Golden Pothos, Sansevieria Trifasciata, Aspidistra(Cast Iron Plant) are a few that should so fine under florescent lighting, with little natural light. How close can you get the plant to the light source? The closer the better, such as on top of a file cabinet.

GH

What direction is the window also. It's odd to me that it makes such a difference but it does. To my eye the sun looks directly overhead so why is north so much shadier than south?

Anyway I'd say get an aspidistra if you can find one because it will grow tall leaves coming directly from the pot, get a pothos to show the kids what vines do (try growing one up and one down to see the difference) and some form of Sans. Yes I know I just stole GH's list, but it's a good list. You'd have three very different looking plants.

If you have enough light try adding a cacti of some sort. Some are fuzzy so they would be kid safe.

Also, a nice tree would work. Perhaps some sort of Ficus depending on the light.

The recommendations so far are probably the best plants for the job, but, if you're wanting other ideas:

I see no problems:

Chlorophytum comosum (spider plant) (educational bonus: can give kids offsets to take home)
Dracaena sanderiana
Dracaena sanderiana 'Lucky Bamboo' (educational bonus: visible root system if grown in water)
Dracaena deremensis 'Warneckii'
Dracaena deremensis 'Janet Craig' (especially the "compacta" variety)
Dracaena fragrans (corn plant)
Sansevieria trifasciata 'Futura' (snake plant)

slight problems:
Aechmea fasciata (urn plant) (would prefer bright light)
Aglaonema spp. (is toxic if chewed)
Araucaria heterophylla (Norfolk Island pine) (would prefer bright light, cool temperatures)
Aspidistra elatior (cast-iron plant) (goes dormant in winter)
Beaucarnea recurvata (ponytail palm) (would prefer bright light)
Chamaedorea elegans (parlor palm) (humidity might be an issue)
Chamaedorea metallica (small fishtail palm) (humidity and light might be issues)
Davallia trichomanoides (rabbit's-foot fern) (they're a little fussy; also go dormant in winter)
Dieffenbachia spp. (is toxic if chewed)
Dracaena marginata (would prefer bright light)
Epipremnum aureum (pothos) (is toxic if chewed)
Ficus benjamina (ficus tree) (can be difficult)
Ficus binnendijkii (long-leaf fig) (said to be difficult, though that's not been my experience)
Ficus elastica (rubber plant) (can be difficult)
Ficus lyrata (fiddle-leaf fig) (can be difficult)
Monstera deliciosa (split-leaf philodendron) (is toxic if chewed)
Philodendron spp. (is toxic if chewed)
Spathiphyllum spp. (peace lily) (is toxic if chewed)
Tillandsia ionantha (air plant) (would prefer bright light)
Zamioculcas zamiifolia (ZZ plant) (is toxic if chewed)

I am reasonably sure I was four years old, almost five, when my grandmother took a jar and filled it with dirt and inserted some bean seed and some corn seed down the side between the soil and the glass so that I could see what was happening.

Both seed sprouted and the roots forced the bean up out of the soil and then it split to reveal leaves. The corn of course just shot up leaves from the seed below the soil.

I was hooked! Sixty six years later I still plant seed and watch plants grow and visit gardening forums where I lurk and kibitz.

Mr Sub, that's a great idea about the spider plant..not only will the children learn, but rewarded by offshoots to boot..Great idea..Toni

When I first taught my children about plants I started with plants that could be eaten, then went to the plants that couldn't.

Why not some herbs? They are easy to grow, smell good, and taste good also, none of the plants listed can be eaten. They also grow good under lights. Mints and lemon balm come to mind, parsley, chives and basil are also good choices.

Now my kids are better at growing lithops and other mesembs than I could ever be!

Sweet Basil! Grows fast and when they rub the leaves and sniff their hand it'll smell great! It's like magic!