Over 3000 searchable STEM (Science, Technology, Engineering and Math) activities for kids - compiled by top science museums in the US. All are FREE, can be accessed on computer or mobile devices via the free app.
How Do Leaves Breathe? A Simple Science Experiment for Kids
Ed Dancing raisins activities. Lots of fun experiments. I have done this experiment, and seen the entire class become silent out of curiosity. It is a great engagement piece for a lesson, and it can be hands on if you ask for volunteers!