DIY Valentine using Water Science

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In a previous post my son’s explored semipermeable membranes (coffee filters) by creating beautiful art. While admiring their art, I realized these would make beautiful valentines! All we needed was a change of colors, and addition of some hearts to make an adorable, custom valentine. While I contemplated ways to create the hearts, I remembered another time when we used wax sticks to make some snowflakes appear with watercolor paintballs. Since we were using watercolors for our coffee filter art, I realized we could use the same property of water to create our card!

Kids make their own valentine while exploring several science concepts, including capillary action, semipermeable memberanes, and hydrophilic materials!

DIY Valentine STEAM Activity


STEP 1: Fill the small plastic paint cups with water, then add watercolors from tubes for desired colors. We chose red and purple.

STEP 2: Cut the watercolor paper in half, then fold the cut watercolor paper in half.

Making a card.

STEP 3: Cut the block of clear wax into 1 inch strips.

STEP 4: Draw hearts on one side of the folded watercolor paper. Make sure to go over the shape several times.

Using a wax stick to draw hearts.

STEP 5: Place a coffee filter on top of the watercolor paper. I also placed a wipe-able place mat under the watercolor paper.

Cover the watercolor paper with a coffee filter.

STEP 6: Paint the coffee filter using pipettes and watercolors. Drop one drop of water color at a time, and watch how the paint spreads through the coffee filter.

Exploring capillary action!

My two youngest joined me for the experiment. I have to say, this is one of very few activities I can get them to sit still for all on their own. I loved watching them explore as the watercolors both spread across and through the coffee filter. They also built up their fine motor hand strength by using the pipettes, a skill essential for writing.

STEP 7 (optional): Press down all the bubbles created. My littlest one did this when we created the art pieces before, and did it again for his card. It’s not a must, but does create some really neat designs!

Pressing down the bubbles.

Here’s how the boys’ final paintings turned out!

Our painted coffee filters!

STEP 8: Let the painted coffee filter dry completely.

STEP 9: Once dry, slowly pull the coffee filter away from the water color paper. Notice the beautiful watercolor designs created, and the hearts now visible with watercolors!

Hydrophobic wax exposes our hearts once the paint dried!

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The Science Behind our Valentine

Why couldn’t we see the hearts before we painted the paper, but could after the watercolor was added? The answer lies in how wax reacts to water. Wax is hydrophobic (which literally means fear of water), and repels water whenever water touches it. Watercolors are made of pigment (color) and water. So when the watercolor touches the wax, the wax literally repels, or pushes, the watercolor away!

On the other hand, when watercolor touches the paper, it is absorbed. Watercolor paper is not hydrophobic, but hydrophilic (water loving). When something is hydrophilic, it absorbs water, which is usually clear. But, when mixed with water, the pigment in the paint is also absorbed into the watercolor paper.

My boys are so excited about giving their valentines away! They are absolutely beautiful!

More Valentine’s day STEAM activities

35 Valentine’s Day Science Experiments!
The Science Behind Melting Crayons–A Valentine’s Day Science Experiment