Field Journal (Draw and write about something you learned this week.) Length: 1st grade just a few words; 2nd grade 1-2 sentences; 3rd grade and up 3-5 sentences.
Moms: Using a hot iron (mine was on "cotton") reveal your secret message from your child. :)--you could also try a hot lightbulb.
(This works because the acetic acid in the vinegar neutralizes the calcium carbonate in the eggshell, releasing carbon dioxide and weakening the shell.)