Have you ever played with a spinning top or a toy car that spins around really fast? When something is spinning, it has something called angular momentum. This is like its spin-iness or twistiness.
Now, imagine a beam of light. It might not seem like it's spinning, but it actually is! Light can have what's called angular momentum, too. Instead of twisting like a top, it spins in a way that's more like a corkscrew. It's kind of like when you twist a towel to wring out water.
This spinning light can have different amounts of angular momentum, just like how you can spin a top faster or slower to change its spin-iness. Scientists are interested in studying this because it can have important applications in things like lasers and fiber optics.
But don't worry, it's okay if you don't understand all the details right now. Just remember that light can spin like a corkscrew, and this is called its angular momentum.