One possibility is to put a little air in a long balloon, then to stick a
piece of tape on one side. Blowing it up further gives distinct bending.
Another use for this involves the demonstration of stomate opening. Air
blown into two such balloons side-by-side, with their taped sides
adjacent, gives clear evidence for the mechanism of opening of stomates as
"water enters the guard cells."
Al Ruesink
On 12 Oct 1998, Kathleen Archer wrote:
> Dear Colleagues,
> Does anyone have a good physical demonstration of how unequal growth in a
> stem can result in growth towards or away from something? I have 2-D
> pictures, but I was trying to come up with some analogy, or demo, that
> shows clearly how such unequal growth can cause bending in the phototropic
> response, or in twining for vines.
> Thanks for any ideas you have. Again, I'm looking for a physical or visual
> demo, not a static, 2-D picture.
> Kath Archer
>
