Dandelion Magic Trick- Make Stems Curl in Seconds

Love or loathe them, dandelions are a common feature in spring. One day, there are just a few, then suddenly they seem to be everywhere. A combination of day length and increasing temperatures leads to a massive synchronised bloom in April or May. It might be tempting to get rid of the pesky weeds, but leave them if you can, as they are an important early source of nectar for bees and butterflies.

Dandelions are also great for science experiments! This simple dandelion curling STEM challenge is a fantastic demonstration of osmosis and a fun science trick.

Dandelion Curling STEM Challenge

You'll need

A dandelion with a long, thick stem.

Scissors

Glass

Water

Instructions

Carefully use the scissors to cut the dandelion stem in half.

Place the dandelion in a glass of water and watch as the stem strips curl tightly into ringlets.

Extension task

Try it again, but this time cut the stem into 4 separate strips.

Try using warmer and colder water to see if the speed of the curling changes.

Why do dandelion stems curl?

The inside of a dandelion stem contains thin-walled parenchyma cells, which absorb water quickly through a process called osmosis. They expand and become turgid as they absorb water.

The outside of the stem is waxy and rigid, it can't easily expand and doesn't absorb water.

As the inner cells stretch and swell, the outside of the stem is forced to curve, resulting in springy curls.