Okay kiddo, so planar chirality is when something looks the same but is actually different. Let's say you have two paper cutouts of a butterfly that are the exact same shape and size, but one is facing left and the other is facing right. Even though they look the same, they are actually different - this is planar chirality!
This can happen in molecules too. Imagine you have a molecule called limonene. It's a type of oil that smells like lemons. Limonene has a special kind of planar chirality. It has two mirror images that look the same, but are actually different.
It's like if you held up a mirror to your face - your reflection looks just like you, but is actually different because it's facing the opposite direction. Limonene has a similar kind of reflection symmetry in its molecular structure.
Scientists study planar chirality because it can affect how molecules behave and interact with other molecules. Understanding planar chirality can help us design better drugs or create more efficient chemical reactions. So while it may seem like a small and simple concept, it's actually pretty important!