that this was 5th-grade science. Uhhhh, NOT! When I was in fifth grade, if a teacher had discussed such things, much less showed pictures, she would have been burned as a witch! I use the female "she" as there were no male teachers other than coaches. Granted, they could have discussed both charts in detail and could have shown everyone how to use them, but not very scientifically.

Sucks to get old.