and mix well with it.

The other friend doesn’t like getting wet at all and stays away from water whenever possible. As soon as the rain starts they want to get inside, and on a trip to the beach they would rather stay on the sand, then splash in the waves. This friend is like “hydrophobic,” which means “water-fearing.” Hydrophobic things avoid water and don’t mix with it.

So, hydrophilic things mix well with water, like sugar dissolving in tea, and hydrophobic things don’t mix with water, like oil floating on top of water.

All of these easy experiments explore the concept of hydrophobic (water repelling) and hydrophilic (water loving) substances.  

Cinnamon Hot Cocoa Experiment

Objective

Our objective with this lesson is to teach students about solubility by observing how hot cocoa powder dissolves in water, while cinnamon, which is hydrophobic, floats on top. 

Supplies

Hot water or warm milk
Hot cocoa mix (store-bought or homemade)
Ground cinnamon
Clear plastic or glass cups
Spoons

Optional: Marshmallows for extra holiday fun!

Directions

Start by adding 1-2 tablespoons cocoa mix to each cup.

Sprinkle some cinnamon on the cocoa powder.  

Now carefully fill each student’s cup with hot water or warm milk and have them stir gently. 

Observe

Have a class discussion about what they see.  The hot cocoa mix should dissolve into the liquid, creating a smooth drink while they will begin to see the cinnamon separate and rise to the top.

Explain that cinnamon is hydrophobic, meaning it repels water. It will likely clump and rise to the top, forming small islands on the surface. Here is a picture of a little island of cinnamon forming in our hot chocolate experiment.

Discuss

Talk with the students about how some materials dissolve in liquids while others do not. They can also experiment with more or less cinnamon to see if it ever mixes in. Or try different techniques to see if they can make the cinnamon mix in.

Science Connection

This activity visually demonstrates the difference between hydrophilic (water-loving) substances, like cocoa mix, and hydrophobic (water-repelling) substances, like cinnamon. It’s a tasty way to introduce solubility and the concept of polar and nonpolar molecules.  Now add some marshmallows and enjoy a tasty treat. 

Hydrophobic Pictures

Objective

Students will create some festive artwork while learning about hydrophobic materials by using wax and watercolor to make a holiday project with a snow or secret message effect.

Supplies

White construction or watercolor paper
White crayons 
Watercolor paints (blue or green for a wintery sky)
Paintbrushes
Cups of water
Paper towels

Directions

STEP 1 Draw with Wax

Have students use white crayons to draw Christmas trees, snowpeople, merry messages, or any wintery scene they like on the paper. Encourage them to press down hard so the wax stands out.

STEP 2 Add Watercolor

Dip a paintbrush in water, then into the watercolor paint. Ask students to paint over the areas where they drew their wax designs.

STEP 3 Observe the Magic!

The wax will resist the watercolor paint, allowing the designs to stay white, creating a snow effect on the picture of trees, or revealing secret images or messages.

Science Connection

Wax is hydrophobic, which means it repels water. When the students paint over their designs, the watercolor flows around the wax but cannot stick to it, making the wax designs stand out. This is a simple way to explore hydrophobicity through art!

Snowstorm in a Jar

Objective

Using a simple chemical reaction, students will observe how a mix of water, oil, paint, and glitter can create a “snowstorm” effect in a jar.

Supplies

Clear glass jars or plastic containers with lids (one per student)
Baby oil
Water
White paint
Glitter (silver or white for a snow effect)
Alka-Seltzer tablets
Optional: Blue food coloring for a wintry hue

Directions

First we need to add the baby oil.  Fill the Jar about three-quarters of the way with baby oil.

Add some white latex paint and some glitter to water you could also add a drop or two of blue food coloring if you would like it to look a little frosty – you’ll want enough to fill the jar the rest of the way with just a little space at the top. 

Pour the water mixture into the jar with the oil.  You will see it pour right through the oil – take a moment to explain that oil and water don’t mix, so if you watch carefully you will see the water will sink to the bottom.

Let the students observe the layers of oil and water, noting how they stay separate.

Create the Snowstorm

Now it is time for the magic! Break an Alka-Seltzer tablet into pieces and drop one piece into each jar. The tablet will react with the water, creating carbon dioxide gas that will make the water and glitter swirl in the oil, resembling a snowstorm.

Do it again and again! Once the reaction slows, students can add another piece of the tablet to keep the snowstorm going.

Science Connection

This experiment uses the fact that oil and water don’t mix and the chemical reaction between Alka-Seltzer and water, which produces bubbles of carbon dioxide gas. As the bubbles rise, they carry water droplets up into the oil, creating a “snowstorm” effect. This activity is a fun way to introduce chemical reactions and density differences, plus wrap up the hydrophobic conversation with the kids – because oil will not mix with water and will repel it when they come in contact. 

For a more in depth experiment with Snowstorm in a Jar – check out this article! https://www.steampoweredfamily.com/snowstorm-in-a-jar/

These holiday-themed STEM activities are designed to engage students with hands-on learning and seasonal fun. Through making hot cocoa, painting wax-resist art, and creating snowstorms in jars, students can explore scientific principles in an exciting, memorable way. Give these a try in your classroom, and watch students’ love for science grow!  If you’re looking for another STEM experiment the kids will love check out Build a Gnome Snow Globe