What seed would be best to use for a primary school science trick?

My young cousin has come across plants in biology now, and is interested. So, I wouldn’t mind doing a souped up version of the trick of turning celery different colours, and wouldn’t mind a couple of pointers.
The plan is to use a wine bottle or something, and fill it up with water laced with baby bio, and a lot of food colouring. Then, plugging the top with cotton wool, with a seed or few in it. What I’m hoping is that the seeds will germinate, grow happily and then flower in the not too distant future, with the flower being different colour to what was on the packet.
So a couple of questions:
Will it work? It’d be a bit stupid to do it if it wouldn’t :dh:
What plant would work best? I would guess that a white flowering, quick growing plant that doesn’t mind wet roots would be best, but what do you recon?

 

Not sure if this will help or is relevant but commercial growers use carnations to colour via feed as they adapt well...you will have seen them around? as for seeds i suggest experimenting yourself first at home with something quick like mustard & cress or beansprouts...soaking a damp cloth maybe with food colouring for them to grow on. Could be interesting!

 

Would sticking a Flower in something coloured (I think we used Ink at school) do?

http://www.abc.net.au/spark/experiments/s1112186.htm

 

If the whole seed thing isn't likely to work, then Ill do that. Ill have a go at the cress as well. Ta

 

Where do you get cress seed? I went shopping, so went to the biggest Tesco I could find, deliberately to look for cress seed. Mystifyingly I didn't find any? So where to look?

 

The regular lot, Unwins, Suttons, etc., offer it, but they probably work out quite expensive and you may be better off buying from a bulk supplier such as Nickys Nurseries or Moles:

http://www.nickys-nursery.co.uk/seeds/pages/veg2a-cucumber.htm
http://www.molesseeds.co.uk/cgi-bin/ss000002.pl?SS=cress&ACTION.x=0&ACTION.y=0&PR=-1&TB=A&SHOP=

but it will probably come down to Carriage charges, or whether you want anything else at the same time

 

Ta! Ive just remembered theres a BnQ just up the road (moved a few months ago), so Ill try there tomorrow, if not, Ill use them, thanks.