This short clip shows electron micrograph images of a human egg. It explains that a human egg is barely visible to the human eye and could easily fit onto the tip of a pin.
This clip could be used to demonstrate how small human cells are. After showing this clip, the teacher could explain that the human egg cell is the largest cell in terms of volume in the human body, and the sperm cell is the smallest. This could lead into a discussion on why these gametes are sized in this way.