I took a life science class for educators this summer in upstate South Carolina and one of the inquiry activities we did was with a plant in a jar.
The question we were asked was how long could a plant live in a closed container. We had to come up with a hypothesis and then support our claim. Some people could not make a hypothesis without more information and we wrote those questions on our flip chart paper, i.e. How fast does a plant use up oxygen?
We then planted small plants inside a plastic container (think Glad Ware) and marked the date on the outside. We were told to keep them out of direct sunlight and not to open them until we came back for our follow up class (a month later).
Sadly most of our plants died. My plant died because the leaves started touching the sides and became water logged. Others died because they spent the month in direct sunlight or got rolled around in the back of their car :) The professor said it was the first time he used the glad ware contain...