Re: Variables for my tropism project

Rest of question:

I'm doing a project for PJAS (Pennsylvania Junior Academy of Science) and 
I have a question.  I am about to start a project on phototropism in which 
a bean plant grows through a maze toward a light.  Do you have any 
suggestions for variables yo use?  What design should the maze be?  I have 
participated in PJAS before and it is a great experience.  

Reply:

The phototropism maze experiment can be interesting but is sometimes hard to 
get to work, such as if the maze is too long. It also has disadvantages that 
there is not usually a control treatment, it is hard to replicate, and has no 
easy way to make measurements. One way to add a control might be to make two 
mazes with the same design, one of clear plastic and one of opaque cardboard.

Another interesting phototropism project is to use black plastic 35 mm film 
cans with 3 windows of different colored plastic (red, green, blue). Windows 
are punched in the film can using a paper punch. The film can is placed top 
down and a small seed, such as Wisconsin fast plant, is germinated on moist 
paper towels in the film can lid. The angle of the seedling is measured and 
which window it bends toward is noted. A control is a windowless film can.

Reference


Wisconsin Fast Plant Phototropism Experiments