If you work with young children in any setting--home, school, or childcare-- you need to know the wonderful benefits of science. Maybe you get the shudders when you think of science, and the thought of trying to teach it to others gives you chills. Do you remember physics or chemistry from high school? Even if you loved science then, you may not understand how to teach preschoolers about it.
I taught preschool for several years through graduate school. One of my favorite graduate classes was science education for young children. I went into that class with outdated ideas about how to teach science. In my defense, though, almost everyone in education had wrong ideas, so I was just teaching the way I'd been taught. What I learned in that class changed my thinking drastically, and science became one of my favorite vehicles for teaching preschoolers.
The text for my class was called Physical Knowledge in Preschool Education (Kamii and DeVries, Prentice Hall, 1978). Granted, most textbooks tend to be boring, but this one was awesome. I learned that preschoolers are natural scientists. They experiment, observe, and with a little help, make predictions. I learned that the best science activities for young children possess four characteristics: 1) The child must be able to produce movement by his own action, 2) the child must be able to vary his action, 3) the reaction of the object must be observable, and 4) the reaction of the object must be immediate.
Let me elaborate on these by comparing a 'traditional' science activity with one that better meets the abilities of young children. In many preschool classrooms you'll see a teacher helping children fill a cup with soil, plant a lima bean seed, put some water in the cup, then set it in a window to wait. This might be a good way to introduce life science to a middle-schooler but not to a young child.
Let's apply my four-part test to it: Is the child producing movement by his own action? No, this activity is not about movement, and in fact, movement ruins the outcome. Is the child able to vary his action? No, the child has to follow a script, and any change is likely destructive. Is the reaction observable? Only marginally yes, because the reaction being studied happens over many days. Is the reaction immediate? Absolutely not.
Compare this to the following 'play' activity: Collect the following items: a kleenex, a round tinker toy, a popsicle stick, straws, an empty orange juice can, an empty coffee can, some marbles, two or three small blocks. Clear some floor space and ask your child "Can you find something that you can blow across the floor?" (I have done this both with and without a straw to blow through. You might wait and see if your child comes up with this idea before giving them a straw.) All four test characteristics come into play.
You'll see your child engage in experimentation, comparison, and classification; all with a liberal dose of fun. Some of the items will move, so children will innately categorize the items as 'blowable or not blowable'. Both science and math result, and often, rich language experiences too.
If you work with your own child at home, or you work in a classroom with kids, it helps to think about science this way. You may not wind up with lima beans, but your child will build a great foundation for asking questions, making predictions, trying out new strategies, and developing a bank of knowledge about how the world works.