> Uhhh.... Having done some research with adults and with 15 year-olds on > concepts of infinity, I hope folks are recognizing that these are very > non-trivial ideas. For example, about two different lengths of segments > etc.
Amen to all of that. I agree that 5th grade is not the place to be talking much about infinity. as i had said, i've worked with these kids for many years, and have touched on the subject of infinity only rarely. yet there are many topics that will excite them and get them thinking mathematically.