Look at cheek cells stained with methylene blue, or iodine, under the transmission microscope.
Science content (2016 curriculum):
Biology: Features, Adaptations of Living Things (K, 1, 3, 7)
Biology: Sensing, Organ Systems (4, 5, 6)
Science topic (2005 curriculum connection):
Life Science: Animal Growth and Changes (grade 2)
Life Science: Human Body (grade 5)