What a great project! Perhaps a Blue Lake would be my choice for this. When they are ready, the children could pick them and eat them raw...tender, crisp, delicious.

Brighty, what a wonderful learning project for the children. I would suggest planting several types of a few each. Green Beans, Limas, etc and different colors.

Good luck,
Luther

Kids love purple, and are impressed by things that are worth bragging about. I would suggest "Chinese Red Noodle" yardlong beans... or for that matter, any yardlong bean. The pods enlarge & get even longer if allowed to get ripe, and look kind of like snakes at that stage... the kids would probably have a lot of fun with them.

A yellow pole bean like "Goldmarie" would probably be a hit too, or one of the purple Romano-type pole beans. Even one of the green-podded beans like "Fortex" would be interesting, it has pods up to 11" long. Both "Goldmarie" and "Fortex" are good eaten raw, especially when fresh picked.

Thank you all so much! What wonderful ideas. They are going to have fun discovering all the different colors and sizes and eating them right off of the pole! I'm going to have fun too! :)

Brighty

IMO, the best pole bean for me and mine bar none is Louisiana Purple Pod. I've grown it is my exclusive every year pole "green" bean for over thirty years now. Productive to beat the band, disease and pest resistant and only the worst of droughts will faze it with little to no summer slump when the heat hits. The only downside is it's like okra must be picked on schedule every third day, it's that productive.
Careful of limas and kids. Raw lima beans contain linamarin which can make people ill if raw limas are eaten in large quantities, cooking destroys this compound. It's not really an issue though as I've nibbled on raw beans all my life and my four year old treats them like candy but it is there and published in the literature so use caution. Also the pod of limas is inedilbe with a stiff point that could cause problems if a child were to eat a whole pod.
If you want a really good heirloom (Louisiana Purple is also an heirloom) I like the Rattlesnake for good old fashioned bean flavor (stronger and meatier) as this was what I grew up on before switching to my purple beans. It's a bean that is about as tough as they come just not as prolific as the purple.

Last year I did a bean teepee for my own preschool aged son. we planted purple podded pole beans and scarlet runners. They are different species, so they can grow side by side without crossing, so you can safely save seed from both. Both can be eaten raw off the vine (and with my 3yo son chomping away, we never actually got any into the house to cook!). Plus the flowers on the scarlet runners are GORGEOUS, and when you let them dry up to save seed for the following year, the seeds on them are large and really beautiful (black mottled with hot pink). I'll be doing the same again this year for my son's preschool class garden at school. If I werent expanding my plantings to cover our home and his school I'd offer to send you some saved seed to use, but I dont think I have enough. But I got both varieties from Seed savers exchange online store