Activity

Cheek cells

Summary
Look at cheek cells stained with methylene blue, or iodine, under the transmission microscope.
Science content
Biology: Features, Adaptations of Living Things (K, 1, 3, 7)
Biology: Sensing, Organ Systems (4, 5, 6)
Materials
  • non-pointy toothpick for each student
  • glass slide and cover slip for each student
  • methylene blue, 1% (0.5% in some fish medicines works great). If not available use tincture of iodine, from the drug store
  • microscope, ideally with a 40X lens
Procedure

Students add a drop of methylene blue (or iodine to a slide).
Students scrape cheek cells from the inside of their cheeks with a toothpick, then wriggle them off in the drop on the glass slide.
Drop on a cover slip.
Look at the cheek cells under low power to start to find the cells.
Then increase the power, keeping a good-looking cell in the centre when moving up to the highest power.
Look for the nucleus in the centre of the cell.
With methylene blue, other cell organelles are also visible, and sometimes bacteria (dark blue spots outside the cheek cells).

Notes

Primary students, and many intermediates, need a strong teacher presence around the microscope.

Grades taught
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6
Gr 7
Teaching site
Gordon Elementary
Gordon Elementary Science Club
Tyee Elementary