This Playful Science for Preschool course is broken into 8 lessons which each cover a different scientific concept. The lessons incorporate story, movement and experiment for relaxed and fun learning.
These lessons have been tested, by me, on preschoolers at my home school co-op. Every class the students were engaged up until we ran out of time (45 mins). Every class, the students told their parents about the class and I had many positive reviews from the parents.
You can certainly adapt these lessons for a science unit in your classroom, use them piecemeal (maybe you study soap in the fall - germ season - and light in the spring) or use them in the home setting. Many lessons require items you'd find in the home such as baking pans, scales and flashlights.
Feel free to send me any questions you have about the lessons!