Kaon

A Kaon is a teeny tiny particle that is smaller than an atom. It's kind of like a particle that likes to change clothes a lot, because it comes in two different types or "flavors" called K+ and K-.

Now, inside of every Kaon there are even teenier tinier things called quarks. Quarks are kind of like building blocks that make up everything in the universe. In a Kaon, there are one "up" quark and one "anti-strange" quark (for K+) or one "down" quark and one "strange" quark (for K-).

When Kaons are born (made), they are usually one flavor, either K+ or K-. But as they travel or hang out they can suddenly decide to change flavors! This is called "Kaon oscillation". It's like if you had a blue crayon and then it became a red crayon, and then it turned back into a blue crayon again (!).

Scientists really like studying Kaons because they can tell us a lot about how the universe works. For example, Kaon pairs can be created when high-energy particles smash into each other, and by measuring how often the pairs change flavors, we can learn about things such as physics beyond the Standard Model and what's called "CP violation". Pretty cool, huh?