Speaker 1: Welcome to brain stuff front house, stuff works dot Com
Speaker 1: where smart happens. Hi Am Marshall Brain with today's question,
Speaker 1: how do scratch and sniff stickers work? Scratch and sniff
Speaker 1: stickers are one of those novelty technologies that sound like
Speaker 1: such a great idea, but they've never really caught on
Speaker 1: except in children's books and the occasional perfume strip in
Speaker 1: a magazine. But if you do have kids, you probably
Speaker 1: have a scratching sniff book around the house, and even
Speaker 1: if the book is twenty years old, it still works.
Speaker 1: The reason the stickers last so long is because of
Speaker 1: the micro encapsulation technology used to create them. The basic
Speaker 1: idea behind scratch and sniff is to take the aroma
Speaker 1: generating chemical and encapsulate it in a gelatin or plastic sphere,
Speaker 1: and these spheres are incredibly small, on the order of
Speaker 1: a few microns in diameter. When you scratch the sticker,
Speaker 1: you rupture some of these spheres and release the smell.
Speaker 1: The smell is essentially held in millions of tiny bottles,
Speaker 1: and you break a few of those bottles every time
Speaker 1: you scratch the sticker. The tiny bottles preserve the fragrance
Speaker 1: for years. It turns out that the micro encapsulation technology
Speaker 1: used in scratch and sniff was first developed to create
Speaker 1: carbon less copy paper. The top sheet of the paper
Speaker 1: is coated with the micro capsules containing a colorless ink.
Speaker 1: When you write on the paper, it breaks the capsules
Speaker 1: and releases that inc The ink mixes with a developer
Speaker 1: chemical on the next sheet of paper, and it creates
Speaker 1: a dark color. It's carbon less carbon papers. For more
Speaker 1: on this and thousands of other topics, is it hastaff
Speaker 1: works dot com.