Cut an apple into slices leaving the core intact. Give each child several slices.
Have them collect the seeds from their slices. The slices can either be eaten or discarded after the seeds have been collected.
Next provide the children with a plastic sandwich bag and a damp napkin. Have the children place the napkin flat inside their bag. They will then need to place the seeds on top of the napkin and seal the bag. Have the children write their observations of the seed as well as draw or take a picture of the seed.
As time passes and the seed sprouts have the children keep taking notes tracking the growth of the plant. After the seed is large enough then it can be transplanted into a pot with soil.