Over 3000 searchable STEM (science technology engineer math) activities for kids from preschool to high school - compiled by top science museums in the US. All are FREE, can be accessed on computer or mobile devices via the free app.
PLUS all kinds of other Halloween activities for "littles".
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!
create your own ecosystem- just set them in front of a sunny window so that photosynthesis can happen, setting in motion the cycle of life. The water will evaporate to the top to rain down on the soil, helping the grass to grow and the dead leaves to decompose, which feed the insects. There will be plenty of oxygen from the plants, and the algae that will grow will feed the fish and snails.