Ouch! If you've ever brushed against a stinging nettle, you've met these cells. Each stinging hair is one single cell shaped like a tiny needle.
Drag to turn it around. Use the buttons to zoom in and try things from the lessons.
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Stinging nettle plants are covered in tiny hairs. Each stinging hair is a single cell, long and thin like a needle, sitting on a little bump of other cells.
Its tip is a tiny glassy ball. The walls near the tip are hard and brittle, like thin glass, so they break easily.
Inside, the hair is filled with liquid that contains stinging chemicals.
One stinging hair is a single cell, but it is long enough to see with a magnifying glass.
When skin brushes the hair, the glassy tip snaps off. That leaves a sharp, slanted point, a bit like a doctor's needle. The point pokes into the skin, and the stinging liquid squirts in.
That makes the skin itch, burn, and get little bumps for a while. It's the plant's way of saying "don't eat me!"
Press Snap the tip on the 3D model, then Squirt the sting.
Lots of plants have hairs that don't sting at all. These soft, fuzzy hairs can shade a leaf from strong sun, help keep it from drying out, and make it hard for small insects to walk and munch.
Gently stroke a fuzzy leaf, like a lamb's ear plant or a tomato leaf, and look at it with a magnifying glass. Never touch a stinging nettle, and wash your hands after touching plants.
By Science and Plants for Schools. Good for older kids.
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