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