I have been thinking that most of the basic concepts of geology can be explained in terms of cake:
If you take a crumb from the cake and look at it under a microscope, that's petrology.
If you investigate the icing, that's surficial geology.
If you examine the layers of the cake, that's stratigraphy.
If you slice the cake, that's tectonics.
If you put the cake on a plate and slide it around, that's plate tectonics.
I suppose that I could extend the analogy further by saying that if you study the dead animals that you find in the cake, that's paleontology, but no one wants to find dead animals in a cake.