Ancient Egyptian sculptors wanted to show what people were really like inside, not just what they looked like on the outside. What if you drew two portraits of yourself - what you really look like on the outside, and what you are really like - your true self? Would the two pictures be the same, or different? What if you drew your classmate instead of drawing yourself? How could you use drawing to show what someone's real self was like?
Would your real self be bigger, or smaller, than you look? Stronger, or weaker? Sweeter, or tougher? Would your real self wear different clothes? Have a different hairstyle?
Bibliography and further reading about ancient Egyptian sculpture:
Eyewitness: Ancient Egypt, by George Hart. Easy reading.
Ancient Egyptian Art, by Susie Hodge (1998). Shows kids how Egyptian art relates to Egyptian religion and culture.
Hands-On Ancient People, Volume 1: Art Activities about Mesopotamia, Egypt, and Islam, by Yvonne Merrill and Mary Simpson. Art projects for kids, though the directions are really aimed at teachers or parents.
The Art and Architecture of Ancient Egypt (Yale University Press Pelican History of Art), by William Stevenson Smith and William Kelly Simpson (revised edition 1999). The standard for college courses.
Egyptian Art, by Cyril Aldred (1985). Another standard.