I would say with my older children I have adapted a very eclectic style over the last several years and it works for us. I do enforce certain subjects that like it or not, you have to learn (fractions) but I allow for wiggle room if there is a subject that the children passionately want to learn about I am not so rigid as to say we cannot look into it because we have other studies. A perfect example of this, just yesterday one of my children had lots of questions about clouds and which ones did what and why some days there were great big puffy ones and other days they were wispy. We opted to just take a day off her regular science curriculum and now, after research, her curiosity is satisfied and she has new names for the clouds!
I am finding that with my youngest two boys I am really favoring an "unschooling" approach to pre-school. Don't get me wrong we are still learning letters, numbers, shapes, etc. but we are following the interests of the boys to do so. I am usually not a huge fan of the idea of un-schooling as at its core it is just allowing a child to only learn what they are interested in, my fear? What if they are never interested in multiplication tables, learning to read, history? Therefore I feel this approach is working for my younger boys but when they get older we will likely move more towards the approach that has worked for my other three children.
So, what does this "un-schooling" look like for pre-school? It is piquing your child's interest so that they desire to learn and then following that up with good solid information. Case in point, we have been enjoying some unseasonably warm weather this December so it necessitated a walk outdoors for the boys who frankly needed some fresh air and a change of scenery. One of the first things that caught my eye was an incredibly long mole hill trail that not only sectioned my property but continued for almost the length of a football field (that is one industrious little guy!) It dawned on me that my boys probably didn't know much about moles so we began by walking the length of the mole trail and talking about what caused that protruding dirt, can you see it here? It looks like it ends but I assure you it goes on and on and on some more!
Keep in mind too that you don't have to live on a farm to do this kind of learning, there are opportunities literally EVERYWHERE! Just think, you may have flowers in your yard so you learn about why they give off that yellow stuff on your fingers and watch as bees come by, you may decide to let your child play in a sink full of water and see what objects can float and what can sink, you may listen to different kinds of music and talk about instruments, the possibilities are literally endless.
Think about it like this, as an adult when you want to learn something new, what do you do? You seek out information. It may be in the form of books, how to videos, magazine articles, you get the picture. By teaching children at a young age that they have the power to learn about the world around them and all they have to do is seek the information, you are setting the stage for a lifetime of learning!