Your left hand and right hand are mirror images of each other. There's no way you can position your left hand so that it looks like a right hand. It will only look like a right hand if you look at it in a mirror.
There are molecules like this in chemistry. Molecules that can't be positioned in such a way as to look exactly like their own mirror image. These are called chiral molecules. We talk about them having a handedness because they share this property with our hands. Continue reading →