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 containers (due to the cost involved in the project) and had never seen so many plants die before. He then showed us a plant he has had in a closed jar in his office for four year (see last picture).
I thought this was a great inquiry project and one I could easily make a year long. We start with inquiry (where we would set up the project) and then move on to weather. In our weather unit we can use the experiment to illustrate the water cycle and transpiration. We then move on to our light unit and we can talk about how light behaves when it hits transparent and translucent objects like our container (in fact you could try different containers and see if that makes a difference). In our astronomy unit we can talk about how sunlight effects growth and in our organisms unit we can use the project to highlight what is needed in a habitat. At the end of the year students can take their plants home.
I know this project could get pricey but i thought it would also make a good grant project.