Milk. It's that white stuff that's sold in cartons. Processed in a factory, and then sent over to supermarket shelves, right?
The National Farmers' Union (NFU) in Wales is so fed up with the widespread belief among schoolchildren that milk is manufactured on the factory floor, alongside fizzy drinks and orange squash, that it has taken decisive action.
In an effort to show pupils just how milk looks in its original packaging, John Lougher, Glamorgan co-chair of the NFU, has begun to visit south Wales schools, accompanied by a three-year-old cow.
He believes that the farmers' beef is genuine: "Lots of children think that milk is just another drink, like pop.
"Even teachers don't realise that it's a purely natural product. We're telling them to drink this stuff but they don't know where it comes from."
Tanglwyst Rubyton Amy, a prize-winning pedigree Holstein, accompanies Mr Lougher into playgrounds in Cardiff and the Vale of Glamorgan.
As curious pupils look on, the placidly ruminating bovine is milked using a portable machine. Mr Lougher then produces a small vat of pasteurised milk, retrieved from Amy earlier, and pours each pupil a small sample to try.
Sue Jordan, whose pupils at St Brides Major primary, in the Vale of Glamorgan, received a visit from Amy recently, believes that it is an opportunity, if you'll excuse the pun, to be milked for all it is worth.
"Unless they have followed wildlife programmes, most children don't know much about cows," she said. "Bringing one into familiar surroundings means that it is less scary for them."
Nine-year-old Amy Taylor agrees. She said: "The cow was less aggressive than I'd expected. She was gentle and kind and liked having children around her. She probably likes being in school more than I do."
Her Year 5 classmate, Molly Llewellyn, is equally enthusiastic about seeing farm animals in their school. "Now I know how milk is made," she said. "You squeeze the udders and clean the bad bits off before you drink it.
"I'd like them to bring other animals in. It helps us to learn about their daily life. Maybe we can see an elephant or a giraffe next."