Why Does Looking at the Sun Make Some People Sneeze?

Have you ever walked outside on a bright sunny day and suddenly sneezed... with no dust, no pepper, no cat fluff anywhere? Just sunshine and a sneeze? There's a real science reason behind it.

Dr Matt Agnew investigates the sun sneeze mystery. What even is a sneeze? Why does bright light trigger one for some people? And why does it run in families?

What you'll learn:

Sneezing is your body's nose cleaning button... a blast of air that clears anything annoying from your mucous membraneWhen bright sunlight hits your eyes, your brain urgently signals blink and squintFor about 1 in 4 people, the blink button and the sneeze button sit really close together in the brain... so pressing one accidentally bumps the otherScientists call this ACHOO Syndrome... short for Autosomal Dominant Compelling Helio-Ophthalmic OutburstSun sneezing is linked to your genes, which means it can run in familiesSun sneezes won't hurt you... but stop before the sneeze hits if you're on a bike or crossing the road

Key Science Ideas:

Mucous membrane: The sticky lining inside your nose that catches dust, germs and anything annoyingOptic nerve: The nerve that carries signals from your eyes to your brainACHOO Syndrome: The scientific name for sun sneezing... and yes, the acronym was absolutely intentionalGenes: The instructions inside your body that decide things like eye colour, height, and apparently whether sunshine makes you sneezeReflex: An automatic body response your brain triggers without you choosing it

Fun Experiment: The Family Sun Sneeze Survey Ask everyone in your family whether they sneeze when they look at bright light. Try a torch in a dark room if the sun isn't cooperating. Keep track of who does and who doesn't. If sun sneezing runs in your family, you'll start to see a pattern... and you'll have just conducted your first genetics experiment at the kitchen table.

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