[Plant-biology] Growing seed / plant in only fresh water without draining question tia sal2

[ratulloch from gmail.com]

Greetings All

I'm doing a little experiment with growing plants and the effects vary
magnetic fields on them.
I would like to grow plants in a test tube and measure there growth.
What types of seeds would be the best to use that's fast growing and
will grow in water.  I know I could use bean sprouts but I have to
drain the water after awhile.  Is their a seed / plant that I can
leave in water and watch it grow in water alone?  And if so where can
I find these seeds.

aloha
Rick