You don't learn how to ride a bicycle, multiply three-digit numbers, or play the piano simply by listening to someone else lecture to you about all of the steps involved. To learn the skill personally and make the knowledge your own, you have to practice it. And scientific knowledge is no different from practical skills. If you want your knowledge to actually be “knowledge,” if you want it to be convincing and useful to you, then you have to practice gaining and using the knowledge for yourself. You need to see where it comes from and what you can do with it. To learn science in a deep and personal way, you have to actually do science.
But you don't learn much just by tinkering at random, or by simply noticing something interesting once in a while and then forgetting it. There's a huge world to explore, and putting all of the puzzle pieces together is hard work. “Doing science” is much easier and more productive if you can find other people who know what they are doing. A good teacher or coach can help to guide you as you explore the world, gather the evidence, and put the pieces together. In learning how the world works, a good teacher and a good curriculum can help you condense 3000 years of discovery into a few years of schooling.
This is why we have teachers and schools and textbooks. Education should be like athletic training … athletic training for the mind. In science at least, it should include lots and lots of first-hand evidence (whether in the form of projects and activities that you do yourself, or demonstrations that need to be performed by the teacher), gathered and assembled under the guidance of a special person who can help you to see interesting patterns and to discover the rules by which things are organized.
The following pages present a variety of science activities and lecture demonstrations that I think are useful and valuable components of an organized science curriculum. I used most of them successfully in my own classes when I was a teacher, and I have tried to provide enough discussion so that a homeschool parent, or maybe even a self-learner, can make interesting connections and start to see the patterns in nature and in technology. I've grouped what I have so far into three categories: those meant to support a study of the human body, those meant to support a study of astronomy, and those meant to support a study of “making things” or “physical science.” (The projects are intended to span a range of ages, but many of the astronomy projects are probably more appropriate for slightly older students, and many of the “making things” projects are aimed at somewhat younger students. There is one project on smelting metals, and the rest are mostly aimed at young elementary students.)