DIY Growing Caterpillars

Materials you'll need

• Paper towels
• Scissors
• Washable markers (a few colors, plus black)
• Pencil
• Glue stick or liquid glue
• Plate
• Water

 

Step-by-step tutorial

Step 1: With an adult's help, cut a paper towel in half.

Step 2: Using washable markers, draw colorful lines and patterns across one half of the paper towel.

Step 3: Starting from one edge, roll the paper towel tightly around a pencil to form a tube.

Step 4: Add a small dab of glue to the loose end and press it down to seal the roll.

Step 5: Scrunch the tube together along the pencil, squeezing it into an accordion shape.

Step 6: Carefully slide the scrunched tube off the pencil. This is your caterpillar's body.

Step 7: Use a black marker to color one end solid black for the head, then add small dots along the body for its markings.

Step 8: Set your caterpillar on a plate and slowly pour water over it. 

Learn more

This colorful transformation happens thanks to capillary action — the same force that lets a paper towel soak up a spill. Paper towels are made of tiny fibers with narrow gaps between them, and water can travel through those gaps in any direction, even upward against gravity, without needing to be pushed. When you pour water onto your caterpillar, it spreads through those tiny gaps and carries the marker ink along with it, blurring your neat lines into soft, blooming patterns. It's the same trick that lets a plant pull water from its roots all the way up to its leaves.